Multicenter phase II clinical trial of nilotinib for patients with imatinib-resistant or -intolerant chronic myeloid leukemia from the East Japan CML study group evaluation of molecular response and the efficacy and safety of nilotinib

Naoto Takahashi
Masatomo Miura
Jun Kuroki
Kinuko Mitani
Atsushi Kitabayashi
Osamu Sasaki
Hideo Kimura
Kiyotoshi Imai
Norifumi Tsukamoto
Hideyoshi Noji
Takeshi Kondo
Mutsuhito Motegi
Yuichi Kato
Masayuki Mita
Hajime Saito
Chikashi Yoshida
Yoshihiro Torimoto
Tomofumi Kimura
Yuji Wano
Jun Nomura
Satoshi Yamamoto
Ko Mayama
Riko Honma
Tomohiro Sugawara
Shinji Sato
Atsushi Shinagawa
Maiko Abumiya
Takenori Niioka
Hideo Harigae
Kenichi Sawada
Multicenter phase II clinical trial of nilotinib for patients with imatinib-resistant or -intolerant chronic myeloid leukemia from the East Japan CML study group evaluation of molecular response and the efficacy and safety of nilotinib
R E S E A R C H Open Access
Background: Nilotinib is a second-generation tyrosine kinase inhibitor that exhibits significant efficacy as first-or second-line treatment in patients with chronic myeloid leukemia (CML). We conducted a multicenter Phase II Clinical Trial to evaluate the safety and efficacy of nilotinib among Japanese patients with imatinib-resistant or -intolerant CML-chronic phase (CP) or accelerated phase (AP).Results:We analyzed 49 patients (33 imatinib-resistant and 16 imatinib-intolerant) treated with nilotinib 400 mg twice daily. The major molecular response (MMR) rate was 47.8% at 12 months among 35 patients who did not demonstrate an MMR at study entry. Somatic BCR-ABL1 mutations (Y253H, I418V, and exon 8/9 35-bp insertion [35INS]) were detected in 3 patients at 12 months or upon discontinuation of nilotinib. Although 75.5% of patients were still being treated at 12 months, nilotinib treatment was discontinued because of progressing disease in 1 patient, insufficient effect in 2, and adverse events in 9. There was no statistically significant correlation between MMR and trough concentrations of nilotinib. Similarly, no correlation was observed between trough concentrations and adverse events, except for pruritus and hypokalemia. Hyperbilirubinemia was frequently observed (all grades, 51.0%; grades 2-4, 29%; grades 3-4, 4.1%). Hyperbilirubinemia higher than grade 2 was significantly associated with the uridine diphosphate glucuronosyltransferase (UGT)1A9 I399C/C genotype (P = 0.0086; Odds Ratio, 21.2; 95% Confidence Interval 2.2-208.0).Conclusions: Nilotinib was efficacious and well tolerated by patients with imatinib-resistant or -intolerant CML-CP/AP. Hyperbilirubinemia may be predicted before nilotinib treatment, and may be controlled by reducing the daily dose of nilotinib in patients with UGT1A9 polymorphisms.Trial registration: clinicaltrials.gov: UMIN000002201

Background

Imatinib is used as a first-line therapy for newly diagnosed Philadelphia chromosome-positive chronic myeloid leukemia (Ph + CML) [1,2]; however, some patients fail to respond or become intolerant to this treatment [3]. Nilotinib is a second-generation tyrosine kinase inhibitor (2G-TKI) with higher selectivity and more potent inhibitory effects on the breakpoint cluster region-Abelson 1 (BCR-ABL1) tyrosine kinase than imatinib [4,5]. Several studies have shown hematologic and cytogenetic responses to nilotinib in patients with imatinib-resistant or -intolerant CML [6][7][8][9][10][11]. Although point mutations in BCR-ABL1 are a major cause of imatinib-resistance, nilotinib is effective in patients with known point mutations in this oncogene, with the exception of the T315I mutation [3]. However, the frequency or profile of BCR-ABL1 point mutations has not been determined in daily practice when treating Japanese patients with imatinib-resistant CML in chronic phase (CP) or accelerated phase (AP).

Hyperbilirubinemia is one of the adverse events (AEs) caused by nilotinib. Recently, Giles et al. reported a correlation between hyperbilirubinemia and nilotinib trough concentrations in patients treated with nilotinib [12]. Moreover, nilotinib is not a substrate for uridine diphosphate glucuronosyltransferase 1A1 (UGT1A1) enzymes, but an inhibitor of human UGT1A1 in vitro [13], and CML patients with the UGT1A1*28 polymorphism show an increased risk of nilotinib-induced hyperbilirubinemia [14]. In Japanese cancer patients, UGT1A1*28, UGT1A9*1b, UGT1A1*6 (211G > A), and UGT1A1*60 (3279 T > G) are closely associated with the UGT1A9 IVS1 + 399 (I399C > T) polymorphism, and linkage of I399C > T with these variants has been shown to affect irinotecan metabolism [15]. However, we are not aware of any studies that have examined a correlation between hyperbilirubinemia and the UGT1A9 I399C > T polymorphism.

The goals of the present study were as follows: 1) to determine the major molecular response rate (MMR) at 12 months of twice daily (BID) treatment with 400 mg nilotinib in patients with imatinib-resistant/intolerant CML-CP or -AP; 2) to evaluate molecular responses associated with BCR-ABL1 mutation status or plasma concentrations of nilotinib; and 3) to evaluate the safety of administering 400 mg nilotinib BID, including hyperbilirubinemia development, based on plasma concentrations of nilotinib or polymorphisms of UGT1A1 and UGT1A9.

Results

Patients and treatment

Between March 13, 2009 and January 12, 2011, 51 Japanese patients were recruited, and 49 patients (CML-CP, n = 45; CML-AP, n = 4) were included in the study. Two patients were excluded because they withdrew informed consent.

The cut-off date for overall survival (OS) was January 11, 2013 (24 months after the last patient enrolled).

The demographic and baseline disease characteristics of the patients are described in Table 1. The median age was 62 years. The ratio of men to women was 27:22. Thirtythree (67.3%) and 16 (32.7%) patients were imatinibresistant or imatinib-intolerant, respectively. The median duration of CML in patients was 46.0 months. The median duration of prior imatinib treatment was 43.4 months. Patients were treated with interferon (9 patients; 18.4%) with or without hydroxyurea (8 patients; 16.3%) prior to imatinib therapy. Twenty-three patients (46.9%) showed a complete cytogenetic response (CCyR), and 14 patients (28.6%) showed MMR at the time of entry into the study. Five patients (15.2%) had an additional chromosomal abnormality, and 6 patients (12.2%) had BCR-ABL1 kinase domain mutations at baseline.

Molecular response

Of the 49 patients on trial, 35 did not demonstrate an MMR at study entry and were evaluable for response, using the international scale of standardized quantitative real-time polymerase chain reaction (IS-PCR). The rates of MMR in the evaluable patients were 38.5% and 47.8% at 6 and 12 months, respectively, and the rates of MR4.5 were 7.7% and 13.0% at 6 and 12 months, respectively ( Figure 1). The rates of BCR-ABL1 transcript levels (BCR-ABL IS ) of <1% and <10% at 12 months were 74% and 87%, respectively. The cumulative MMR rates at 12 months were 62.5%, 33.3%, and 24.8% in patients with baselines >0.1-1%, >1-10%, and >10%, respectively. These data represented a significant difference between patients with baseline >0.1-1% and those with baseline >10% (log-rank test, P = 0.0372). The median BCR-ABL1 transcript levels (BCR-ABL IS ) reduced significantly from 10.71% to 0.14% by 12 months in a time dependent manner ( Figure 2).

BCR-ABL1 mutations and nilotinib trough concentrations

Using the direct sequencing identification method (DS), 5 BCR-ABL1 mutations (M244V, F317L, N358D, F359V, and E459K) were detected in 6 patients (12.2%) at baseline. However, M244V, N358D, and E459K were undetectable after nilotinib treatment at 12 months. In contrast, new somatic BCR-ABL1 mutations (Y253H, I418V, and exon 8/9 35-bp insertion [35INS]) were detected in 3 patients (6.1%) at 12 months. These 3 patients did not achieve MMR. The somatic BCR-ABL1 mutation (T315I) was not detected.

Nilotinib trough plasma concentrations were measured by high-performance liquid chromatography (HPLC) methods using blood collected at 3 months. Among 20 patients who continued treatment with nilotinib for 12 months and did not show somatic BCR-ABL1 mutations, trough concentrations (median, 25% to 75%) were increased in 3

Patient status

The disposition of patients at 12 months is summarized in Table 2. Thirty-seven patients (75.5%) were still being treated with nilotinib treatment, while treatment was discontinued for 12 patients (24.5%). AEs were the most frequent reasons for terminating treatment (9 patients; 18.4%). CML-CP progressed in 1 patient with an F317L mutation at baseline. The median actual dose intensity (total nilotinib dose/treatment time) was 651 mg/day. The estimated 36-month OS was 95% in the 37 patients on treatment and 60% in the 12 patients for which treatment was terminated. These data represented a significant difference between the two groups ( Figure 3; log-rank test, P = 0.00844).

Safety

Nilotinib therapy was well tolerated. Although severe nonhematologic AEs were infrequent, 1 patient presenting with grade 3/4 headache and 1 with ischemic heart disease discontinued nilotinib therapy. Grade 3/4 hematologic AEs included anemia (14.3%), neutropenia (28.6%), and thrombocytopenia (18.4%). Although hematologic AEs were managed with dose interruptions or reductions, 5 patients discontinued nilotinib because of repeated or prolonged grade 3/4 thrombocytopenia. Although corrected QT interval (QTc) prolongation at all grades was found in only three patients (6.1%), grade 3/4 QTc prolongation was not detected. QTc prolongation was also easily managed with dose interruptions or reductions, and no patients discontinued treatment because of this AE. Moreover, no episodes of torsades de pointes or death due to arrhythmias were noted. However, 1 patient discontinued nilotinib therapy because of ischemic heart disease without QTc prolongation. Grade 3/4 elevations of total bilirubin occurred in 2 patients (4.1%), and their nilotinib therapy was discontinued because of repeated hyperbilirubinemia despite dose interruptions or reductions. Although other biochemical abnormalities were generally mild, transient, and easily managed with dose interruptions or reductions, hyperbilirubinemia was frequently observed (all grades, 51.0%; grades 2-4, 29%). There was no statistically significant correlation between AEs and trough concentrations of nilotinib except for pruritus (P = 0.0440) and hypokalemia (P = 0.0221).

