Reunion's Psychedelic Prodrug Shows Promise in Postpartum Depression Phase 2 Trial

Reunion Neuroscience, a biotech company recently acquired by MPM BioImpact, has announced positive results from a phase 2 study of its novel psychedelic prodrug, RE104, for the treatment of postpartum depression (PPD). The trial's success paves the way for late-stage clinical development and highlights the growing potential of psychedelic-based therapies in addressing mental health disorders.

Impressive Efficacy in Reducing PPD Symptoms

The phase 2 study, which enrolled 84 adult female patients with moderate to severe PPD, demonstrated significant improvements in depression scores. A single 30-mg subcutaneous dose of RE104 led to a 50% or greater improvement in depression scores for 77.1% of patients at Day 7, compared to 61.6% in the active control group receiving a 1.5 mg dose.

Notably, the 30-mg cohort experienced an average reduction of 23 points in the Montgomery-Åsberg Depression Rating Scale (MADRS) score from baseline, surpassing the 17.2-point reduction observed in the control arm. Furthermore, 71.4% of patients in the RE104 arm achieved remission (MADRS score ≤10) by Day 7, compared to 41% in the control group.

Dr. Mark Pollack, Reunion's Chief Medical Officer, expressed optimism about the results, stating, "We are encouraged by the results from our Reconnect phase 2 trial, which provide strong clinical validation for RE104 as a well-tolerated and effective treatment for PPD offering rapid relief with minimal interruption to daily activities."

Safety Profile and Practical Considerations

RE104 demonstrated a favorable safety and tolerability profile, with mild to moderate side effects primarily occurring on the treatment day. The most common adverse events were nausea (44% of patients) and headache (34% of patients), which generally resolved spontaneously.

A key advantage of RE104 is its shorter duration of action compared to other psychedelic compounds. The study reported that 92.7% of patients were ready for discharge within four hours of treatment, potentially offering a more practical option for new mothers. Additionally, preliminary data from a lactation study suggested that mothers could quickly resume breastfeeding after treatment.

Future Developments and Expansion

Building on these promising results, Reunion Neuroscience plans to advance RE104 into a pivotal phase 3 trial for PPD in 2026. The company is also expanding its clinical program to explore RE104's potential in other mental health indications:

1. A phase 2 study for adjustment disorder (AjD) in patients with cancer and other illnesses is set to launch in the coming weeks.
2. Another phase 2 trial targeting an undisclosed "significant mental health indication" is scheduled for the first quarter of 2026.

These developments are supported by a substantial $103 million Series A funding round completed in May 2024, which attracted notable investors such as Novo Holdings. The investment reflects growing confidence in the potential of psychedelic-based therapies to address unmet needs in mental health treatment.

As the psychedelic therapy landscape continues to evolve, RE104's progress adds to the momentum generated by other compounds in the field, such as Compass Pathways' COMP360 psilocybin therapy, which recently showed positive results in a phase 3 trial for treatment-resistant depression. With its promising efficacy and practical advantages, RE104 may indeed contribute to redefining the standard of care for PPD and other mental health conditions.