Shares of Atai Life Sciences (Nasdaq: ATAI) plunged by more than 40% after phase 2a clinical trial results looking at ketamine therapy to treat depression failed to meet its primary endpoint.
Atai said that while findings showed “signals of efficacy across all timepoints out to two weeks,” the treatment did not prove enough of a statistically significant change in participants’ baseline depression score after 24 hours versus the placebo.
“We thank all the patients, families, caregivers, and investigators for their support and participation in the PCN-101 Phase 2a trial,” Atai’s CEO and co-founder Florian Brand said in a statement.
The company said it will continue to evaluate the PCN-101 data in more detail over the next weeks and will work with its subsidiary Perception Neuroscience to explore next steps, “including but not limited to seeking strategic partnership options.”
Atai, which had a decent 2022 amid sizable losses and negative cash flows, has fared better than most despite accumulating a deficit since 2018 of $465 million as of September 2022.
On an investors call last November, Brand said that the study had been about testing “whether we have a greater therapeutic index compared to other approved treatment options.”
Without getting into details at the time, he said, “Regarding specific thresholds, efficacy of a single dose below what is considered clinically meaningful would certainly lead to us reassessing the current clinical development plan in treatment-resistant depression.”
The phase 2a proof-of-concept trial was a two-week, randomized, double-blind, placebo-controlled multi-center study assessing the safety, tolerability and efficacy of a single IV administration of PCN-101.
102 patients with treatment-resistant depression were enrolled across three arms – 30 milligrams, 60 milligrams, and placebo. The patients had previously failed at least two rounds of antidepressants. They received a single IV dose of PCN-101 alongside their existing treatment regimen.
Patients’ depression scores were measured using the Montgomery-Åsberg Depression Rating Scale (MADRS) at intervals over two weeks, with the primary endpoint at 24 hours post-dose. Dissociation and sedation were measured using the Clinician-Administered Dissociative States Scale (CADSS) and the Modified Observer’s Alertness/Sedation Scale (MOAA/S), respectively.
On the primary endpoint of MADRS at 24 hours, the mean change from baseline was -15.3 for PCN-101 60 mg compared to -13.7 for placebo (-1.6 pbo-adj; p-value 0.5). The single 60 mg dose of PCN-101 showed an efficacy signal at each timepoint over the 2-week timeframe of the study.
Key secondary endpoints included a proportion of patients who experienced 50% improvement from baseline in MADRS, and a proportion of patients in remission. Despite seeing greater response and remission rates in the 60 mg arm, the trial did not meet statistical significance at any timepoint on these secondary measures.
Atai said that PCN-101 was generally well-tolerated with rates of sedation and dissociation comparable to placebo, and claims it demonstrated an “encouraging safety profile and signals of efficacy across all timepoints,” despite not achieving statistical significance on the primary endpoint.