Respiratory · Clinical trials
Obstructive Sleep Apnoea 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 obstructive sleep apnoea — and why its trials are hard
Obstructive sleep apnoea (OSA) is characterised by repetitive upper-airway collapse during sleep causing intermittent hypoxaemia, arousals and fragmented sleep, with daytime sleepiness and elevated cardiovascular risk. Severity is graded by the apnoea-hypopnoea index (AHI). For decades there was no approved pharmacotherapy for the underlying disorder: continuous positive airway pressure (CPAP) remained the standard of care, supplemented by mandibular devices, positional therapy, weight loss and, in selected patients, hypoglossal nerve stimulation. Numerous drugs (SSRIs, protriptyline, mirtazapine, and various respiratory stimulants) were tested and failed to produce clinically meaningful AHI reductions. The landmark change came in December 2024, when tirzepatide (Zepbound), a dual GIP/GLP-1 receptor agonist, became the first drug ever approved for moderate-to-severe OSA in adults with obesity, on the basis of the SURMOUNT-OSA programme showing large AHI reductions. Separately, solriamfetol (Sunosi) is approved to treat residual excessive daytime sleepiness in OSA but does not treat the apnoea itself.
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 |
|---|---|---|---|---|---|
| Tirzepatide (Zepbound) | 2024 | First-ever drug for moderate-to-severe OSA in adults with obesity (with diet and exercise) | SURMOUNT-OSA (phase 3, two studies: with and without concurrent CPAP) | Change in apnoea-hypopnoea index (AHI) at week 52 | AHI reduced by approximately 20-25 events/hour (roughly 50-63% relative reduction) versus placebo; landmark first pharmacologic approval for OSA |
| Solriamfetol (Sunosi) | 2019 | Excessive daytime sleepiness (residual) in adults with OSA; does not treat the apnoea | TONES 3 (phase 3) | Change in Maintenance of Wakefulness Test (MWT) sleep latency and Epworth Sleepiness Scale (ESS) at week 12 | Significant improvement in MWT latency and reduction in ESS versus placebo (dose-dependent, p<0.001) |
Where trials have failed
Drugs that missed their endpoint — and what contributed
The most instructive lessons in obstructive sleep apnoea development come from programmes that failed the endpoint that mattered.
| Drug / trial | Endpoint outcome | What contributed |
|---|---|---|
| Mirtazapine (and earlier agents such as protriptyline, SSRIs, respiratory stimulants) — Small randomised crossover/controlled trials of pharmacotherapy for OSA | No clinically meaningful, durable reduction in AHI; not viable as OSA disease-modifying therapy | Incomplete understanding of collapse mechanisms, off-target effects (weight gain, sedation) and poor tolerability; underpowered studies |
Choosing the right endpoint
Primary endpoints that matter in obstructive sleep apnoea trials
- Apnoea-Hypopnoea Index (AHI) — Events per hour of sleep; the primary polysomnographic efficacy endpoint in OSA trials
- Oxygen desaturation index / hypoxic burden — Captures severity of nocturnal hypoxaemia linked to cardiovascular risk
- Epworth Sleepiness Scale (ESS) — Patient-reported subjective daytime sleepiness
- Maintenance of Wakefulness Test (MWT) — Objective measure of ability to stay awake, used for residual sleepiness endpoints
- Body weight / patient-reported outcomes — Secondary endpoints relevant to obesity-driven OSA (e.g., SURMOUNT-OSA)
How iNGENū runs obstructive sleep apnoea 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
Obstructive Sleep Apnoea clinical trials — FAQs
Is there an FDA-approved drug for OSA?
Does tirzepatide replace CPAP?
What does solriamfetol treat?
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