Women’s Health · Clinical trials
Preterm Labour Clinical Trials
Approved therapies, the pivotal-trial endpoints they were judged on, the magnitude of benefit — and the drugs that failed their endpoints, and why.
Indication overview
About preterm labour — and why its trials are hard
Preterm labour is regular uterine contractions with cervical change before 37 weeks' gestation, the leading driver of neonatal morbidity and mortality worldwide. Pharmacotherapy is notably limited: there is currently no FDA-approved drug that reliably prevents recurrent preterm birth or safely arrests active preterm labour. Tocolytics such as nifedipine (a calcium-channel blocker), indomethacin (an NSAID), and the beta-agonist terbutaline are used off-label to delay delivery by roughly 48 hours, chiefly to permit antenatal corticosteroid administration and maternal transfer, not to improve neonatal outcomes. The oxytocin-receptor antagonist atosiban is approved in Europe but never in the US. The signal event in the field is the 2023 FDA withdrawal of hydroxyprogesterone caproate (Makena) after the confirmatory PROLONG trial failed to reproduce benefit. As a result, prevention now relies on vaginal progesterone in selected women, cervical cerclage, and cervical pessary. The therapeutic void reflects incomplete understanding of parturition biology and stringent safety demands of maternal-fetal drug development.
Where trials have failed
Drugs that missed their endpoint — and what contributed
The most instructive lessons in preterm labour development come from programmes that failed the endpoint that mattered.
| Drug / trial | Endpoint outcome | What contributed |
|---|---|---|
| Hydroxyprogesterone caproate (Makena) — PROLONG (confirmatory postmarketing trial, results 2019) | Failed to reduce recurrent preterm birth (<35 weeks) or improve the neonatal composite morbidity/mortality index versus placebo; no significant separation. FDA proposed withdrawal in 2020 and formally withdrew approval in April 2023. | Original 2011 accelerated approval rested on a single smaller trial (Meis 2003) with an anomalously high placebo-group event rate; the larger, more geographically diverse PROLONG population showed no benefit, suggesting the initial result was not reproducible. |
| Retosiban (GSK221149A, oxytocin-receptor antagonist) — Phase 3 programme (e.g., NCT02377466) for spontaneous preterm labour | GSK discontinued the phase 3 development programme in 2017; trials were terminated without demonstrating benefit, driven largely by infeasible enrollment. | Very slow recruitment, narrow eligibility windows in acute preterm labour, and portfolio prioritisation; the oxytocin-antagonist class has not delivered improved neonatal outcomes. (Efficacy conclusions unverified due to early termination.) |
Choosing the right endpoint
Primary endpoints that matter in preterm labour trials
- Recurrent preterm birth < 35 weeks — Primary efficacy endpoint used in PROLONG/Makena; a clinically meaningful gestational-age threshold for neonatal morbidity.
- Neonatal morbidity/mortality composite index — Co-primary in PROLONG, capturing the outcomes that actually matter beyond delivery timing.
- Delay of delivery by 48 hours / 7 days — Standard tocolysis endpoint; sufficient to complete antenatal corticosteroids and arrange transfer, but not linked to improved neonatal survival.
- Gestational age at delivery — Continuous surrogate; longer latency does not guarantee better outcomes.
How iNGENū runs preterm labour trials
Physician-led design, built for FDA submission
Endpoint & biomarker strategy
Board-certified specialists design endpoints and patient selection aligned to current FDA guidance for this indication.
FDA-ready data
Built to ICH-GCP and 21 CFR 312.120, with direct FDA submission — data accepted by the FDA, EMA and MHRA.
Faster, lower-cost delivery
~4-week ethics via the TGA CTN scheme, up to 43.5% R&D rebate, and 80–90% below US CRO cost.
Request a fixed-milestone proposal and a tailored endpoint & feasibility summary for this indication.
Frequently asked questions
Preterm Labour clinical trials — FAQs
Is any drug FDA-approved to prevent or treat preterm labour?
Why was Makena withdrawn?
What are tocolytics actually for?
Ready to discuss your preterm labour trial?
Talk to our physician-led team about an FDA-ready, cost-efficient trial design.
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