Traitement médical des grossesses extra-utérines : un essai clinique randomisé comparant méthotrexate-mifépristone et placebo-méthotrexate

Abstract

Medical treatment of ectopic pregnancy is widespread. To increase the efficacy of methotrexate, combination with mifepristone has been proposed. We performed a large prospective multicentre double-blind sequential randomized trial in order to compare the efficacy of methotrexate and mifepristone (600 mg given orally) versus methotrexate and placebo. Two hundred twelve ectopic pregnancies were randomized. There was no significant difference in the initial characteristics between the 2 groups. There was no significant difference in the success rate of medical treatment between the methotrexate-mifepristone (n=113) and the methotrexate-placebo group (n=99): 79.6% (90/113) vs 74.2% (72/97) respectively, RR [95% CI]: 1.07 [0.92-1.25], p=0.41. However, there was a quantitative interaction between progesterone level and effect of treatment: when progesterone level was 10 ng/l, the efficacy of the combination of mifepristone and methotrexate was significantly higher than the combination of methotrexate and placebo, with a 83.3% success rate (15/18) vs 38.5% (5/13) respectively. Our study failed to demonstrate any benefit of the addition of mifepristone to methotrexate. By contrast, the quantitative interaction between treatment effect and base line serum progesterone suggested that this combination could be reserved to ectopic pregnancies associated with high serum progesterone concentrations.