The UGT1A1 and UGT1A9 polymorphisms were analyzed in all patients to identify a correlation with laboratory abnormalities related to liver function. Although we did not observe a significant correlation between hyperbilirubinemia and UGT1A1 genotype (poor metabolizers with UGT1A1*6/*28, *27/*28, or *28/*28 vs. extensive metabolizers with UGT1A1 *1/*1, *1/*6, *1/*27, or *1/*28),  Figure 3 Overall survival of patients on present or discontinued treatment after 12 months. OS was measured from the date of initial nilotinib administration to the date of death, with a minimum follow-up of 24 months. OS was estimated using the Kaplan-Meier method and compared between groups using the stratified log-rank test. There was a significant difference between the 2 groups (log-rank test, P = 0.00844).

there was a significant correlation with the UGT1A9 I399C/C genotype (P = 0.028) ( Table 3). This genotype was observed in 33% of patients with hyperbilirubinemia higher than grade 2. The UGT1A9 I399C/C genotype was a statistically independent factor according to the results of stepwise forward selection multiple regression analysis (P = 0.0086, Odds Ratio, 21.2; 95% Confidence Interval, 2.2-208.0).

Discussion

The present study revealed that nilotinib therapy was effective in Japanese patients with CML-CP/AP who have developed imatinib resistance or intolerance. Approximately 50% of the patients in this Phase II trial achieved MMR, and the estimated OS at 36 months for patients on treatment was 95%. Responses were more likely in patients with BCR-ABL IS ≤1% at baseline than in those with BCR-ABL IS >1%. In a phase II trial of nilotinib for imatinib resistance or intolerance reported by Kantarjian et al. [9], MMR was achieved in 32% (43 of 134) of patients at 12 months. The lower MMR reported in that study as compared to the rate observed in the present study might be explained by differences in response at baseline. The CCyR at baseline observed by Kantarjian et al. [9] was 3%; in comparison, 26% (9 of 35 patients) showed this response in our trial. In the Expanding Nilotinib Access in Clinical Trials (ENACT), the molecular responses in a subset of French patients (n = 168) every 3 months were evaluated. Thirty-seven percent achieved MMR, and 20% achieved MR4.5 by 12 months [10]. In a phase I/II study of nilotinib treatment of Japanese patients with imatinib-resistant or -intolerant CML or relapsed/refractory Ph + acute lymphoblastic leukemia (ALL), 16 patients with CML-CP were assessed using IS-PCR to detect molecular responses every 3 months [6]. The level of BCR-ABL transcription gradually decreased from baseline, with a 1-log reduction at 6 months and a 2log reduction at 12 months. Our findings are consistent with these observations and suggest that nilotinib is highly active in patients with imatinib-resistant or -intolerant CML-CP/AP. We detected 5 BCR-ABL mutations (M244V, F317L, N358D, F359V, and E459K) in 6 patients at baseline screening. Among these patients, M244V, N358D, and E459K were not detected after nilotinib treatment at 12 months, and 3 patients with these mutations achieved MMR. In contrast, patients with F317L and F359V + E459K mutations showed poor responses to nilotinib treatment, and 1 patient with F317L experienced disease progression. The remaining patient with F359V + E459K mutations did not respond to nilotinib, and treatment was discontinued because of grade 3 thrombocytopenia. A previous study showed that patients with F317L or F359V mutations are resistant to nilotinib [16,17]. The present study also suggests that these mutations at baseline may be associated with less favorable responses to nilotinib.

We detected 3 new mutations in 3 patients after they started nilotinib treatment (Y253H, I418V, and exon 8/9 35-bp insertion). Although the Y253H mutation was less sensitive to nilotinib in an in vitro cell viability assay (IC 50 > 150 nM) [17], the level of BCR-ABL1 transcripts in the Y253H patient in our trial decreased from 8.06% to 0.30%. Qin et al. [18] reported the I418V mutation in a Chinese patient who progressed to blast phase while on imatinib therapy. Although a patient with the somatic I418V mutation in our trial was in second chronic phase at baseline, the disease did not progress. However, the levels of the BCR-ABL1 transcript were maintained from 59.36% at baseline to 50.21% at 12 months. Another rare mutation of BCR-ABL1 is 35INS, which is a 35-bp insertion between ABL kinase domain exons 8 and 9 [19]. This insertion results in a frameshift, leading to the addition of 10 residues and truncation of 653C-terminal residues due to early termination [20]. One patient with 35INS in our trial showed a mild reduction in the level of BCR-ABL1 transcripts from 10.71% at baseline to 2.89%  [21]. Patients who did not achieve MMR and harbored somatic mutations showed relatively poor responses to nilotinib. However, a mutation (e.g. 35INS) might not be causally related, suggesting the possibility of genomic instability, and that other genetic abnormalities might contribute to TKI resistance. Conversely, the T315I mutation, which is known to cause resistance to imatinib and nilotinib, was not detected in the present study.

In the Evaluating Nilotinib Efficacy and Safety in Clinical Trials-newly diagnosed (ENESTnd) patients, the occurrence of all-grade total bilirubin elevation was significantly higher in patients with higher nilotinib exposure [22]. Although we could not identify a correlation between nilotinib trough concentrations and hyperbilirubinemia in the present study, nilotinib trough concentration has been associated with the occurrence of all-grade elevations in total bilirubin [12]. However, to our knowledge this is the first report of a significant correlation between hyperbilirubinemia and the UGT1A9 I399C/C genotype. UGT1A1 catalyzes gluconidation of hepatic bilirubin in humans [23]. The presence of 7-TA nucleotide repeats in the (TA)nTAA promoter region of UGT1A1 (UGT1A1*28) leads to decreased expression of this gene, resulting in high plasma bilirubin levels that form the basis for Gilbert's syndrome [24]. Because nilotinib is a potent noncompetitive inhibitor of human UGT1A1 activity [13], the UGT1A1*28 polymorphism increases the risk of nilotinib induced-hyperbilirubinemia [14,25]. These observations suggest that nilotinib-associated hyperbilirubinemia is very likely the result of inhibition of UGT1A1 activity, combined with genetic defects in UGT1A1. Although, UGT1A9 is also an enzyme of the glucuronidation pathway that transforms small lipophilic molecules, such as steroids, bilirubin, hormones, and drugs, into water-soluble, excretable metabolites, we are not aware of any reports indicating that nilotinib-induced hyperbilirubinemia is related to the UGT1A9 I399C/C genotype. It has been shown that the enzyme function of the UGT1A9 I399C > T genotype does not contribute to variability in UGT1A9 activity [26]. On the other hand, Saito et al. reported the role of UGT1A9 I399C > T in SN-38 glucuronidation in a study of 177 Japanese cancer patients administered irinotecan. Haplotype analysis showed that 98% of UGT1A9 I399C alleles was linked to low-activity genotypes, either UGT1A1*6, *28, or *60 [15]. Our study suggests that hyperbilirubinemia is associated with the UGT1A9 I399C/C genotype. For Japanese patients with CML, hyperbilirubinemia may be predicted before nilotinib treatment and controlled by reducing the daily dose of nilotinib in patients with UGT1A9 polymorphisms.

Conclusions

The results of our study suggest that nilotinib is generally well tolerated by patients and effectively treats imatinibresistant or -intolerant CML-CP/AP.

Methods

Eligibility criteria

Twenty-seven institutions in the East Japan CML study group (EJCML) participated. Patients with Ph + CML-CP/AP who were at least 18 years of age were eligible if they were imatinib-resistant or -intolerant, demonstrated adequate performance status (World Health Organization [WHO] Performance Score [PS] <2), and had normal hepatic, renal, and cardiac functions. Patients were excluded if they exhibited any of the following characteristics: blast phase, QTc >450 ms, and the T315I mutation. Imatinib resistance was defined as an incomplete hematologic response at or after 3 months, no MCyR at 6 months, no CCyR at 12 months, or no MMR at 18 months, according to the criteria of failure and suboptimal response of European LeukemiaNet [3]. Imatinib intolerance was defined as a lack of optimal response because of a grade 3/4 imatinib-related AE, or because of a persistent grade 2 imatinib-related AE, despite optimal supportive care, that persisted for more than 1 month or recurred more than 3 times following reduction of the dose of imatinib.

Clinical trial design and objectives

The study was conducted in accordance with the principles of the Declaration of Helsinki. Informed consent was written by all patients according to institutional guidelines. The study was approved by all institutional review boards and registered with ClinicalTrials.gov (number UMIN000002201). The primary objective of this phase II, single-treatment arm, open-label study was to determine the incidence of MMR at 12 months in patients with imatinib-resistant/intolerant CML-CP/ AP who were treated with nilotinib. The molecular response was evaluated according to IS-PCR upon study entry and every 3 months thereafter. Secondary objectives were to evaluate the relationship between the molecular response and BCR-ABL1 point mutations or plasma concentrations of nilotinib, and between the safety profile of nilotinib and plasma concentrations of the drug and or UGT 1A1/1A9 polymorphisms.

Dosing regimen and concomitant therapy

Nilotinib was administered orally at 400 mg BID, at approximately 12-h intervals. Food was not consumed with the drug, or for at least 2 h before and 1 h after the drug was ingested. The concomitant administration of a strong inhibitor, including grapefruit juice, or inducer of CYP3A, was not allowed in the study.

Molecular response

IS-PCR was performed in a central laboratory (BML Inc., Kawagoe, Japan) using the MolecularMD One-Step qRT-PCR BCR-ABL kit (MolecularMD, Cambridge, MA). An MMR was defined as a 3-log reduction in the level of the BCR-ABL1 transcript using IS-PCR (BCR-ABL IS 0.0032-0.1%). At least 10,000 control genes (ABL1) were required for a sample to be classified as adequate. MR4.5 was defined as ≥4.5-log reduction in the levels of the BCR-ABL1 transcript (BCR-ABL IS ≤0.0032%) in peripheral blood samples, and at least 32,000 control genes were required for a sample to be classified as adequate. Patients with MMR at baseline were considered not eligible and were excluded from the analysis of response rates.

Measurement of nilotinib concentration and Genotyping

Nilotinib trough concentrations (C 0 ) were determined using HPLC as described previously [27]. BCR-ABL1 mutations were analyzed by the DS method as previously described [28]. Genotyping of UGT1A1*6, *27 and *28 was performed using PCR-restriction fragment length polymorphism as described [29,30]. The analysis results obtained from PCR-RFLP were confirmed using a fully automated single nucleotide polymorphism (SNP) detection system (prototype i-densy™, ARKRAY Inc., Kyoto, Japan). The UGT1A9 I399C > T (relative to the end of UGT1A9 exon 1) polymorphism was genotyped by direct sequencing using a PCR procedure as previously described [31]. All genotype frequencies were tested for their consistency with Hardy-Weinberg equilibrium.

