Treatment of spontaneous preterm labour with retosiban: a phase 2 proof-of-concept study
British Journal of Clinical Pharmacology
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AIM: To investigate the efficacy and safety of intravenous retosiban in women with spontaneous preterm labour. METHODS: Randomised, double-blind, placebo-controlled, phase 2 trial. Retosiban was administered intravenously for 48 hours to women in spontaneous preterm labour between 30(0/7) and 35(6/7) weeks' gestation with an uncomplicated singleton pregnancy in an in-patient obstetric unit. Outcome measures were uterine quiescence (primary endpoint), days to delivery, preterm delivery, and safety. RESULTS: Uterine quiescence was achieved in 62% of women who received retosiban (n = 30) compared with 41% who received placebo (n = 34). The relative risk (RR) was 1.53 (95% credible interval [CrI]: 0.98, 2.48; NS). Retosiban resulted in a significant increase in time to delivery compared with placebo (mean difference, 8.2 days; 95% CrI: 2.7, 13.74); this difference was consistent across all gestational ages. The proportion of preterm births in the retosiban and placebo groups was 18.7% (95% CrI: 7.4%, 33.7%) and 47.2% (95% CrI: 31.4%, 63.4%), respectively. The RR of preterm birth in women treated with retosiban was 0.38 (95% CrI: 0.15, 0.81). There were no deliveries within 7 days in the retosiban group, but there were six (17.6%) births in the placebo group. Maternal, fetal, and neonatal adverse events were similar in the retosiban and placebo groups. CONCLUSIONS: Intravenous administration of retosiban in women with spontaneous preterm labour was associated with a greater than 1-week increase in time to delivery compared with placebo, a significant reduction in preterm deliveries, a non-significant increase in uterine quiescence, and a favourable safety profile.
This is the peer reviewed version of the article which has been published in final form at doi: 10.1111/bcp.12646. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.
Vol. 80 (4), pp. 740–749