Axsome's SUSTAIN Readout Slips to 2027 as Sunosi Franchise Awaits Successor Data
The Phase 3 shift work disorder trial for solriamfetol has no posted results and a 2026 guidance date already missed, with the AppliedXL model's 98.5% endpoint-met read resting on trial-design features rather than any disclosed efficacy signal.
Executive Summary
- Axsome's own disclosures moved SUSTAIN topline guidance from 2026, stated in filings from November 2024 through August 2025, to 2027 in disclosures from February and May 2026, a full-year push with no new clinical data attached to the change Press ReleasePress ReleaseFeb 23, 2026.
- NCT06568367 has posted no results on ClinicalTrials.gov and the trial remains recruiting toward a December 1, 2026 primary completion date, meaning the probability of success figures below describe a model's structural read, not an observed outcome NCT06568367Studying Solriamfetol Modulation of TAAR-1, Dopamine, and Norepinephrine in Shift Work Disorder (SUSTAIN)NCT06568367.
- The 98.5% endpoint-met read leans on enrollment-per-arm and phase-level historical base rates rather than any solriamfetol-specific efficacy signal, and the model itself flags LOW confidence on this figure [AXL-MODEL].
- Solriamfetol, marketed as Sunosi, generated $124.8 million in 2025 net product revenue, up 32% year over year, giving a positive SUSTAIN result a defined commercial pathway into shift work disorder Press ReleasePress ReleaseFeb 23, 2026.
- Until SUSTAIN reports, the readthrough case rests on protocol stability and Sunosi's existing revenue base rather than on any disclosed efficacy or safety evidence from this specific trial.
The guidance shift
Axsome Therapeutics disclosed in its February 2026 fourth-quarter results and again in May 2026 that topline results from the Phase 3 SUSTAIN trial (NCT06568367) are now anticipated in 2027 Press ReleasePress ReleaseFeb 23, 2026. That represents a change from the company's prior guidance: filings from November 2024, May 2025, and August 2025 had each pointed to a 2026 readout for the same trial Press ReleasePress ReleaseFeb 23, 2026. Chief Executive Herriot Tabuteau framed 2026 broadly as a year of "continued commercial execution, and multiple regulatory and clinical milestones" for the company's pipeline, without singling out a firm SUSTAIN date Press ReleasePress ReleaseFeb 23, 2026.
Probability of SuccessBased on the AppliedXL Probability of Success model. For more information about the methodology, read the research here.
What the trial measures
SUSTAIN is a randomized, placebo-controlled, three-arm study enrolling 520 adults with shift work disorder across United States and Canada sites NCT06568367Studying Solriamfetol Modulation of TAAR-1, Dopamine, and Norepinephrine in Shift Work Disorder (SUSTAIN)NCT06568367. It carries two co-primary endpoints: change from baseline to Week 12 in the Clinical Global Impressions of Severity of Illness for night-shift sleepiness, and change from baseline to Week 12 in mean sleep latency measured by the Maintenance of Wakefulness Test NCT06568367Studying Solriamfetol Modulation of TAAR-1, Dopamine, and Norepinephrine in Shift Work Disorder (SUSTAIN)NCT06568367. No efficacy, safety, or effect-size data for either endpoint has been disclosed, and ClinicalTrials.gov shows no posted results for the study.
Operational signals
The trial's protocol has recorded zero eligibility, endpoint, or primary-completion-date changes since it was first posted on August 23, 2024, a stability label the tool assigns as "Stable". The primary completion date has held at December 1, 2026 NCT06568367Studying Solriamfetol Modulation of TAAR-1, Dopamine, and Norepinephrine in Shift Work Disorder (SUSTAIN)NCT06568367. That consistency argues against enrollment trouble as the driver of the guidance slip, though the dossier does not disclose the specific reason topline timing moved from 2026 to 2027.
Commercial and competitive stakes
Solriamfetol is already approved and marketed as Sunosi, which generated $124.8 million in net product revenue in 2025, up 32% year over year, behind only AUVELITY among Axsome's marketed products Press ReleasePress ReleaseFeb 23, 2026. A positive SUSTAIN result would extend Sunosi into a third indication alongside narcolepsy and obstructive sleep apnea. Landscape data show SUSTAIN is the only active trial pairing the TAAR-1 target with shift work disorder, so there is no direct competitor readout to benchmark against; the nearest comparable indication trial, Novartis's LML134 program (NCT03141086), used a different, unspecified mechanism and stopped at Phase 2.
Reading the model number
The AppliedXL model puts endpoint-met probability at 98.5%, but flags that read as LOW confidence with a wide uncertainty band [AXL-MODEL]. The dominant drivers are enrollment-per-arm and historical endpoint-type success rates at Phase 3, structural features tied to trial design and base rates rather than any solriamfetol-specific clinical signal [AXL-MODEL]. Separately, the model's clinical-significance score sits at 49.6%, near a coin flip, indicating the model itself does not treat a statistical win here as assured to be clinically meaningful [AXL-MODEL].
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.