Safety analyses

Safety was assessed by determining the frequency and severity of AEs, which included hematologic and biochemical laboratory tests, vital signs, physical examinations (including body weight), WHO PS cardiac function tests (12-lead electrocardiogram, cardiac enzyme test, and echocardiography), and chest X-rays. AEs were graded according to the National Cancer Institute Common Terminology Criteria for AEs (version 3.0).

Statistical analyses

Statistical analyses were performed using SPSS statistical software (version 17.0, SPSS Japan Inc., Tokyo, Japan). Data were presented as number or median values (range or 25% to 75%). Differences in the various parameters between groups were evaluated using the Mann-Whitney U or chi-square tests. Time to MMR was measured from the date of initial nilotinib administration to the date of MMR during the study. OS was measured from the date of initial nilotinib administration to the date of death with a minimum follow-up of 24 months. OS and the cumulative incidence of MMR were estimated using the Kaplan-Meier method and compared between groups using the stratified log-rank test. Stepwise forward selection multiple regression analysis was performed to determine the effect of the variables examined in univariate analysis. A P value of <0.05 was considered significant.

Figure 1
1Molecular responses in patients with imatinib-resistant and imatinib-intolerant CML treated with nilotinib. The molecular response was evaluated according to the international scale of standardized quantitative real-time polymerase chain reaction at the beginning of the study and every 3 months thereafter. The X-axis shows the time-point and patient number for molecular response evaluation. The Y-axis shows the percentage of patients who achieved a molecular response.

Figure 2
2Kinetics of BCR-ABL1 expression. The black bars indicate the median. The gray bars indicate quartiles 1 and 3. The X-axis shows the time-point and patient number for evaluation of molecular responses. The Y-axis shows BCR-ABL1 transcript levels per the international scale of standardized quantitative real-time polymerase chain reaction. patients who achieved MMR at 12 months (774.4 ng/mL, 584.0 to 1364.0) compared to patients without MMR (489.7 ng/mL, 317.6 to 922.5). However, the correlation between MMR at 12 months and trough concentrations of nilotinib was not statistically significant (P = 0.261).

Abbreviations CML: Chronic myeloid leukemia; Ph: Philadelphia chromosome; CP: Chronic phase; AP: Accelerated phase; UGT: Uridine diphosphate glucuronosyltransferase; MMR: Major molecular response; 2G-TKI: Second-generation tyrosine kinase inhibitor; BCR-ABL1: Breakpoint cluster region-Abelson 1; AEs: Adverse events; OS: Overall survival; CCyR: Complete cytogenetic response; MCyR: Major cytogenetic response; IS-PCR: The international scale of standardized quantitative real-time polymerase chain reaction; DS: The direct sequencing identification method; 35INS: Exon8/9 35-bp insertion; QTc: Corrected QT interval; HPLC: High-performance liquid chromatography; WHO: World Health Organization; PS: Performance score. Competing interests NT, KM, TK, YK, CY, SS, HH and KS receive research funding and honoraria for lectures from Novartis Pharmaceuticals, and Bristol-Myers Squibb. The other authors declare that they have no competing interests. Authors' contributions NT and KS designed and performed the research. NT wrote the paper. TN, MA, and MM performed the pharmacokinetic and pharmacogenetic analyses. NT, TN, and MM analyzed the data and prepared the figures. JK, KM, AK, OS, HK, KI, NT, HN, TK, MM, YK, KT, MM, HS, CY, YT, TK, YW, JN, SY, KM, RH, TS, SS, AS, and HH participated in the study design and data analysis. All authors read and approved the final manuscript.

Table 1
1Baseline patient characteristicsParameters
Value

Median age, y (range)
62 (19-84)

Men/women
27/22

Chronic phase/accelerated phase
45/4

Median duration of CML, months (range)
46.0 (3.6-208.2)

Median duration of imatinib therapy, months (range)
43.4 (3.1-101.9)

Imatinib-resistant/-intolerant
33/16

Prior TKI therapy

Imatinib/dasatinib/bosutinib
49/4/2

Other prior therapy

Interferon/hydroxyurea/AraC/BU
9/8/1/1

Cytogenetic response at baseline, Ph +%

>95/>65-95/>35-65/>0-36/0
14/6/4/2/23

BCR-ABL1 level at baseline, IS%

>10/>1-10/>0.1-1/≤0.1
18/7/10/14

Additional chromosomal abnormality, n (%)
5 (15.2)

BCR-ABL1 mutations, n (%)
6 (12.2)

CML, chronic myeloid leukemia; mo, months; TKI, tyrosine kinase inhibitor;
AraC, cytarabine; BU, busulfan; Ph +%, % of Philadelphia chromosome-positive
patients; IS%, international scale %.

Table 2
2Disposition of patients at 12 monthsStatus
N = 49

On treatment
37 (75.5%)

Treatment discontinued
12 (24.5%)

Adverse events
9 (18.4%)

Thrombocytopenia
5 (10.2%)

Hyperbilirubinemia
2 (4.1%)

Heart disease
1 (2.0%)

Headache
1 (2.0%)

No molecular response
2 (4.1%)

Disease progression
1 (2.0%)

Median actual dose intensity, mg/day (range)
651 (198-800)

Table 3
3Liver dysfunction and UGT1A1/1A9 polymorphismsLiver test
Grades 2-4
UGT1A1
UGT1A9 I399C > T

Poor metabolizers
Extensive metabolizers
P-value
C/T + T/T
C/C
P-value

ALT
No
3
41
0.359
39
4
0.111

Yes
1
4
3
2

AST
No
3
44
0.158
41
5
0.237

Yes
1
1
1
1

T.Bil
No
1
35
0.052
34
2
0.028

Yes
3
10
8
4

Nilotinib C 0
Median
687.6
1042.0
0.577
977.5
644.0
0.685

Range (25-75)
(336.1-1906.6)
(614.9-1472.8)
(544.0-1473.0)
(623.0-2292.0)

Poor metabolizers, UGT1A1 *6/*28, *27/*28, or *28/*28; Extensive metabolizers, UGT1A1 *1/*1, *1/*6, *1/*27, or *1/*28; C 0 , trough concentration.

http://www.biomarkerres.org/content/2/1/6
AcknowledgmentsThe authors thank the East Japan CML study group (EJCML), Ibaraki Hematology, Oncology and Palliation Expert Meeting (IB-HOPE), and the Akita CML study group for their participation in this study. This work was supported by a grant (No. 23590168) from the Japan Society for the Promotion of Science, Tokyo, Japan.10Department of Cardiology and Hematology, Fukushima Medical University, Fukushima, Japan.11Stem Cell Transplantation Center, Hokkaido University Hospital, Sapporo, Japan.12Submit your next manuscript to BioMed Central and take full advantage of:
Imatinib compared with interferon and low-dose cytarabine for newly diagnosed chronic-phase chronic myeloid leukemia. S G O'brien, F Guilhot, R A Larson, I Gathmann, M Baccarani, F Cervantes, J J Cornelissen, T Fischer, A Hochhaus, T Hughes, K Lechner, J L Nielsen, P Rousselot, J Reiffers, G Saglio, J Shepherd, B Simonsson, A Gratwohl, J M Goldman, H Kantarjian, K Taylor, G Verhoef, A E Bolton, R Capdeville, B J Druker, Investigators, N Engl J Med. 348O'Brien SG, Guilhot F, Larson RA, Gathmann I, Baccarani M, Cervantes F, Cornelissen JJ, Fischer T, Hochhaus A, Hughes T, Lechner K, Nielsen JL, Rousselot P, Reiffers J, Saglio G, Shepherd J, Simonsson B, Gratwohl A, Goldman JM, Kantarjian H, Taylor K, Verhoef G, Bolton AE, Capdeville R, Druker BJ, IRIS Investigators: Imatinib compared with interferon and low-dose cytarabine for newly diagnosed chronic-phase chronic myeloid leukemia. N Engl J Med 2003, 348:994-1004.

International Randomized Study of Interferon Versus STI571 (IRIS) 7-Year Follow-up: Sustained Survival, Low Rate of Transformation and Increased Rate of Major Molecular Response (MMR) in Patients (pts) with Newly Diagnosed Chronic Myeloid Leukemia in Chronic Phase (CMLCP) Treated with Imatinib. S G O'brien, F Guilhot, J M Goldman, A Hochhaus, T P Hughes, J P Radich, M Rudoltz, J Filian, I Gathmann, B J Druker, R A Larson, 112186IM) [abstract]. BloodO'Brien SG, Guilhot F, Goldman JM, Hochhaus A, Hughes TP, Radich JP, Rudoltz M, Filian J, Gathmann I, Druker BJ, Larson RA: International Randomized Study of Interferon Versus STI571 (IRIS) 7-Year Follow-up: Sustained Survival, Low Rate of Transformation and Increased Rate of Major Molecular Response (MMR) in Patients (pts) with Newly Diagnosed Chronic Myeloid Leukemia in Chronic Phase (CMLCP) Treated with Ima- tinib (IM) [abstract]. Blood 2008, 112:186.

Chronic myeloid leukemia: an update of concepts and management recommendations of European LeukemiaNet. M Baccarani, J Cortes, F Pane, D Niederwieser, G Saglio, J Apperley, F Cervantes, M Deininger, A Gratwohl, F Guilhot, A Hochhaus, M Horowitz, T Hughes, H Kantarjian, R Larson, J Radich, B Simonsson, R T Silver, J Goldman, R Hehlmann, European Leukemianet, J Clin Oncol. 27Baccarani M, Cortes J, Pane F, Niederwieser D, Saglio G, Apperley J, Cervantes F, Deininger M, Gratwohl A, Guilhot F, Hochhaus A, Horowitz M, Hughes T, Kantarjian H, Larson R, Radich J, Simonsson B, Silver RT, Goldman J, Hehlmann R, European LeukemiaNet: Chronic myeloid leukemia: an update of concepts and management recommendations of European LeukemiaNet. J Clin Oncol 2009, 27:6041-6051.

Nilotinib versus imatinib for the treatment of patients with newly diagnosed chronic phase, Philadelphia chromosome-positive, chronic myeloid leukaemia: 24-month minimum follow-up of the phase 3 randomised ENESTnd trial. H M Kantarjian, A Hochhaus, G Saglio, De Souza, C Flinn, I W Stenke, L Goh, Y T Rosti, G Nakamae, H Gallagher, N J Hoenekopp, A Blakesley, R E Larson, R A Hughes, T P , Lancet Oncol. 12Kantarjian HM, Hochhaus A, Saglio G, De Souza C, Flinn IW, Stenke L, Goh YT, Rosti G, Nakamae H, Gallagher NJ, Hoenekopp A, Blakesley RE, Larson RA, Hughes TP: Nilotinib versus imatinib for the treatment of patients with newly diagnosed chronic phase, Philadelphia chromosome-positive, chronic myeloid leukaemia: 24-month minimum follow-up of the phase 3 randomised ENESTnd trial. Lancet Oncol 2011, 12:841-851.

