Axsome pushes SUSTAIN shift-work-disorder readout guidance from 2026 to 2027
The Phase 3 SUSTAIN trial's completion date has not moved, but Axsome's own Q1 2026 guidance now points to 2027, a signal the model's 98.5% endpoint read does not capture.
Executive Summary
- Axsome's Q1 2026 update guides topline SUSTAIN results to 2027, reversing six straight quarters of 2026 guidance, even though the registered primary completion date stays 2026-12-01 Press ReleasePress ReleaseAug 5, 2024. That gap between sponsor language and registry data is the operational fact investors need to track.
- SUSTAIN carries two co-primary endpoints, a CGI-S severity score and an MWT sleep-latency measure, tested against placebo in 520 patients. Both endpoints must be read together; a split result raises questions about which the FDA would treat as sufficient.
- AppliedXL's 98.5% endpoint-met read carries a LOW confidence label and leans on enrollment size and endpoint base rates rather than mechanism-specific evidence, while the model's own clinical-significance score sits at 49.6%. The two figures answer different questions and should not be conflated.
- No other Phase 3 trial studies TAAR-1 modulation in shift work disorder, and no prior TAAR-1 x shift-work-disorder trial has failed. That leaves SUSTAIN without a direct comparator or failure precedent to benchmark the result against.
The guidance gap
Axsome Therapeutics first told investors in an August 2024 earnings release that the SUSTAIN Phase 3 trial had just initiated, with topline results expected in 2026 Press ReleasePress ReleaseAug 5, 2024. That 2026 guidance repeated across five subsequent disclosures through November 2025, according to the guidance history tied to this catalyst. The company's Q1 2026 update changed that language, guiding instead to 2027 for topline results. The registered primary completion date for NCT06568367 has not moved and remains December 1, 2026. That combination, a slipping public guidance timeline against a stable registry completion date, is the fact investors should weigh most heavily against the model's readout-timing forecast.
Probability of SuccessBased on the AppliedXL Probability of Success model. For more information about the methodology, read the research here.
What SUSTAIN measures
SUSTAIN is a randomized, placebo-controlled Phase 3 trial enrolling 520 adults aged 18 to 65 who meet ICSD-3 criteria for shift work disorder. It carries two co-primary endpoints: change from baseline to Week 12 in the Clinical Global Impressions of Severity of Illness (CGI-S), a clinician-rated severity scale, for night-shift sleepiness, and change from baseline to Week 12 in mean sleep latency on the Maintenance of Wakefulness Test (MWT), an objective measure of the ability to stay awake. No endpoint results, effect sizes, or p-values exist yet; ClinicalTrials.gov shows no results posted for this trial. The trial is registrational, meaning a positive result is designed to support a regulatory filing rather than only inform further development.
What the model says and does not say
AppliedXL's endpoint-met probability stands at 98.5%, but that figure carries a LOW confidence label from the model itself. The driver mix behind that number leans heavily on endpoint-type historical success rates and enrollment-per-arm size, structural and operational features, rather than target-biology or mechanism-fit signals, several of which pull in the opposite direction. Separately, the model's clinical-significance score, which speaks to whether a statistically positive result would also be clinically meaningful, sits at 49.6%, near a coin flip. Investors should read the 98.5% figure as a statistical-bar estimate built mainly on structural and historical base rates, not as a forecast of a clinically differentiated result.
Competitive and franchise context
No other active Phase 3 trial tests TAAR-1 modulation in shift work disorder, and the target-indication pairing carries no recorded historical terminations, so there is no failure precedent to weigh against a SUSTAIN result. Solriamfetol is already FDA-approved as Sunosi for other sleep-related indications under NDA211230, and Axsome runs the same drug in Phase 3 trials for binge eating disorder and major depressive disorder. A positive SUSTAIN result would extend a molecule already on the market rather than validate an unproven mechanism, which raises the readthrough value to Axsome's broader solriamfetol strategy even without a head-to-head competitor.
This analysis was produced using AI-assisted reporting systems, AppliedXL data, and official public records. These systems undergo editorial review, quality checks, and regular audits by human experts. Errors may still occur, as with any automated system. Always consult the linked primary sources. Read our AI Editorial Policy.