Psychiatry · Clinical trials
Insomnia Disorder 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 insomnia disorder — and why its trials are hard
Insomnia Disorder involves persistent difficulty initiating or maintaining sleep with daytime impairment, despite adequate opportunity to sleep. Cognitive behavioral therapy for insomnia (CBT-I) is first-line, but several FDA-approved pharmacotherapies exist across mechanisms. The non-benzodiazepine 'Z-drugs,' led by zolpidem (Ambien, 1992), act on GABA-A receptors and remain widely used for sleep onset and maintenance. Ramelteon (Rozerem, 2005) is a melatonin MT1/MT2 receptor agonist targeting sleep onset with a favorable non-scheduled profile. The newest and fastest-growing class is dual orexin receptor antagonists (DORAs), which promote sleep by blocking wake-promoting orexin signaling: suvorexant (Belsomra, 2014), lemborexant (Dayvigo, 2019), and daridorexant (Quviviq, 2022). DORAs improve both sleep onset and maintenance with objective polysomnography endpoints and are Schedule IV. Historic failures include almorexant, an early DORA discontinued in 2011 over tolerability and safety concerns. The therapeutic landscape now balances efficacy against next-day residual effects, dependence, and safety, with DORAs positioned as a lower-risk maintenance option than older sedative-hypnotics.
Approved therapies & pivotal evidence
What's been approved — and by how much it moved the endpoint
| Drug (brand) | Approved | Setting | Pivotal trial | Primary endpoint | Magnitude of benefit |
|---|---|---|---|---|---|
| Zolpidem (Ambien / Ambien CR) | 1992 (immediate-release); 2005 (controlled-release) | Short-term treatment of insomnia (sleep onset; CR adds maintenance) | Registration RCTs; controlled-release program (Krystal et al.) | Latency to persistent sleep / wake after sleep onset (PSG and subjective) | Significant reductions in sleep-onset latency vs placebo; CR formulation improved sleep maintenance in early-night hours |
| Ramelteon (Rozerem) | 2005 | Insomnia characterized by difficulty with sleep onset (non-scheduled) | Zammit et al. and pivotal RCTs | Latency to persistent sleep (PSG) | Modest but significant reduction in sleep-onset latency vs placebo; no abuse liability, so not a controlled substance |
| Suvorexant (Belsomra) | 2014 | Insomnia with sleep-onset and/or sleep-maintenance difficulty (dual orexin antagonist) | Phase 3 program (Herring et al.) | Subjective total sleep time and time to sleep onset; PSG WASO | Significant improvements in subjective TST and sleep onset vs placebo; reductions in wake after sleep onset |
| Lemborexant (Dayvigo) | 2019 | Insomnia with sleep-onset and/or maintenance difficulty (dual orexin antagonist) | SUNRISE-1 (vs placebo and zolpidem ER) and SUNRISE-2 | PSG sleep-onset latency (LPS) and sleep efficiency / WASO | Superior to placebo on sleep onset and maintenance; SUNRISE-1 showed benefit on sleep efficiency vs both placebo and zolpidem ER |
| Daridorexant (Quviviq) | 2022 | Insomnia with sleep-onset and/or maintenance difficulty (dual orexin antagonist) | Phase 3 (Mignot et al., Lancet Neurology 2022; Study 1/NCT03545191) | Change in WASO and LPS at months 1 and 3; subjective TST and daytime functioning (IDSIQ) | 50 mg significantly reduced WASO (~-29 min vs placebo change) and LPS, improved subjective TST, and improved daytime sleepiness/functioning |
Where trials have failed
Drugs that missed their endpoint — and what contributed
The most instructive lessons in insomnia disorder development come from programmes that failed the endpoint that mattered.
| Drug / trial | Endpoint outcome | What contributed |
|---|---|---|
| Almorexant — Phase 3 RESTORA/development program (Actelion/GSK), discontinued 2011 | Failed to reach market — clinical development discontinued despite efficacy signals | Tolerability and safety concerns (including liver-enzyme/emergent safety signals) led sponsors to halt the first dual orexin antagonist |
| Filorexant — Merck phase 2 development | Discontinued — did not advance to approval | Insufficient differentiation/efficacy-safety balance to justify further development among competing DORAs |
Choosing the right endpoint
Primary endpoints that matter in insomnia disorder trials
- Latency to persistent sleep (LPS) — Objective PSG measure of how quickly sleep is initiated; key onset endpoint
- Wake after sleep onset (WASO) — Objective maintenance endpoint central to DORA approvals (e.g., daridorexant, lemborexant)
- Subjective total sleep time (sTST) — Patient-reported outcome required for meaningful clinical benefit
- Daytime functioning (e.g., IDSIQ) — Daridorexant's demonstration of daytime benefit differentiated it and reflects evolving regulatory expectations
How iNGENū runs insomnia disorder 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
Insomnia Disorder clinical trials — FAQs
What is first-line for chronic insomnia?
How are orexin antagonists (DORAs) different from Z-drugs?
Why did almorexant fail if orexin drugs now work?
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