Enestnd 4-year update: continued superiority of Nilotinib vs Imatinib in patients with newly diagnosed Philadelphia chromosome-positive chronic myeloid leukemia in chronic phase. H M Kantarjian, D W Kim, S Issaragrisil, R E Clark, J Reiffers, F E Nicolini, R Pasquini, M Kalaycio, T P Hughes, A Hochhaus, C Kemp, X Fan, R J Waltzman, G Saglio, R A Larson, 1201676Kantarjian HM, Kim DW, Issaragrisil S, Clark RE, Reiffers J, Nicolini FE, Pasquini R, Kalaycio M, Hughes TP, Hochhaus A, Kemp C, Fan X, Waltzman RJ, Saglio G, Larson RA: Enestnd 4-year update: continued superiority of Nilotinib vs Imatinib in patients with newly diagnosed Philadelphia chromosome-positive chronic myeloid leukemia in chronic phase [abstract]. Blood 2012, 120:1676.

Efficacy and safety of nilotinib in Japanese patients with imatinib-resistant or -intolerant Ph + CML or relapsed/refractory Ph + ALL: a 36-month analysis of a phase I and II study. K Usuki, A Tojo, Y Maeda, Y Kobayashi, A Matsuda, K Ohyashiki, C Nakaseko, T Kawaguchi, H Tanaka, K Miyamura, Y Miyazaki, S Okamoto, K Oritani, M Okada, N Usui, T Nagai, T Amagasaki, A Wanajo, T Naoe, Int J Hematol. 95Usuki K, Tojo A, Maeda Y, Kobayashi Y, Matsuda A, Ohyashiki K, Nakaseko C, Kawaguchi T, Tanaka H, Miyamura K, Miyazaki Y, Okamoto S, Oritani K, Okada M, Usui N, Nagai T, Amagasaki T, Wanajo A, Naoe T: Efficacy and safety of nilotinib in Japanese patients with imatinib-resistant or -intolerant Ph + CML or relapsed/refractory Ph + ALL: a 36-month analysis of a phase I and II study. Int J Hematol 2012, 95:409-419.

A Phase I/II study of nilotinib in Japanese patients with imatinib-resistant or -intolerant Ph + CML or relapsed/refractory Ph + ALL. A Tojo, K Usuki, A Urabe, Y Maeda, Y Kobayashi, I Jinnai, K Ohyashiki, M Nishimura, T Kawaguchi, H Tanaka, K Miyamura, Y Miyazaki, T Hughes, S Branford, S Okamoto, J Ishikawa, M Okada, N Usui, H Tanii, T Amagasaki, H Natori, T Naoe, Int J Hematol. 89Tojo A, Usuki K, Urabe A, Maeda Y, Kobayashi Y, Jinnai I, Ohyashiki K, Nishimura M, Kawaguchi T, Tanaka H, Miyamura K, Miyazaki Y, Hughes T, Branford S, Okamoto S, Ishikawa J, Okada M, Usui N, Tanii H, Amagasaki T, Natori H, Naoe T: A Phase I/II study of nilotinib in Japanese patients with imatinib-resistant or -intolerant Ph + CML or relapsed/refractory Ph + ALL. Int J Hematol 2009, 89:679-688.

Nilotinib in imatinib-resistant or imatinib-intolerant patients with chronic myeloid leukemia in chronic phase: 48-month follow-up results of a phase II study. F J Giles, Le Coutre, P D Pinilla-Ibarz, J Larson, R A Gattermann, N Ottmann, O G Hochhaus, A Radich, J P Saglio, G Hughes, T P Martinelli, G Kim, D W Novick, S Gillis, K Fan, X Cortes, J Baccarani, M Kantarjian, H M , Leukemia. 27Giles FJ, Le Coutre PD, Pinilla-Ibarz J, Larson RA, Gattermann N, Ottmann OG, Hochhaus A, Radich JP, Saglio G, Hughes TP, Martinelli G, Kim DW, Novick S, Gillis K, Fan X, Cortes J, Baccarani M, Kantarjian HM: Nilotinib in imatinib-resistant or imatinib-intolerant patients with chronic myeloid leukemia in chronic phase: 48-month follow-up results of a phase II study. Leukemia 2013, 27:107-112.

PD: Nilotinib is effective in patients with chronic myeloid leukemia in chronic phase after imatinib resistance or intolerance: 24-month follow-up results. H M Kantarjian, F J Giles, K N Bhalla, J Pinilla-Ibarz, R A Larson, N Gattermann, O G Ottmann, A Hochhaus, J P Radich, G Saglio, T P Hughes, G Martinelli, D W Kim, Y Shou, N J Gallagher, R Blakesley, M Baccarani, J Cortes, Le Coutre, Blood. 117Kantarjian HM, Giles FJ, Bhalla KN, Pinilla-Ibarz J, Larson RA, Gattermann N, Ottmann OG, Hochhaus A, Radich JP, Saglio G, Hughes TP, Martinelli G, Kim DW, Shou Y, Gallagher NJ, Blakesley R, Baccarani M, Cortes J, Le Coutre PD: Nilotinib is effective in patients with chronic myeloid leukemia in chronic phase after imatinib resistance or intolerance: 24-month follow-up results. Blood 2011, 117:1141-1145.

Expanding Nilotinib Access in Clinical Trials (ENACT): an open-label, multicenter study of oral nilotinib in adult patients with imatinib-resistant or imatinib-intolerant Philadelphia chromosome-positive chronic myeloid leukemia in the chronic phase. F E Nicolini, A Turkina, Z X Shen, N Gallagher, S Jootar, B L Powell, De Souza, C Zheng, M Szczudlo, T , Le Coutre, P , Cancer. 118Nicolini FE, Turkina A, Shen ZX, Gallagher N, Jootar S, Powell BL, De Souza C, Zheng M, Szczudlo T, Le Coutre P: Expanding Nilotinib Access in Clinical Trials (ENACT): an open-label, multicenter study of oral nilotinib in adult patients with imatinib-resistant or imatinib-intolerant Philadelphia chromosome-positive chronic myeloid leukemia in the chronic phase. Cancer 2012, 118:118-126.

Initial molecular response at 3 months may predict both response and event-free survival at 24 months in imatinib-resistant or -intolerant patients with Philadelphia chromosome-positive chronic myeloid leukemia in chronic phase treated with nilotinib. S Branford, D W Kim, S Soverini, A Haque, Y Shou, R C Woodman, H M Kantarjian, G Martinelli, J P Radich, G Saglio, A Hochhaus, T P Hughes, M C Müller, J Clin Oncol. 30Branford S, Kim DW, Soverini S, Haque A, Shou Y, Woodman RC, Kantarjian HM, Martinelli G, Radich JP, Saglio G, Hochhaus A, Hughes TP, Müller MC: Initial molecular response at 3 months may predict both response and event-free survival at 24 months in imatinib-resistant or -intolerant patients with Philadelphia chromosome-positive chronic myeloid leukemia in chronic phase treated with nilotinib. J Clin Oncol 2012, 30:4323-4329.

Nilotinib population pharmacokinetics and exposure-response analysis in patients with imatinib-resistant or -intolerant chronic myeloid leukemia. F J Giles, O Q Yin, W M Sallas, Le Coutre, P D Woodman, R C Ottmann, O G Baccarani, M Kantarjian, H M , Eur J Clin Pharmacol. 69Giles FJ, Yin OQ, Sallas WM, Le Coutre PD, Woodman RC, Ottmann OG, Baccarani M, Kantarjian HM: Nilotinib population pharmacokinetics and exposure-response analysis in patients with imatinib-resistant or -intolerant chronic myeloid leukemia. Eur J Clin Pharmacol 2013, 69:813-823.

The small-molecule tyrosine kinase inhibitor nilotinib is a potent noncompetitive inhibitor of the SN-38 glucuronidation by human UGT1A1. K Fujita, M Sugiyama, Y Akiyama, Y Ando, Y Sasaki, Cancer Chemother Pharmacol. 67Fujita K, Sugiyama M, Akiyama Y, Ando Y, Sasaki Y: The small-molecule tyrosine kinase inhibitor nilotinib is a potent noncompetitive inhibitor of the SN-38 glucuronidation by human UGT1A1. Cancer Chemother Pharmacol 2011, 67:237-241.

UGT1A1 promoter polymorphism increases risk of nilotinib-induced hyperbilirubinemia. J B Singer, Y Shou, F Giles, H M Kantarjian, Y Hsu, A S Robeva, P Rae, A Weitzman, J M Meyer, M Dugan, O G Ottmann, Leukemia. 21Singer JB, Shou Y, Giles F, Kantarjian HM, Hsu Y, Robeva AS, Rae P, Weitzman A, Meyer JM, Dugan M, Ottmann OG: UGT1A1 promoter polymorphism increases risk of nilotinib-induced hyperbilirubinemia. Leukemia 2007, 21:2311-2315.

Close association of UGT1A9 IVS1 + 399C > T with UGT1A1*28, *6, or *60 haplotype and its apparent influence on 7-ethyl-10-hydroxycamptothecin (SN-38) glucuronidation in Japanese. Y Saito, K Sai, K Maekawa, N Kaniwa, K Shirao, T Hamaguchi, N Yamamoto, H Kunitoh, Y Ohe, Y Yamada, T Tamura, T Yoshida, H Minami, A Ohtsu, Y Matsumura, N Saijo, J Sawada, Drug Metab Dispos. 37Saito Y, Sai K, Maekawa K, Kaniwa N, Shirao K, Hamaguchi T, Yamamoto N, Kunitoh H, Ohe Y, Yamada Y, Tamura T, Yoshida T, Minami H, Ohtsu A, Matsumura Y, Saijo N, Sawada J: Close association of UGT1A9 IVS1 + 399C > T with UGT1A1*28, *6, or *60 haplotype and its apparent influence on 7-ethyl-10-hydroxycamptothecin (SN-38) glucuronidation in Japanese. Drug Metab Dispos 2009, 37:272-276.

