AtaiBeckley Inc. (ATAI) has reported new Phase 2a data showing that a single intranasal dose of its investigational therapy BPL-003 produced a rapid and durable antidepressant response in adults with treatment-resistant depression who remained on stable SSRI therapy.
Treatment-resistant depression affects roughly 30% of people living with major depressive disorder and is defined as failing to respond to at least two prior antidepressants. For many patients, symptoms persist for years, and available treatments often require multiple doses, long clinic visits, or have delayed onset.
In the open-label Phase 2a study, published in CNS Drugs, 66.7% of participants (8 out of 12) achieved an antidepressant response-defined as at least a 50% reduction in MADRS score- by Day 2 after receiving a single intranasal dose of BPL-003. Both the 10 mg and 12 mg dose groups showed the same Day-2 response rate. The effect was also durable, with 83% of participants in the 10 mg cohort and 66.7% in the 12 mg cohort maintaining a response at Week 12.
BPL-003, a proprietary intranasal formulation of mebufotenin benzoate (5-MeO-DMT), is designed to deliver rapid antidepressant effects with a short treatment experience of about two hours. The therapy received FDA Breakthrough Therapy Designation in October 2025.
According to the company, BPL-003 was generally well tolerated, with no serious adverse events reported. Participants were typically ready for discharge about 100 minutes after dosing, supporting the potential for use in outpatient interventional psychiatry settings.
The study represents Part 2 of a four-part Phase 2a program. Part 1, evaluating BPL-003 as monotherapy, showed similarly rapid and sustained reductions in depression scores. Part 3 topline data, announced earlier, suggested that a second dose at Week 2 may provide additional benefit without compromising safety. Part 4, which is evaluating a two-dose induction regimen in patients receiving defined antidepressants, is ongoing with initial data expected in Q4 2026.
AtaiBeckley's CEO, Srinivas Rao, said the results reinforce the potential of BPL-003 to "transform the treatment paradigm" for TRD as the company prepares to begin Phase 3 trials in Q2 2026. Chief Medical Officer Kevin Craig added that the ability to administer BPL-003 alongside SSRIs without reducing efficacy is an important advancement, given that many TRD patients remain on chronic SSRI therapy.
BPL-003 is part of AtaiBeckley's broader pipeline of rapid-acting mental health treatments, which also includes VLS-01 for TRD and EMP-01 for social anxiety disorder.
ATAI has traded between $1.15 and $6.75 over the past year. The stock closed Tuesday's trading at $3.79, down 1.56%. In pre-market trading the stock is at $4.10, up 8.18%.
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