Sunstone Therapies Announces Publication of Positive Phase 2 Study Results in Cancer

Phase 2 trial demonstrated the safety and efficacy of psilocybin-assisted group therapy for treatment of major depressive disorder in patients with cancer

Group setting and 1:1 patient-to-therapist ratio has potential to increase accessibility of psilocybin-assisted therapy

Further publication gives insight into patient experience

Sunstone Therapies, a leader in the delivery of psychedelic-assisted therapy in the medical setting and the development and execution of clinical trials, announces the publication in Cancer of the full results and methodology for its phase 2 clinical trial assessing the safety, tolerability, feasibility, and preliminary efficacy of psilocybin-assisted therapy to treat cancer patients suffering from major depressive disorder.

This phase 2, open-label trial administered psilocybin to cohorts of 3-4 participants with curable and incurable cancer and major depressive disorder, with individual and group therapeutic support before, during, and after dosing. Topline results were published in JAMA Oncology in April 2023.

Thirty participants completed the study, with results indicating that psilocybin-assisted therapy in group cohort administration was safe, feasible, and effective. Cohorts of 3-4 patients were simultaneously treated with a single 25mg dose of synthesized COMP360 psilocybin in adjacent rooms open at the same time, in a 1:1 therapist-to-patient ratio. The cohorts had preparation prior, and integration following the therapy as a group. Previous studies have always maintained a 2:1 therapist-to-patient ratio through all parts of the therapy. These results showed that the group approach is feasible and many patients believed it to be of additional benefit.

Psilocybin-assisted therapy was shown to induce a clinically meaningful reduction in depression severity (MADRS) scores by 19.1 points (95% CI 22.3 to -16.0, p<0.0001) from baseline to post-treatment of Week 8 following administration. Eighty percent of participants demonstrated a sustained response to psilocybin treatment; 50% showed full remission of depressive symptoms at Week 1, which was sustained for eight weeks. The study found no incidence of psilocybin-related serious adverse events, no reported suicidality, and treatment-related adverse events (e.g., nausea, headache) as generally mild and expected.

A second study published in Cancer led by Yvan Beaussant, MD, MSc, of Dana-Farber Cancer Institute, gathered information from patients in the trial using exit interviews. Participants’ experiences were generally positive and they felt being part of a group helped from a safety perspective, increasing their sense of preparedness and managing fear. In terms of efficacy, patients felt being connected to the group deepened and enriched their experience. The use of both individual and group sessions was also described as supportive of the therapy.


“This was a pioneering study which added to the growing body of evidence for the effectiveness of psilocybin-assisted therapy in tackling the mental distress experienced by patients with cancer and also, importantly, demonstrated the feasibility of a group and 1:1 patient-to-therapist ratio. Efficient, scalable delivery while maintaining safety is a key issue for psilocybin-assisted therapy and the results of this study suggest a pathway towards wider and faster adoption in the future.”

-Manish Agrawal MD, Chief Executive Officer and Co-founder, Sunstone Therapies, and Principal Investigator on the study


About Sunstone Therapies

Sunstone Therapies is a leader in the delivery of psychedelic-assisted therapy in the medical setting, focusing on clinical trials today and future clinical delivery when therapies are approved. Sunstone is establishing the gold standard for psychedelic clinics in order to deliver care that reduces the emotional suffering of those affected by cancer and complex mental health challenges and disorders, and to make safe, effective psychedelic-assisted therapy accessible.