Compass Pathways' delayed phase 3 readout for its psilocybin treatment has hit its primary endpoint of reducing the severity of patients’ depression, but investors appear unimpressed.
The study evaluated COMP360, a synthetic form of the magic mushroom extract psilocybin, in 258 patients with treatment-resistant depression (TRD). The trial hit its main goal by demonstrating that a single 25-mg dose of COMP360 reduced the severity of depression symptoms by 3.6 points on the Montgomery-Åsberg Depression Rating Scale (MADRS) score at Week 6 when compared to placebo.
Despite Compass celebrating the readout as both “highly statistically significant” and “clinically meaningful,” investors appeared unimpressed with the results—sending Compass’ stock down 36% to $2.96 in premarket trading Monday from a Friday closing price of $4.63.
The safety data were consistent with previous studies of COMP360, Compass pointed out, with “no evidence of a clinically meaningful imbalance between treatment arms in suicidality in either study.”
Compass is planning to share 26-week data from the COMP005 study once all patients have completed the initial six-week portion of another study dubbed COMP006. That trial is evaluating doses of 1 mg, 10 mg and 25 mg.
“The positive topline results at week 6 from the COMP005 trial underscore the innovative potential of psilocybin treatment in mental health care for which Compass Pathways continues to pave the way,” CEO Kabir Nath said in the release.
“We eagerly anticipate further insights once we have the full dataset, and also look forward to findings from COMP006, which will explore the efficacy of two fixed doses,” Nath added. “We remain focused on our goal of transforming the landscape of mental health treatment.”
Compass said it plans to discuss these “preliminary COMP005 data” with the FDA, which “has not yet reviewed” the findings.
“As we continue our phase 3 program, we are very encouraged by the initial positive results and the highly statistically significant and clinically meaningful change in the MADRS score between the arms of the study 6 weeks after a single administration of COMP360,” Compass Chief Medical Officer Guy Goodwin, M.D., said in the June 23 release.
“This progress marks an important milestone for patients living with TRD and highlights the groundbreaking work Compass Pathways is doing to bring innovative treatments to those who have been failed by multiple currently approved available treatment options,” Goodwin added.
Today’s readout has been a while coming, with Compass announcing last October that the depression data would be delayed beyond the original deadline of summer 2024. At the time, Nath blamed “a number of items related to the complexity of the trials that we're now learning along the way.”
Compass used the same announcement to push back the COMP006 readout until next year, although it framed that delay in the context of the FDA’s rejection of Lykos Therapeutics’ MDMA therapy, including “a high degree of scrutiny regarding unblinding, which is very relevant to our studies.”
Those delays were paired with Compass shrinking its head count by 30% and halting all preclinical work unrelated to COMP360.