Safety study of tirilazad mesylate in patients with acute ischemic stroke (STIPAS). A randomized, double-blind, vehicle-controlled trial of tirilazad mesylate in patients with aneurysmal subarachnoid hemorrhage: a cooperative study in North America.
Tirilazad mesylate, a 21-amino-steroid, is a potent membrane lipid peroxidation inhibitor and free radical scavenger that has shown promise in animal models of focal cerebral ischemia. Safety in patients with acute ischemic stroke has not yet been established.
                The study comprised a randomized (three drugs to one vehicle), vehicle-controlled, double-blind, sequential dose-escalation trial at five centers. Treatment was begun within 12 hours of stroke onset and was continued intravenously for 3 days.
                One hundred eleven patients (mean +/- SD age, 66 +/- 13 years; 56% male) were enrolled in three successive dosage tiers: 36 at 0.6 mg/kg per day, 35 at 2.0 mg/kg per day, and 40 at 6.0 mg/kg per day. Median time from stroke onset to treatment was 8.5 (range, 3 to 12) hours and was not significantly different among the groups. Tirilazad was well tolerated at all three doses, except for mild-to-moderate injection site irritation that occurred in both the tirilazad- and vehicle-treated groups. No significant differences in measures of either cardiac or hepatic toxicity were observed in this small sample. Imbalances in baseline medical and neurological condition made comparisons of outcome difficult. Although no evidence suggestive of tirilazad efficacy was apparent in this study, the trial was not designed to test for differences in outcome.
                These observations suggest that intravenous tirilazad at doses of up to 6.0 mg/kg per day for 3 days is well tolerated in this population of predominantly elderly stroke patients. Larger studies with earlier treatment will be needed to demonstrate efficacy. To test the safety and efficacy of tirilazad mesylate, a nonglucocorticoid 21-aminosteroid, in improving the outcome of patients with aneurysmal subarachnoid hemorrhage (SAH), 902 patients were enrolled in a prospective randomized, double-blind, vehicle-controlled trial at 54 North American neurosurgical centers. Five patients were excluded prior to receiving any study drug. Of 897 patients who received at least one dose of study medication, 300 received a placebo containing a citrate vehicle, 298 received 2 mg/kg per day tirilazad, and 299 received 6 mg/kg per day tirilazad, all administered intravenously beginning within 48 hours of the SAH and continuing through 10 days posthemorrhage. All patients were also treated with orally administered nimodipine. At 3 months post-SAH, there were no significant differences (p < 0.025) among the groups with regard to mortality rate, favorable outcome on the Glasgow Outcome Scale, or employment status. During the first 14 days after the SAH, there were no significant differences among the groups in the incidence or severity of clinically symptomatic or angiographically identifiable cerebral vasospasm. Mortality data stratified by gender and neurological grade on admission (assessed according to a modified World Federation of Neurological Surgeons scale) demonstrated that the men with Grades IV to V had a 33% mortality rate in the vehicle group, 52% in the 2 mg/kg per day tirilazad group (p = 0.29), and 5% in the 6 mg/kg per day tirilazad group (p = 0.03). Tirilazad was well tolerated at both dose levels. Tirilazad mesylate at dosage levels of up to 6 mg/kg per day for 8 to 10 days following SAH did not improve the overall outcome in patients with aneurysmal SAH in this trial. The differences in the efficacy of tirilazad in this trial and a previously reported trial in Europe, Australia, and New Zealand, in which dosage levels of tirilazad of 6 mg/kg per day reduced mortality rates and increased good recovery, may be a result of differences in admission characteristics of the patients and/or differences in management protocols, including the use of anticonvulsant medications.
Tirilazad mesylate increased the combined end-point of 'death or disability' by about one-fifth, but did not alter case fatality, when given to patients with acute ischaemic stroke. Although further trials of tirilazad are now not warranted, analysis of individual patient data from the trials may help elucidate why tirilazad appears to worsen outcome in acute ischaemic stroke.