Activity of bosutinib, dasatinib, and nilotinib against 18 imatinib-resistant BCR/ABL mutants. S Redaelli, R Piazza, R Rostagno, V Magistroni, P Perini, M Marega, C Gambacorti-Passerini, F Boschelli, J Clin Oncol. 27Redaelli S, Piazza R, Rostagno R, Magistroni V, Perini P, Marega M, Gambacorti-Passerini C, Boschelli F: Activity of bosutinib, dasatinib, and nilotinib against 18 imatinib-resistant BCR/ABL mutants. J Clin Oncol 2009, 27:469-471.

Impact of baseline BCR-ABL mutations on response to nilotinib in patients with chronic myeloid leukemia in chronic phase. T Hughes, G Saglio, S Branford, S Soverini, D W Kim, M C Muller, G Martinelli, J Cortes, L Beppu, E Gottardi, D Kim, P Erben, Y Shou, A Haque, N Gallagher, J Radich, A Hochhaus, J Clin Oncol. 27Hughes T, Saglio G, Branford S, Soverini S, Kim DW, Muller MC, Martinelli G, Cortes J, Beppu L, Gottardi E, Kim D, Erben P, Shou Y, Haque A, Gallagher N, Radich J, Hochhaus A: Impact of baseline BCR-ABL mutations on response to nilotinib in patients with chronic myeloid leukemia in chronic phase. J Clin Oncol 2009, 27:4204-4210.

Characteristics of BCR-ABL kinase domain point mutations in Chinese imatinib-resistant chronic myeloid leukemia patients. Y Qin, S Chen, B Jiang, Q Jiang, H Jiang, J Li, L Li, Y Lai, Y Liu, X Huang, Ann Hematol. 90Qin Y, Chen S, Jiang B, Jiang Q, Jiang H, Li J, Li L, Lai Y, Liu Y, Huang X: Characteristics of BCR-ABL kinase domain point mutations in Chinese imatinib-resistant chronic myeloid leukemia patients. Ann Hematol 2011, 90:47-52.

Press RD: An intron-derived insertion/truncation mutation in the BCR-ABL kinase domain in chronic myeloid leukemia patients undergoing kinase inhibitor therapy. J Laudadio, M W Deininger, M J Mauro, B J Druker, J Mol Diagn. 10Laudadio J, Deininger MW, Mauro MJ, Druker BJ, Press RD: An intron-derived insertion/truncation mutation in the BCR-ABL kinase domain in chronic myeloid leukemia patients undergoing kinase inhibitor therapy. J Mol Diagn 2008, 10:177-180.

BCR-ABL alternative splicing as a common mechanism for imatinib resistance: evidence from molecular dynamics simulations. T S Lee, W Ma, X Zhang, F Giles, J Cortes, H Kantarjian, M Albitar, Mol Cancer Ther. 7Lee TS, Ma W, Zhang X, Giles F, Cortes J, Kantarjian H, Albitar M: BCR-ABL alternative splicing as a common mechanism for imatinib resistance: evidence from molecular dynamics simulations. Mol Cancer Ther 2008, 7:3834-3841.

The BCR-ABL35INS insertion/truncation mutant is kinase-inactive and does not contribute to tyrosine kinase inhibitor resistance in chronic myeloid leukemia. T O'hare, M S Zabriskie, C A Eide, A Agarwal, L T Adrian, H You, A S Corbin, F Yang, R D Press, V M Rivera, J Toplin, S Wong, M W Deininger, B J Druker, Blood. 118O'Hare T, Zabriskie MS, Eide CA, Agarwal A, Adrian LT, You H, Corbin AS, Yang F, Press RD, Rivera VM, Toplin J, Wong S, Deininger MW, Druker BJ: The BCR-ABL35INS insertion/truncation mutant is kinase-inactive and does not contribute to tyrosine kinase inhibitor resistance in chronic myeloid leukemia. Blood 2011, 118:5250-5254.

Population pharmacokinetic and exposure-response analysis of nilotinib in patients with newly diagnosed Ph + chronic myeloid leukemia in chronic phase. R A Larson, O Q Yin, A Hochhaus, G Saglio, R E Clark, H Nakamae, N J Gallagher, E Demirhan, T P Hughes, H M Kantarjian, Le Coutre, P D , Eur J Clin Pharmacol. 68Larson RA, Yin OQ, Hochhaus A, Saglio G, Clark RE, Nakamae H, Gallagher NJ, Demirhan E, Hughes TP, Kantarjian HM, Le Coutre PD: Population pharmacokinetic and exposure-response analysis of nilotinib in patients with newly diagnosed Ph + chronic myeloid leukemia in chronic phase. Eur J Clin Pharmacol 2012, 68:723-733.

Bilirubin UDP-glucuronosyltransferase 1 is the only relevant bilirubin glucuronidating isoform in man. P J Bosma, J Seppen, B Goldhoorn, C Bakker, Oude Elferink, R P Chowdhury, J R Chowdhury, N R Jansen, P L , J Biol Chem. 269Bosma PJ, Seppen J, Goldhoorn B, Bakker C, Oude Elferink RP, Chowdhury JR, Chowdhury NR, Jansen PL: Bilirubin UDP-glucuronosyltransferase 1 is the only relevant bilirubin glucuronidating isoform in man. J Biol Chem 1994, 269:17960-17964.

and Rotor syndrome). Cp ; Strassburg, Gilbert-Meulengracht, Dubin-Johnson Crigler-Najjar, Hyperbilirubinemia syndromes. 24Strassburg CP: Hyperbilirubinemia syndromes (Gilbert-Meulengracht, Crigler-Najjar, Dubin-Johnson, and Rotor syndrome). Best Pract Res Clin Gastroenterol 2010, 24:555-571.

Association between severe toxicity of nilotinib and UGT1A1 polymorphisms in Japanese patients with chronic myelogenous leukemia. T Shibata, Y Minami, A Mitsuma, S Morita, M Inada-Inoue, T Oguri, T Shimokata, M Sugishita, T Naoe, Y Ando, Int J Clin Oncol. Epub ahead of printShibata T, Minami Y, Mitsuma A, Morita S, Inada-Inoue M, Oguri T, Shimokata T, Sugishita M, Naoe T, Ando Y: Association between severe toxicity of nilotinib and UGT1A1 polymorphisms in Japanese patients with chronic myelogenous leukemia. Int J Clin Oncol 2013 [Epub ahead of print].

Lack of association between common polymorphisms in UGT1A9 and gene expression and activity. J Ramirez, W Liu, S Mirkov, A A Desai, P Chen, S Das, F Innocenti, M J Ratain, Drug Metab Dispos. 35Ramirez J, Liu W, Mirkov S, Desai AA, Chen P, Das S, Innocenti F, Ratain MJ: Lack of association between common polymorphisms in UGT1A9 and gene expression and activity. Drug Metab Dispos 2007, 35:2149-2153.

High-performance liquid chromatography with solid-phase extraction for the quantitative determination of nilotinib in human plasma. M Miura, N Takahashi, K Sawada, Biomed Chromatogr. 24Miura M, Takahashi N, Sawada K: High-performance liquid chromatography with solid-phase extraction for the quantitative determination of nilotinib in human plasma. Biomed Chromatogr 2010, 24:789-793.

High frequency of point mutations clustered within the adenosine triphosphate-binding region of BCR/ABL in patients with chronic myeloid leukemia or Ph-positive acute lymphoblastic leukemia who develop imatinib (STI571) resistance. S Branford, Z Rudzki, S Walsh, A Grigg, C Arthur, K Taylor, R Herrmann, K P Lynch, T P Hughes, Blood. 99Branford S, Rudzki Z, Walsh S, Grigg A, Arthur C, Taylor K, Herrmann R, Lynch KP, Hughes TP: High frequency of point mutations clustered within the adenosine triphosphate-binding region of BCR/ABL in patients with chronic myeloid leukemia or Ph-positive acute lymphoblastic leukemia who develop imatinib (STI571) resistance. Blood 2002, 99:3472-3475.

Polymorphisms of UDP-glucuronosyltransferase gene and irinotecan toxicity: a pharmacogenetic analysis. Y Ando, H Saka, M Ando, T Sawa, K Muro, H Ueoka, A Yokoyama, S Saitoh, K Shimokata, Y Hasegawa, Cancer Res. 60Ando Y, Saka H, Ando M, Sawa T, Muro K, Ueoka H, Yokoyama A, Saitoh S, Shimokata K, Hasegawa Y: Polymorphisms of UDP-glucuronosyltransferase gene and irinotecan toxicity: a pharmacogenetic analysis. Cancer Res 2000, 60:6921-6926.

Influence of drug transporters and UGT polymorphisms on pharmacokinetics of phenolic glucuronide metabolite of mycophenolic acid in Japanese renal transplant recipients. M Miura, H Kagaya, S Satoh, K Inoue, M Saito, T Habuchi, T Suzuki, Ther Drug Monit. 30Miura M, Kagaya H, Satoh S, Inoue K, Saito M, Habuchi T, Suzuki T: Influence of drug transporters and UGT polymorphisms on pharmacokinetics of phenolic glucuronide metabolite of mycophenolic acid in Japanese renal transplant recipients. Ther Drug Monit 2008, 30:559-564.

The novel UGT1A9 intronic I399 polymorphism appears as a predictor of 7-ethyl-10-hydroxycamptothecin glucuronidation levels in the liver. H Girard, L Villeneuve, M H Court, L C Fortier, P Caron, Q Hao, Von Moltke, L L Greenblatt, D J Guillemette, C , 10.1186/2050-7771-2-6Drug Metab Dispos. 34Girard H, Villeneuve L, Court MH, Fortier LC, Caron P, Hao Q, Von Moltke LL, Greenblatt DJ, Guillemette C: The novel UGT1A9 intronic I399 polymorphism appears as a predictor of 7-ethyl-10-hydroxycamptothecin glucuronidation levels in the liver. Drug Metab Dispos 2006, 34:1220-1228. doi:10.1186/2050-7771-2-6

Multicenter phase II clinical trial of nilotinib for patients with imatinib-resistant or -intolerant chronic myeloid leukemia from the East Japan CML study group evaluation of molecular response and the efficacy and safety of nilotinib. Takahashi, Biomarker Research. 26Cite this article asCite this article as: Takahashi et al.: Multicenter phase II clinical trial of nilotinib for patients with imatinib-resistant or -intolerant chronic myeloid leukemia from the East Japan CML study group evaluation of molecular response and the efficacy and safety of nilotinib. Biomarker Research 2014 2:6.


