Efficacy and safety of a new, chromatographically purified rhesus (D) immunoglobulin. [Ante-partum administration of preventive treatment of Rh-D immunization in rhesus-negative women. Parallel evaluation of transplacental passage of fetal blood cells. Results of a multicenter study carried out in the Paris region].
To study the efficacy, safety, and tolerability of the 300 microg dose of a new chromatographically produced rhesus immunoglobulin (Rhophylac 300) for ante- and postnatal rhesus prophylaxis.
                In an open-label multi-centre study, rhesus D (RhD)-negative women were randomly allocated to receive Rhophylac 300 either intravenously or intramuscularly at the 28th week of gestation and within 72 h after delivery of an RhD-positive child. Serum samples were obtained prior to the antenatal dose and 6-11.5 months after delivery of an RhD-positive child and tested by the indirect antiglobulin test and papain test for anti-D. Safety parameters were assessed in all women who were treated with the study drug.
                Four hundred and thirty two women received the study drug antenatally. No differences were detected in efficacy or tolerability between intravenous and intramuscular administration. Of the 261 women who delivered an RhD-positive child and received rhesus prophylaxis according to the protocol, 248 women returned for follow-up investigations. None of them had detectable anti-D at their last visit. There were no serious adverse events, no cases of infectious disease transmission nor clinically relevant changes in laboratory safety values and vital signs attributable to the study drug.
                The results suggest that Rhophylac 300 given intravenously or intramuscularly is safe and efficacious in preventing rhesus (D) immunisation. 1,969 non immunized rhesus negative primiparous women were followed up in 23 maternity units in the geographical region of Paris. 1,882 could be retained to study antepartum protection and 1,884 to study transplacental passage of fetal blood cells. Two groups were defined according to whether they were born in even or uneven years, so that: 955 were the "control" group who delivered 590 rhesus D positive infants, and 927 were the "treated" group who delivered 599 rhesus D positive infants. The "control" group were used as controls at the 28th and 34th weeks of pregnancy, while the "treated" group received two injections of anti-D immunoglobulin given on the same dates after taking the necessary tests. Immunological testing at the time of the delivery and after the delivery showed that 7 women had become Rh D immunized in the "control" group whereas only one in the "treated" group. This difference, which is statistically significant, confirms the results of other authors about the efficiency of antepartum rhesus disease prevention. The incidence of immunisation during or immediately after the first pregnancy in women who had no previous story of blood transfusions or of terminations of pregnancy is 1.11%, which is a figure relatively low as compared with studies of series carried out in North America, but close to those carried out in other European centres. When primipara of all categories are lumped together the frequency rises to 1.5%. A study of the passage of fetal red blood cells into the maternal circulation shows that at the 29th week of pregnancy out of 1,884 cases there were 5.5% positive kleihauer tests, without a large volume of blood being detected and at the 34th week of pregnancy when 957 tests were carried out, 7% were positive with one of them being of a massive transfusion of blood from the fetus to the mother, which was life-threatening for the fetus. It may be that the incidence had been under-estimated and that the positive results in the two groups, control and treated, show that there is a statistically significant difference that demonstrates that antepartum treatment in the trial has eliminated a worthwhile percentage of positive kleihauer tests which arose from the transfusion of small quantities of blood.(ABSTRACT TRUNCATED AT 400 WORDS)
The risk of Rhesus D alloimmunisation during or immediately after a first pregnancy is about 1%. Administration of 100 µg (500 IU) anti-D to women in their first pregnancy can reduce this risk to about 0.2% without, to date, any adverse effects. Although unlikely to confer benefit in the current pregnancy, fewer women may have Rhesus D antibodies in any subsequent pregnancy, but the effects of this needs to be tested in studies of robust design.