Cybin Inc's stock rose 8.2% on Tuesday after the company disclosed positive Phase 2a results for SPL026, an investigational short-acting serotonergic agonist aimed at treating major depressive disorder (MDD). The data come from a randomized, placebo-controlled trial that achieved its primary endpoint.
The study showed that participants who received a single 21.5 mg dose of SPL026 registered a mean improvement versus placebo of -7.35 points on the Montgomery-Åsberg Depression Rating Scale (MADRS) at two weeks. Antidepressant effects were observed as early as one week after treatment and, for many participants, were durable - maintained for up to three months and, in some cases, extending as long as six months.
At Week 2, response rates were 35% in the SPL026 group compared with 12% in the placebo group, while remission rates were 29% versus 12%, respectively. The treatment was generally well tolerated across participants and no treatment-related serious adverse events were reported. The trial results were published in Nature Medicine.
Commenting on the findings, Dr. David Erritzoe, lead investigator of the trial from Imperial's Department of Brain Sciences, said: "We have shown that a single dose of SPL026 is safe, effective and durable, with treatment effects comparable to other promising interventional treatments often requiring much longer treatment sessions."
Although Cybin's parent company, Helus Pharma, is not advancing intravenous SPL026 in its present form, the company says the findings will inform development of its HLP004 program. Helus is advancing HLP004 - described as a proprietary novel serotonergic agonist targeted at generalized anxiety disorder (GAD) - and expects to report Phase 2 topline data in the first quarter of 2026.
Market context and implications
The clinical readout and accompanying publication appear to have influenced investor sentiment in Cybin's shares, reflected in the intra-session stock move. The data establish clinical signals of efficacy, durability and tolerability for a single-dose intervention in MDD within the parameters reported by the trial.
Further development decisions by Helus will determine whether and how the SPL026 findings translate into additional clinical programs or product strategies, including the ongoing HLP004 development for GAD.