Future physicians and tobacco: an online survey of the habits, beliefs and knowledge base of medical students at a Canadian University

Amanda J Vanderhoek
Fadi Hammal
Alyssa Chappell
T Cameron Wild
Tobias Raupach
Barry A Finegan
Future physicians and tobacco: an online survey of the habits, beliefs and knowledge base of medical students at a Canadian University
R E S E A R C H Open Access
Background:Little is known about the knowledge and attitudes towards tobacco use among medical students in Canada. Our objectives were to estimate the prevalence of tobacco use among medical students, assess their perceived level of education about tobacco addiction management and their preparedness to address tobacco use with their future patients.Methods:A cross-sectional online survey was administered to University of Alberta undergraduate medical school trainees. The 32-question survey addressed student demographics, tobacco use, knowledge and attitudes around tobacco and waterpipe smoking, tobacco education received in medical school, as well as knowledge and competency regarding tobacco cessation interventions. Results: Of 681 polled students, 301 completed the survey. Current (defined as "use within the last 30 days") cigarette, cigar/cigarillo and waterpipe smoking prevalence was 3.3%, 6% and 6%, respectively. One third of the respondents had ever smoked a cigarette, but 41% had tried cigars/cigarillos and 40% had smoked a waterpipe at some time in the past. Students reported moderate levels of education on a variety of tobacco-related subjects but were well-informed on the role of tobacco in disease causation. The majority of students in their final two years of training felt competent to provide tobacco cessation interventions, but only 10% definitively agreed that they had received enough training in this area.Conclusions: Waterpipe exposure/current use was surprisingly high among this sample of medical students, a population well educated about the role of tobacco in disease causation. The majority of respondents appeared to be adequately prepared to manage tobacco addiction but education could be improved, particularly training in behavioral modification techniques used in tobacco use cessation.

Background

Physicians play a crucial role in preventing disease and promoting a healthy lifestyle [1]. The willingness of physicians to engage in providing prevention counseling is influenced by many factors, especially, their training [2], their own personal habits and their self-confidence in doing so effectively [3,4]. This "personal-clinical relationship" has been well validated among Canadian and US physicians [4,5] and is especially relevant in the area of tobacco control, as non-smoking physicians are more likely to report encouraging cessation among their patients than those who smoke [4]. A similar trend is found among medical students, where healthy personal practices are found to equate with engagement in preventive counseling and appreciation of importance of this role as part of their professional responsibility [6]. A combination of didactic and interactive training during medical school can improve knowledge, attitude, and counseling skills regarding tobacco cessation and other forms of behavioral change [7,8]. There is very limited information about the prevalence of smoking among Canadian medical school students and their perceived level of education and preparedness to address tobacco use with their patients [9]. There are no data on waterpipe use in medical students, a popular emerging method of smoking that is frequently thought of as less harmful than cigarettes [10].

In this cross-sectional survey of University of Alberta undergraduate medical students, we sought to report on their smoking status, what their opinions were regarding the risks of waterpipe smoking, the extent of their knowledge about the role of tobacco in disease causation and their understanding of the relative effectiveness of currently used tobacco cessation interventions. Finally, we requested they provide their views on the education they received about tobacco addiction management, their self-perceived capacity/competency to treat patients with tobacco addiction and the role of physician leadership in advancing tobacco control and management.

Methods

Students in the undergraduate Doctor of Medicine program in the Faculty of Medicine and Dentistry at the University of Alberta, Edmonton, Canada, were invited to participate in a cross-sectional, anonymous on-line survey. The questionnaire was available on-line for a sixweek period in 2012. During that time, we tracked the completion of questionnaires, noting the date and time of survey completion. Four email reminders were sent out during the course of the survey, each of which contained a summary of the invitation letter and link to the questionnaire.

The undergraduate program spans four years, beginning with two years of preclinical education. In the third year, students begin their clinical education, which consists of two years of clerkship in a variety of medical specialties. During the fourth year of their education, students are given three months of protected time to undergo 10-15 weeks of electives, interview for residency positions and prepare for graduation. The pre-clinical medical curriculum at the University of Alberta is based on system blocks focusing on small group learning. Tobacco related education is integrated into each system block with no special block devoted solely to tobacco. Therefore it was difficult to estimate how many hours of tobacco education medical students receive throughout their undergraduate medical education. There were approximately 170 students enrolled in each year of the program for the 2011/ 12 school year. All 681 students in the graduating classes of 2012 to 2015 (46.4% female) were eligible to participate in the survey.

Development of the survey instrument

The questions were developed with guidance of previously used questionnaires on tobacco and education among medical students [11,12] and with the support of a consultant experienced in social research methodology who provided assistance in the selection, placement, response sets, content and face validity of the question items. In all questions on knowledge, opinion and attitude, a six-point Likert scale was used where 1 was negative and 6 positive. The survey instrument consisted of 32 questions with an estimated completion time of five to ten minutes. Six domains of questions were asked of respondents:

1. Student demographics and current tobacco use (defined as "use within the last 30 days") and "ever tobacco use" (9 questions) 2. Knowledge and attitudes toward tobacco and waterpipe smoking (5 questions) 3. Health implications of smoking (3 questions) 4. Effectiveness and priority of tobacco cessation interventions (1 question) 5. Perceived education and competency (10 questions) 6. Perceived physicians role in tobacco cessation (4 questions).

Procedures

The Health Ethics Review Board at the University of Alberta approved the survey. The Undergraduate Medical Education (UME) office posted a bulletin about the survey on the on-line learning community for the Faculty of Medicine and Dentistry that included a description of the survey, a link to the invitation letter and a link to the survey instrument. The UME office subsequently sent an email to all medical students alerting them to the bulletin. Students who read the bulletin and clicked on the link to the survey were taken to a secure internet site (FluidSurveys, Ottawa, ON, Canada) where they were asked to complete an anonymous informed consent form if they wished to participate in the survey. Potential participants were informed that for voluntarily completing the questionnaire, they were eligible to receive either a $5.00 unique OneCard certificate (the OneCard is the student identity card that can contain monetary value to purchase certain services and products on the university campus) or a $5.00 Starbucks e-gift card.

Only those who wanted to receive the incentive were asked to provide their email address at the end of the questionnaire. The email addresses were separated from the survey data to maintain anonymity.

Statistical analysis

Incomplete questionnaires were not used in the analysis. Demographic and "current use" and "ever use" data were summarized using descriptive statistics. Categorical variables were reported using frequencies, while continuous data were analyzed using means and standard deviations. All group comparisons for categorical variables were conducted using chi-square analyses where two-sided p-values <0.05 were considered statistically significant. Multivariate analysis was used to identify predictors for competency to counsel patients and prescribe medication. The Statistical Package for the Social Sciences (SPSS, Version 19.0, IBM, Armonk, NY, USA) was used for data management and statistical analyses.

Results

Response rate

We received 301 completed surveys and 12 incomplete responses out of 681 potential respondents. The survey response rate was calculated as: (number of completes) / (number of completes + number of incompletes + number of refusals), which in this case was: (301) / (681) = 44.2%. The highest response rate (65%) was from students who had just completed their first year of school and the lowest (25%) from recent graduates.

Sample characteristics

Of the 301 respondents, 51% were females and the mean age was 24.4 years (SD = 2.8). About 37% of respondents had just completed their first year of medical school, while 14% of respondents had just graduated from their fourth year (Table 1).

Smoking prevalence and opinions

More students had ever smoked cigars/cigarillos (40.5%) or waterpipes (39.9%) than those who had ever smoked a cigarette (29.9%). Similarly, current smoking rates were higher for cigars/cigarillos (6.6%) and waterpipe (6.0%) than for cigarettes (3.3%).

Among those who had ever smoked a waterpipe, the majority (53.8%), had done so at a shisha/hookah café. The most common materials reported to be smoked in a waterpipe were tobacco (59.7%) and herbal products (42.9%). There was no difference in beliefs about the health consequences of waterpipe smoking between those who indicated that they were "ever" smokers and nonsmokers. A significant minority of all respondents believed that smoking tobacco in a waterpipe was less harmful than smoking tobacco in the form of a cigarette. Surprisingly, 10% of those who had smoked a waterpipe indicated that they did not think that smoking tobacco in a waterpipe was addictive, a belief not shared by nonsmokers ( Table 2).

Perception of exposure to tobacco related education

Respondents reported moderate levels of education on a variety of tobacco-related subjects. The overall tobacco education score was 3.25 (95% CI 3.14-3.36). Limited education was reported on the role of tobacco in addiction pathology, pregnancy and pediatrics and on the pharmacotherapy of nicotine addiction. Respondents reported greater exposure to education about counseling and motivational interviewing techniques and the role of tobacco in public health and the most education about the role of tobacco causing in disease. Less than 10% of respondents reported that they received "a lot of education" about any of the subject areas surveyed (Figure 1).

Perceived competence in tobacco cessation interventions

Fewer than 10% of respondents in any year, strongly agreed with the statements "I have received enough training on tobacco cessation interventions"; "I am comfortable providing medications to assist in tobacco cessation" and "I am familiar with the current guidelines for treating tobacco use", however, some 30% of final-year students felt knowledgeable (strongly agree and agree somewhat) about guidelines and were satisfied with the education they have received. Fifty per cent felt competent to counsel patients and prescribe medication. A difference in self-reported competence was apparent in the responses as students progressed through the program ( Figure 2). Multivariate analysis showed that the year of education was the only significant factor in predicting if students were likely to counsel smokers who are seeking help to give up smoking.

Health consequences of smoking

Most students believed that cigarettes are either mostly or totally responsible for chronic obstructive pulmonary disease (95%), lung cancer (91%), coronary artery disease (54%) and, to a lesser extent, bladder cancer ( Figure 3). Most students thought that cigarettes were not at all or not very responsible for the development of gallstones and appendicitis. The majority of students (92%) agreed that non-smokers could expect to live an average of ten years longer than smokers; however, they did not believe that quitting at the age of 30 would extend a smoker's life expectancy to that of a life-long non-smoker.

Tobacco cessation

Most participants believed that pharmacotherapies alone were at least somewhat effective in tobacco cessation ( Figure 4). The intervention most regarded as extremely effective by 17.1% of students was "a group cessation program including several sessions and nicotine replacement therapy". Most participants thought that both advice from a general practitioner and willpower alone were somewhat ineffective. Respondents generally agreed (85%) that physicians play a leadership role in tobacco management and that it is a priority for physicians. However, nearly one-third of students did not think that physicians are motivated to implement tobacco cessation programs with their patients and 35% of respondents did not believe that tobacco cessation counseling is a priority in Alberta.

