Our Approach

Serotonergic Psychedelic Mechanism

Our approach to developing novel therapeutics is inspired by decades of psychedelic research demonstrating promising results for a variety of mental health conditions. Current treatments such as serotonin reuptake inhibitors (SSRIs) are associated with limited efficacy and harmful side effects and require continuous dosing. Classic psychedelics have been shown to produce unprecedented durable efficacy in a single dose. Specifically, RCT studies demonstrate the benefits of psilocybin in depression after one dose. Our focus is to advance the initial discoveries of 5HT2A compounds and develop new agents with safe, effective profiles.

We are advancing our lead candidate, RE104, a potential best-in-class, short duration, patented prodrug of 4-OH-DiPT, a psilocybin-like compound. RE104 targets the serotonin 2A receptor (5HT2AR), which is the recognized target for the antidepressant effects of psychedelic compounds.

With our exclusive rights to RE104, we can evaluate RE104 in various underserved mental health disorders and are actively investigating its use in additional indications susceptible to being treated with a 5HT2A agonist molecule.

INDICATIONS

Postpartum Depression

In August, Reunion announced positive topline results from the RECONNECT Phase 2 clinical trial in postpartum depression (PPD). The study met its primary endpoint, demonstrating a statistically significant and clinically meaningful reduction from baseline in the Montgomery-Åsberg Depression Rating Scale (MADRS), a key measure of depressive symptoms, as well as a robust safety tolerability profile. Additionally, data from RECONNECT suggest that patients reach discharge readiness rapidly, within four hours of treatment, consistent with RE104’s differentiated pharmacology.

Also in August, Reunion announced preliminary data from a Phase 1 clinical lactation study, which suggest that mothers may be able to return to breastfeeding rapidly following RE104 treatment. Based on these data, Reunion plans to advance RE104 into a pivotal Phase 3 clinical trial for the treatment of PPD in 2026.

PPD is a major form of depression that is estimated to affect about 15% of new mothers within the first year of giving birth, with nearly 500,000 women in the U.S. diagnosed annually. Women suffering from PPD often experience significant changes in mood, appetite and sleep contributing to feelings of hopelessness, lack of concentration, loss of energy, poor self-esteem and maternal disinterest.

The only viable regulatory approved therapy indicated for PPD has side effects that include sedation (with Black Box warning) and potential addiction and embryo-fetal toxicity. SSRIs, which are often prescribed off-label, take a long time for onset and only show limited efficacy, representing a concern for the safety, well-being and long-term development of the child.

While there have been recent developments in treatment options for PPD, there continues to be a significant unmet need for a solution that offers a faster onset of action, greater efficacy after only a single dose, with limited interruption in breast feeding and a faster return to normal daily activities.

Adjustment Disorder

Reunion is also planning to evaluate RE104 in the REKINDLE Phase 2 clinical trial as a potential treatment for adjustment disorder (AjD) in cancer and other medical illnesses. Reunion expects to initiate the REKINDLE Phase 2 trial in the third quarter of 2025.

AjD is a mental health condition defined as a disproportionate reaction to a stressful life event or change, which impacts the ability to function and is characterized by depression, anxiety and/or other behavioral and mood disturbances. Serious medical illnesses are known to be a key precipitant of AjD; it is estimated that approximately 500,000 people in the United States are diagnosed with AjD each year following a medical or health-related stressor, including 6-35% of cancer patients. A global survey of psychiatrists by the World Health Organization revealed that adjustment disorders play an enormous role in healthcare utilization; ranked 7th among 44 psychiatric categories they managed at least once a week in their practice.

Depressive and anxiety symptoms in medically ill patients with AjD can be associated with poorer medical outcomes, treatment compliance and quality of life as well as increased health care utilization. Current treatments for AjD are not consistently effective, and there are no therapies presently approved by the U.S. Food and Drug Administration (FDA) for its treatment.

AjD in cancer patients is one of the initial indications studied by researchers on psychedelic treatment and several clinical trials indicate the potential for rapid and meaningful improvements in depression and anxiety with durable changes in attitude and behavior.

Reunion believes there is a significant unmet need for a rapid acting solution for these medically ill patients to positively impact treatment compliance, hospitalization time and improved quality of life.

RE104

Reunion’s lead product candidate, RE104, is a proprietary, potential best-in-class, patented prodrug of 4-OH-DiPT designed to deliver a short psychedelic experience compared to longer experience duration psychedelics like psilocybin or LSD.

In the RECONNECT Phase 2 clinical trial in adult female patients with moderate-to-severe PPD, RE104 demonstrated a robust decrease in depression symptoms and was generally well-tolerated, consistent with previously reported Phase 1 safety data with RE104 and other psychedelic agents. Additionally, patients in RECONNECT reached discharge readiness rapidly, consistent with RE104’s differentiated pharmacology. Reunion expects to initiate a pivotal Phase 3 clinical trial of RE104 in PPD patients in 2026, following alignment with the U.S. Food and Drug Administration (FDA) on its future development pathway to a New Drug Application (NDA) for regulatory approval in the United States.

In tandem with announcing topline results from RECONNECT, Reunion also shared preliminary data from its Phase 1 clinical lactation study, an open-label, single dose study evaluating the concentration of RE104 and its major metabolites in breast milk and plasma of healthy lactating women. While final data from the study will be reviewed by the FDA, preliminary results from the study suggest that mothers who wish to return to breastfeeding following RE104 treatment may be able to do so with limited interruption.

Reunion also plans on evaluating RE104 in the REKINDLE Phase 2 clinical trial, a randomized, double-blind, parallel-group, dose-controlled study in AjD in cancer and other medical illnesses. Initiation of the study is expected in the third quarter of 2025.

RE245

RE245 is a discovery-stage, non-psychedelic asset, for application in chronic treatment paradigms and indications. RE245 is structurally similar to classic psychedelics and is designed as an orally-bioavailable 5HT2A agonist, which provides therapeutic mental health benefits for chronic conditions without causing hallucinations or cardiotoxicity.