Compass Pathways Publishes Positive Phase 2 Data for COMP360 in PTSD

Publication of COMP360 Phase 2 Results for PTSD

Compass Pathways plc (Nasdaq: CMPS) today announced the formal publication of positive results from its open-label Phase 2 study evaluating COMP360 synthetic psilocybin for the treatment of post-traumatic stress disorder (PTSD). The findings, initially disclosed in May 2024, have now been detailed in the Journal of Psychopharmacology, providing further validation for the investigational therapy.

Study Details and Efficacy Profile

The Phase 2 study involved 22 patients with PTSD who received a single 25 mg dose of COMP360. The treatment was reported as well-tolerated, with no serious adverse events observed. Common treatment-emergent adverse events included headache (50.0%), nausea (36.4%), crying (27.3%), fatigue (27.3%), and visual hallucinations (22.7%).

Crucially, the study demonstrated rapid and durable improvement in PTSD symptoms from baseline, maintained for up to 12 weeks following a single administration. High rates of response, with 81.8% of patients showing improvement at week 4, and remission, with 63.6% of patients no longer meeting PTSD diagnostic criteria at week 4, were observed. The mean CAPS-5 total score, a measure of PTSD severity, saw a 29.9-point reduction at week 4 and a 29.5-point reduction at week 12 from a baseline of 47.5. Similarly, the Sheehan Disability Scale (SDS) score, assessing functional impairment, improved by 11.7 points at week 4 and 14.4 points at week 12 from a baseline of 22.7.

Market Context and Analyst Outlook

The publication of these positive PTSD results arrives following a period of significant volatility for CMPS shares. Earlier in 2025, the stock experienced a sharp decline of nearly 50% after the announcement of its first Phase 3 trial results for COMP360 in Treatment-Resistant Depression (TRD). While that trial met its primary endpoint, the reduction in depression symptoms fell short of Wall Street's higher expectations. As of late June 2025, CMPS held a market capitalization of $248 million, with shares down 54% over the preceding 52 weeks and 27% year-to-date. However, the stock's price-to-book ratio of 1.31x presents a valuation significantly below the sector median of 2.7x.

Despite past share price movements, analyst sentiment remains largely positive, with an average "Strong Buy" rating and a 12-month stock price target of $17.0, representing a substantial 200.35% upside from recent prices. The positive PTSD data is expected to reinforce investor confidence in the company's research and development capabilities and the broader potential of its pipeline.

Addressing Unmet Medical Need and Broader Implications

PTSD affects approximately 13 million people in the U.S. alone, with Dr. Guy Goodwin, Chief Medical Officer at Compass Pathways, highlighting it as an area of profound unmet medical need with limited innovation. The successful Phase 2 data for COMP360 positions the company to potentially address this critical gap, following in the footsteps of other psychedelic-assisted therapy developments. For instance, Bionomics Limited saw its shares surge almost 400% in September 2023 on positive Phase IIb results for its PTSD treatment, illustrating the market's responsiveness to promising data in this field.

Financially, Compass Pathways reported a net loss of $38.4 million, or $0.41 per share, for Q2 2025. This marked an improvement from a $0.56 loss per share in Q2 2024 and surpassed analyst estimates of a $0.43 per share loss. The company maintains a strong cash and cash equivalents position of $221.9 million as of June 30, 2025, providing a cash runway expected to fund operations into 2027. Research and development expenses for Q2 2025 increased to $30.3 million from $29.1 million in Q2 2024, primarily driven by the advancement of its late-stage COMP360 Phase 3 clinical trials for TRD.

Strategic Direction and Future Outlook

Building on the encouraging Phase 2 results, Compass Pathways is actively finalizing late-stage clinical trial designs for COMP360 in PTSD. Concurrently, the company is exploring options for an accelerated regulatory filing for COMP360 in TRD, where it has already received FDA Breakthrough Therapy designation. The appointment of Justin Gover, former CEO of GW Pharmaceuticals, to the board of directors signals a strategic focus on commercialization and navigating complex regulatory pathways, drawing on his experience with FDA-approved cannabis-derived medicines.

The broader psychedelic-assisted mental healthcare market is undergoing a significant paradigm shift, driven by increasing scientific validation and regulatory innovation. The forthcoming FDA decision on MDMA therapy for PTSD (from Lykos Therapeutics) is a keenly watched event that could further shape the regulatory landscape and investor appetite for novel treatments in this sector. Compass Pathways is positioning itself as a leader in this evolving market, with the COMP360 PTSD program representing a key pillar of its growth strategy alongside ongoing TRD trials.