Discussion

This survey was carried out to assess the use of tobacco products and the tobacco-related attitudes, knowledge, and education of University of Alberta medical students. Self-reported cigarette use among our survey population was low, but lifetime exposure to alternative methods of tobacco consumption (waterpipe, cigars) was surprisingly common. While students reported some exposure to all domains of tobacco education surveyed, they expressed only moderate confidence in their own ability to counsel and treat smokers. This was despite correctly identifying the key role of tobacco in the pathogenesis of lung cancer, chronic obstructive pulmonary disease and coronary artery disease. Self-reported current cigarette use among our study population was low (3.3%). In contrast, recent surveys of medical students in Germany, the USA and the UK

Proportion of students (%)

Year  Figure 1 Perceived amount of tobacco education received in each year of medical school regarding six special areas. Students from each year were asked to rate the amount of tobacco education they received in the past year on a scale of 1 to 6 with "1" being "no education" and "6" being "a lot of education" for each of the six special areas (panels a to f). Student responses were stratified according to their year of medical education from 1-4.

Proportion of students (%)

Year Figure 2 Self-reported competencies of medical students regarding tobacco cessation interventions. Students were asked to rate their level of agreement with the above statements. The rating was on a scale of 1 to 6 with "1" being "strongly disagree" and "6" being "completely agree" for each of the four tobacco cessation interventions (panels a to d). Student responses were stratified according to their year of medical education from 1-4.

Proportion of students (%)

Totally responsible Not at all responsible Figure 3 The responsibility of cigarettes for six diseases. Diseases were given in a randomized order and the students were asked to rate the degrees to which cigarettes are responsible for each disease. The rating was on a scale of 1 to 6 with "1" being "not at all responsible" and "6" being "totally responsible". COPD, chronic obstructive pulmonary disease.

reported much higher rates of cigarette use (20%, 11% and 10%, respectively) [11][12][13]. The only other recent survey of cigarette use among Canadian medical students reported similar data to that reported in this study [9]. The latest WHO estimates for adult cigarette smoking prevalence were 29% in Germany, 24% in the United Kingdom, 26% in the United States, and 17% in Canada [14]. Although self-reported cigarette use among medical students in Canada is lower than the use of cigarettes among the general population, it is concerning that current cigar/cigarillo use among this health aware group is equivalent to that in the general population and exceeds it in the case of the use of the waterpipe [15]. Although 40% of respondents indicated that they had smoked a waterpipe at some point, they were skeptical of the alleged safety of this practice. Several studies confirm their suspicions, asserting that waterpipe smoking is both harmful and addictive; smokers are exposed to high levels of particulate matters, carbon monoxide, and other chemicals, which affect lung health [16]. More than half of those who had ever smoked a waterpipe did so in a public café. The proportion of students being introduced to waterpipe in these venues highlights the importance of smoke-free legislation being applied to waterpipe cafes [17]. Almost half of the students who ever smoked the waterpipe did so at home or in other locations, suggesting that we may be witnessing a normalization of waterpipe smoking in Canada among young adults. Most respondents indicated that they chose to smoke tobacco in their waterpipes, a practice that carries with it the real risk of nicotine addiction [18]. While the causative role of tobacco in the etiology of disease was well known by respondents, they indicated that they received less education about the management of tobacco use in pregnancy and childhood. This may well be a reflection of the relative paucity of research and the difficulty in treating tobacco addiction in both these groups. Tobacco use during pregnancy is a key modifiable risk factor for innumerable perinatal complications but poor implementation and psychosocial barriers frequently compromise the success of cessation efforts [19]. Nevertheless, it is vital that physicians champion smoking cessation interventions as a routine part of prenatal care, as the long term benefits to both child and mother are inestimable. The adverse consequences of second hand smoke on child health have been well described and the imperative for treatment of nicotine addiction compelling [20]. The results of our survey suggest that a focused tobacco management module in both the pediatric and obstetric blocks could well be appropriate with an emphasis on motivational techniques to promote behavior change.

Less than 10% of graduating respondents strongly agreed that they were familiar with the current guidelines for treating tobacco use, in comparison, 99% of general practitioners are familiar with hypertension guidelines and 90% of clinicians are familiar with the guidelines for the treatment of angina [21,22].

These data point to the need to encourage widespread exposure of medical students in Canada to the excellent CAN-ADAPTT resource which includes not only guideline information but also links to a range of educational resources including instruction of motivational interviewing techniques [23].

It was disappointing that although a role for leadership by physicians in tobacco addiction management was acknowledged, one-third of respondents believed that physicians were not motivated to implement tobacco cessation programs and more than half thought that their advice would be ineffective. These data mirrored findings in a

Proportion of students (%)

Extremely effective Not at all effective Figure 4 Perceived effectiveness of smoking cessation methods. Methods were given in a randomized order and the students were asked to rate the effectiveness of each method on a scale of 1 to 6 with "1" being "not at all effective" and "6" being "extremely effective". NRT, nicotine replacement therapy; GP, general practitioner.

Quebec study which demonstrated that while many physicians discussed tobacco addiction with their patients in two years of seeing them [24], a significant minority perceived that these interventions took too much time or were not effective [25]. As knowledge-based learning is cultivated and reinforced through clinical observation, it is important that practicing physicians model the appropriate attitudes and actions towards tobacco use [26]. Although medical students from different countries agreed on the dangers of tobacco use, they differed in their perception of effective cessation methods. While medical students in London and Edmonton rated pharmacotherapy as more effective than physician advice, willpower or alternative therapy, and perceived "group cessation programs including nicotine replacement therapy (NRT)" to be the most effective tobacco cessation intervention, German medical students viewed "willpower alone" to be extremely effective [11]. Though advice from a physician doubles a smoker's chances of quitting [27], the majority of students from medical schools in Canada, Britain and Germany viewed "GP advice" as ineffective [11]. Despite their confidence in counseling and medicating tobacco users, this view may discourage clinical students at the University of Alberta from offering appropriate advice to current smokers.

Limitations

A self-administered survey is a convenient and effective way to measure knowledge and opinions but has inherent drawbacks. Our survey was only able to measure education and competency subjectively, relying on students to report on these parameters accurately. Objective measures of clinical competency must be sought through other modalities. Within these constraints, we took steps to ensure that the data we did obtain were of optimal quality by developing clear and concise wording and placement of question items and providing a logical flow to reduce respondent bias, burden and the length of the survey instrument. Heerwegh and Looseveldt [28] found that, when comparing data quality in face-to-face versus on-line survey responses, those who responded on a web survey were more inclined to opt for "don't know" responses. To minimize this effect, our survey instrument contained only one item with a "don't know" response category. The use of on-line surveys has been found to increase reporting of sensitive issues (like smoking behavior), increase the accuracy of reporting and decrease the likelihood of a question being skipped compared to other methods of data collection, especially among young, well-educated and computer literate populations [29].

A response rate of 44.2% is well within an acceptable range for online surveys of medical students. For example, a one-week survey of New York medical students resulted in a 30% response rate [30]; a 25-week mixed mode survey of Canadian physicians and medical students produced an email response rate of 29.9% [31] and an online survey of fourth-year medical students enrolled in six schools in New York City, which ran for 13.5 weeks, garnered a response rate of 50% [12]. Response rates were not uniform across the University of Alberta medical classes. Conclusions, especially those concerning the class of 2012, must be interpreted with caution. Our overall data suggest that there may be room for improvement in tobacco cessation intervention training. As the sampling frame was limited to one university, it may not be representative of medical education in all of Canada. Nonetheless, given the limited numbers of medical schools in Canada and the standardization of medical curriculum through licensing exams, we can assume that some of these findings may be relevant to other Canadian institutions.

Conclusions

University of Alberta medical students have lower cigarette smoking rates than students in Europe but seem to use cigars and waterpipes quite frequently. They are knowledgeable about the health consequences of tobacco addiction but still require education on the practical aspects of the treatment of tobacco addiction.

Practice implications

Although cigarettes have been the main focus of tobacco education, students and physicians must not overlook other forms of tobacco use such as cigars, cigarillos or waterpipes. Further analysis of both student and physician awareness of alternative tobacco use will inform continuing education on the subject and updated guidelines for the treatment of tobacco use. Additional training on behavior modification therapy and the effect of physician advice on patient behavior is also needed to address an overemphasis on pharmacotherapy. As medical students learn from a combination of didactic lectures, interactive exercises, and mentor role modeling, regular practice of preventative behavioral change interventions amongst physician preceptors can teach future physicians to employ this method as well. An evaluation of recent graduates in clinical practice will provide further clues into the longterm effectiveness of current tobacco medical education. Medical students and current physicians would benefit from the tools, support and ongoing education to make them effective leaders in tobacco cessation and health promotion.

Competing interests TR has received honoraria from Pfizer W , Novartis W , Glaxo Smith Kline W , Astra Zeneca W and Roche W as a speaker in activities related to continuing medical education. All other authors have none to declare.

Table 1
1Demographic characteristics of University of Alberta medical student respondentsn/N
%

Gender

Female
155/301
51.5

Male
146/301
48.5

Class

2015
111/301
36.9

2014
77/301
25.6

2013
70/301
23.3

2012
43/301
14.3

Smoking status

Cigarettes (ever)
90/301
29.9

Cigarettes (current)
10/301
3.3

Cigars/Cigarillos (ever)
122/301
40.5

Cigars/Cigarillos (current)
20/301
6.6

Waterpipe (ever)
120/301
39.9

Waterpipe (current)
18/301
6.0

Mean (SD)

Age [years]
24.4 (2.8)
21-47

Table 2
2Waterpipe smoking practices and beliefs among University of Alberta medical respondentsWaterpipe
Trend

Smokers
Non-smokers
χ2
p-value
χ2
p-value

http://www.tobaccoinduceddiseases.com/content/11/1/9
AcknowledgementsThe authors would like to thank Jodi Wolfe from Addiction and Mental Health Research Lab (AMHRL), School of Public Health, University of Alberta, for her contribution in online survey design and execution and Andrea Werner-Leonard, PhD who provided consulting services on study design.Authors' contributions AV carried out the survey, collected and analyzed data, and drafted the article with input from other authors. FH was instrumental in survey development, drafted the introduction and methods for ethics review, assisted in data analysis and provided critical revisions to the article. AC contributed to survey development, submitted the study for ethics approval, directed survey implementation and contributed to the methods section. CW assisted in question design and data interpretation. TR assisted in the design of the study, interpretation of the results and contributed to the discussion of the findings. BF is the principal investigator, responsible for the study conception, design, data interpretation and editorial revisions. All authors read and approved the final manuscript.
Canadian Medical Association: The role of physicians in prevention and health promotion. CMAJ. 19952208Canadian Medical Association: The role of physicians in prevention and health promotion. CMAJ 1995, 153(2):208A-D.

