Safety and Outcomes in Infants Born to Mothers Participating in Retosiban Treatment Trials: ARIOS Follow-up Study.

Objective: Retosiban, an oxytocin receptor antagonist, was developed for treating spontaneous preterm labor (sPTL) in women with intact membranes. This ARIOS follow-up study aimed to characterize clinical safety, morbidity, and mortality of infants exposed to retosiban or comparator over 2 years.

Study Design: ARIOS prospectively assessed outcomes in infants whose mothers received at least one dose of retosiban or comparator (placebo/atosiban) in two Phase 3 sPTL trials.

Randomized Trials of Retosiban Versus Placebo or Atosiban in Spontaneous Preterm Labor.

Objective: The aim of this study is to assess the efficacy and safety of retosiban in spontaneous preterm labor (sPTL).

Study Design: Two multicenter, randomized, and double-blind trials compared retosiban with placebo and retosiban with atosiban in women with a singleton pregnancy and intact membranes in sPTL at 24 to 33 weeks' gestation. Coprimary endpoints in the placebo-controlled trial were time to delivery (TTD) or treatment failure (whichever occurred first) and neonatal composite morbidity and mortality.

Treatment of spontaneous preterm labour with retosiban: a phase II pilot dose-ranging study.

Aims: The aims of the present study were to investigate the maternal, fetal and neonatal safety and tolerability, pharmacodynamics and pharmacokinetics of intravenous (IV) retosiban in pregnant women with spontaneous preterm labour (PTL) between 34 and 35  weeks' gestation.

Methods: In parts A and B of a three-part, double-blind, placebo-controlled, multicentre study, women were randomized 3:1 (Part A) or 2:1 (Part B) to either 12-h IV retosiban followed by a single dose of oral placebo (R-P) or 12-h IV placebo followed by single-dose oral retosiban (P-R).

Results: A total of 29 women were randomized; 20 to R-P and nine to P-R.

Treatment of spontaneous preterm labour with retosiban: a phase 2 proof-of-concept study.

Aim: The aim was to investigate the efficacy and safety of intravenous retosiban in women with spontaneous preterm labour.

Methods: This was a randomized, double-blind, placebo-controlled, phase 2 trial. Retosiban was administered intravenously for 48 h 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.