Recombinant anti-D for prevention of maternal-foetal Rh(D) alloimmunization: a randomized multi-centre clinical trial

OBJECTIVE: To compare the efficacy and safety of recombinant anti-D (R-anti-D) with conventional polyclonal anti-D (Poly anti-D) in preventing maternal-fetal rhesus D (RhD) alloimmunization and to investigate the immunogenicity of R-anti-D. METHODS: This was a randomized, open-label, multi-center clinical trial conducted in RhD-negative pregnant women who did not receive antenatal anti-D who delivered RhD-positive babies and showed negative indirect Coombs tests (ICTs) at baseline. The women were randomized in a 2:1 ratio to R-anti-D or Poly anti-D groups and were administered 300 mcg (IM) of the corresponding drug within 72 hours of delivery. ICT was performed 72 hours, 90 days, and 180 days after anti-D injection. Serum samples were collected to check for the development of antibodies against R-anti-D at days 90 and 180, using bridging enzyme-linked immunosorbent assay. The proportion of subjects who had positive ICT results at days 90 and 180 were compared between the groups using Fisher's exact test. RESULTS: A total of 144 women were randomized to the R-anti-D group and 71 to the Poly anti-D group. Three women in the R-anti-D and none in the Poly anti-D group had a positive ICT result at day 90. No woman in either group had positive ICT result at day 180. Both drugs were well tolerated with only 4 reports of adverse events in each group—all were mild, non-serious, and resolved without sequelae. No subject developed antibodies against R-anti-D. CONCLUSION: The studied R-anti-D is comparable in efficacy to conventional Poly anti-D and is safe and non-immunogenic. TRIAL REGISTRATION: Clinical Trials Registry of India Identifier: TRIAL REGISTRATION: Clinical Trials Registry of India Identifier: CTRI/2017/03/008101