The impact of tobacco cessation training of medical students on their attitude towards smoking. S Yentz, R J Klein, A L Oliverio, Med Teach. 3411Yentz S, Klein RJ, Oliverio AL, et al: The impact of tobacco cessation training of medical students on their attitude towards smoking. Med Teach 2012, 34:11.

Physician smoking status, attitudes toward smoking, and cessation advice to patients: an international survey. A Pipe, M Sorensen, R Reid, Patient Educ Couns. 741Pipe A, Sorensen M, Reid R: Physician smoking status, attitudes toward smoking, and cessation advice to patients: an international survey. Patient Educ Couns 2009, 74(1):118-23.

Predictors of Canadian physicians' prevention counseling practices. E Frank, C Segura, H Shen, Can J Publ Health. 1015Frank E, Segura C, Shen H, et al: Predictors of Canadian physicians' prevention counseling practices. Can J Publ Health 2010, 101(5):390-5.

Correlates of physicians' preventionrelated practices. Findings from the Women Physicians' Health Study. E Frank, R Rothenberg, C Lewis, Arch Fam Med. 94Frank E, Rothenberg R, Lewis C, et al: Correlates of physicians' prevention- related practices. Findings from the Women Physicians' Health Study. Arch Fam Med 2000, 9(4):359-67.

Predictors of US medical students' prevention counseling practices. E Frank, J S Carrera, L Elon, Prev Med. 441Frank E, Carrera JS, Elon L, et al: Predictors of US medical students' prevention counseling practices. Prev Med 2007, 44(1):76-81.

Basic skills for working with smokers: a pilot test of an online course for medical students. M J White, B M Ewy, J Ockene, J Cancer Ed. 224White MJ, Ewy BM, Ockene J, et al: Basic skills for working with smokers: a pilot test of an online course for medical students. J Cancer Ed 2007, 22(4):254-8.

Behavior change counseling curricula for medical trainees: a systematic review. K E Hauer, P A Carney, A Chang, Acad Med. 877Hauer KE, Carney PA, Chang A, et al: Behavior change counseling curricula for medical trainees: a systematic review. Acad Med 2012, 87(7):956-68.

The perceptions and habits of alcohol consumption and smoking among Canadian medical students. S Thakore, Z Ismail, S Jarvis, Acad Psych. 333Thakore S, Ismail Z, Jarvis S, et al: The perceptions and habits of alcohol consumption and smoking among Canadian medical students. Acad Psych 2009, 33(3):193-7.

Canadian and English students' beliefs about waterpipe smoking: a qualitative study. J Roskin, P Aveyard, BMC Publ Health. 910Roskin J, Aveyard P: Canadian and English students' beliefs about waterpipe smoking: a qualitative study. BMC Publ Health 2009, 9:10.

Medical students lack basic knowledge about smoking: findings from two European medical schools. T Raupach, L Shahab, S Baetzing, Nicotine Tobacco Res. 111Raupach T, Shahab L, Baetzing S, et al: Medical students lack basic knowledge about smoking: findings from two European medical schools. Nicotine Tobacco Res 2009, 11(1):92-8.

Do medical students know enough about smoking to help their future patients? Assessment of New York City fourth-year medical students' knowledge of tobacco cessation and treatment for nicotine addiction. C M Springer, Tannert Niang, K M Matte, T D , Acad Med. 8310Springer CM, Tannert Niang KM, Matte TD, et al: Do medical students know enough about smoking to help their future patients? Assessment of New York City fourth-year medical students' knowledge of tobacco cessation and treatment for nicotine addiction. Acad Med 2008, 83(10):982-9.

German medical students lack knowledge of how to treat smoking and problem drinking. L Strobel, N K Schneider, H Krampe, Addiction. 201210Strobel L, Schneider NK, Krampe H, et al: German medical students lack knowledge of how to treat smoking and problem drinking. Addiction 2012, 107(10):1878-82.

World Health Organization: Tobacco Control Country Profiles. World Health Organization: Tobacco Control Country Profiles. http://www. who.int/tobacco/surveillance/policy/country_profile/en/index.html.

Canadian Tobacco Use Monitoring Survey (CTUMS): Summary of Annual Results for. Canadian Tobacco Use Monitoring Survey (CTUMS): Summary of Annual Results for 2011. 2012. http://www.hc-sc.gc.ca/hc-ps/tobac-tabac/research- recherche/stat/ctums-esutc_2011-eng.php.

The global epidemic of waterpipe smoking. W Maziak, Addict Behav. 361-2Maziak W: The global epidemic of waterpipe smoking. Addict Behav 2011, 36(1-2):1-5.

Exemptions for hookah bars in clean indoor air legislation: a public health concern. Public Health Nurs. D Noonan, 27Noonan D: Exemptions for hookah bars in clean indoor air legislation: a public health concern. Public Health Nurs 2010, 27(1):49-53.

Patterns of waterpipe use and dependence: implications for intervention development. W Maziak, T Eissenberg, K D Ward, Pharmacol Biochem Behav. 801Maziak W, Eissenberg T, Ward KD: Patterns of waterpipe use and dependence: implications for intervention development. Pharmacol Biochem Behav 2005, 80(1):173-9.

Interventions for promoting smoking cessation during pregnancy. J Lumley, C Chamberlain, T Dowswell, Cochrane Database Syst Rev. 331055Lumley J, Chamberlain C, Dowswell T, et al: Interventions for promoting smoking cessation during pregnancy. Cochrane Database Syst Rev 2009, 3(3):CD001055.

Prenatal and passive smoke exposure and incidence of asthma and wheeze: systematic review and meta-analysis. H Burke, J Leonardi-Bee, A Hashim, Pediatrics. 20124Burke H, Leonardi-Bee J, Hashim A, et al: Prenatal and passive smoke exposure and incidence of asthma and wheeze: systematic review and meta-analysis. Pediatrics 2012, 129(4):735-44.

Hypertension guideline recommendations in general practice: awareness, agreement, adoption, and adherence. C Heneghan, R Perera, D Mant, Br J Gen Pract. 57545Heneghan C, Perera R, Mant D, et al: Hypertension guideline recommendations in general practice: awareness, agreement, adoption, and adherence. Br J Gen Pract 2007, 57(545):948-52.

Physicians' attitudes to the pharmacological treatment of patients with stable angina pectoris. M D Beaulieu, J Brophy, A Jacques, QJM. 981Beaulieu MD, Brophy J, Jacques A, et al: Physicians' attitudes to the pharmacological treatment of patients with stable angina pectoris. QJM 2005, 98(1):41-51.

Canadian Smoking Cessation Clinical Practice Guideline. Toronto, Canada: Canadian Action Network for the Advancement, Dissemination and Adoption of Practice-informed Tobacco Treatment, Centre for Addiction and Mental Health. Can-Adaptt, CAN-ADAPTT: Canadian Smoking Cessation Clinical Practice Guideline. Toronto, Canada: Canadian Action Network for the Advancement, Dissemination and Adoption of Practice-informed Tobacco Treatment, Centre for Addiction and Mental Health; 2011.

Do you counsel your patients on their health behaviors?. C Sauvageau, S Groulx, A Pelletier, Can J Public Health. 991Sauvageau C, Groulx S, Pelletier A, et al: Do you counsel your patients on their health behaviors? Can J Public Health 2008, 99(1):31-5.

General practitioners' and family physicians' negative beliefs and attitudes towards discussing smoking cessation with patients: a systematic review. F Vogt, S Hall, T M Marteau, Addiction. 10010Vogt F, Hall S, Marteau TM: General practitioners' and family physicians' negative beliefs and attitudes towards discussing smoking cessation with patients: a systematic review. Addiction 2005, 100(10):1423-31.

Knowledge gaps about smoking cessation in hospitalized patients and their doctors. T Raupach, J Merker, G Hasenfuss, Eur J Cardiovasc Prev Rehabil. 182Raupach T, Merker J, Hasenfuss G, et al: Knowledge gaps about smoking cessation in hospitalized patients and their doctors. Eur J Cardiovasc Prev Rehabil 2011, 18(2):334-41.

Physician advice for smoking cessation. L F Stead, G Bergson, T Lancaster, Cochrane Database Syst Rev. 22165Stead LF, Bergson G, Lancaster T: Physician advice for smoking cessation. Cochrane Database Syst Rev 2008, 2(2):CD000165.

Face-to-face versus web surveying in a highinternet-coverage population. D Heerwegh, G Loosveldt, Public Opin Q. 725Heerwegh D, Loosveldt G: Face-to-face versus web surveying in a high- internet-coverage population. Public Opin Q 2008, 72(5):836-46.

Social desirability bias in CATI, IVR and web surveys: The effects of mode and question sensitivity. F Kreuter, S Presser, R Tourangeau, Public Opin Q. 725Kreuter F, Presser S, Tourangeau R: Social desirability bias in CATI, IVR and web surveys: The effects of mode and question sensitivity. Public Opin Q 2008, 72(5):847-65.

A survey of knowledge, attitudes, and beliefs of medical students concerning antimicrobial use and resistance. M T Minen, D Duquaine, M A Marx, Microb Drug Resist. 164Minen MT, Duquaine D, Marx MA, et al: A survey of knowledge, attitudes, and beliefs of medical students concerning antimicrobial use and resistance. Microb Drug Resist 2010, 16(4):285-9.

Effects of various methodologic strategies: survey response rates among Canadian physicians and physicians-in-training. Can Fam Phys. I Grava-Gubins, S Scott, 10.1186/1617-9625-11-954Grava-Gubins I, Scott S: Effects of various methodologic strategies: survey response rates among Canadian physicians and physicians-in-training. Can Fam Phys 2008, 54(10):1424-30. doi:10.1186/1617-9625-11-9

Submit your next manuscript to BioMed Central and take full advantage of: • Convenient online submission • Thorough peer review • No space constraints or color figure charges • Immediate publication on acceptance • Inclusion in PubMed, CAS, Scopus and Google Scholar • Research which is freely available for redistribution. Vanderhoek, Tobacco Induced Diseases. 119Future physicians and tobacco: an online survey of the habits, beliefs and knowledge base of medical students at a Canadian University. Submit your manuscript at www.biomedcentral.com/submitCite this article as: Vanderhoek et al.: Future physicians and tobacco: an online survey of the habits, beliefs and knowledge base of medical students at a Canadian University. Tobacco Induced Diseases 2013 11:9. Submit your next manuscript to BioMed Central and take full advantage of: • Convenient online submission • Thorough peer review • No space constraints or color figure charges • Immediate publication on acceptance • Inclusion in PubMed, CAS, Scopus and Google Scholar • Research which is freely available for redistribution Submit your manuscript at www.biomedcentral.com/submit