Abortifacient effect and uterine cervix-dilating action of 16, 16-dimethyl trans delta 2 PGE1 methyl ester (ONO 802) in the form of a vaginal suppository (a randomized, double-blind, controlled study in the second trimester of pregnancy).

A newly synthesized 16, 16-dimethyl trans delta 2 PGE1 methyl ester (ONO 802) was clinically applied in the form of a vaginal suppository for therapeutic abortion of second trimester pregnancies. Its effects were studied in a double-blind test comparing it with an inactive placebo suppository. The study was conducted at 12 Japanese university hospitals. The number of patients was 125 in total, i.e. 63 receiving ONO 802 vaginal suppository (containing 1.0 mg ONO 802) and 62 receiving inactive placebo suppository. ONO 802 was more effective than placebo with a success rate of 87% (complete (71%) and incomplete (16%) abortions). The onset of uterine contractions was observed in 154.3+/-18.1 min. and the onset of uterine bleeding in 323.6+/-41.0 min. The expulsion of the fetus and placenta was observed in 955.4+/-97.0 and 961.6+/-97.0 min., respectively. The cervix dilating effect of ONO 802 was observed in 63.5% of the patients at 3 hours after the start of administration. Nausea, vomiting, abdominal cramps, diarrhea and pyrexia were noticed. However, all these side effects were transient and mild, requiring no treatment. No abnormality was observed in the puerperal course, duration of uterine bleeding or onset of subsequent menstruation following the therapeutic abortion. Therefore, the present study demonstrated that ONO 802 vaginal suppository was an effective and valuable drug for therapeutic abortion of second trimester pregnancies.