MPM BioImpact-owned Reunion raises $103M, one of the largest rounds for a psychedelic biotech

It’s taken decades for psychedelics to regain clinical and regulatory relevance. But, in just a matter of months, progress has accelerated, with a biotech raising one of the largest private rounds ever for the field.

Reunion Neuroscience has cashed in on a $103 million series A, building on the promise of a phase 2-stage psychedelic prodrug being developed as a treatment for postpartum depression. The round was led by two major biotech investors: MPM BioImpact—which acquired Reunion in August 2023—and Novo Holdings.

Reunion’s lead asset, RE104, is a prodrug of 4-OH-DIPT, replicating the effects of the magic mushroom extract psilocybin in about half the time. The company says the average effect time in a phase 1 study was less than four hours, compared to 6-8 hours for patients treated in Compass Pathways’ psilocybin study. The reduced administration time has become a central attribute that institutional investors have said they’re looking for to make bets on the modality.

“I think the entire psychedelic sector is benefiting from the Spravato experience,” Reunion CEO Greg Mayes said in an interview with Fierce Biotech. Spravato is Johnson & Johnson’s intranasal S-ketamine therapy approved as an adjunctive treatment for patients with treatment-resistant depression. Healthcare professionals are asked to monitor patients for at least two hours after administration.

Novo Holdings Managing Partner and Head of Venture Investments Scott Beardsley told Fierce in March that the firm, which is Novo Nordisk's largest shareholder, was looking at “several” potential psychedelic-based investments and could choose one or two in the coming year.

“It's a growing field,” Beardsley said at the time. “So there's a lot of discovery going on now.” 

Mayes said the fresh capital would help Reunion fund the phase 2 trial just getting underway, with data expected in the second quarter of 2025. The biotech will also explore RE104 as a treatment for adjustment disorder in patients diagnosed with cancer, one of the most well-documented uses of psychedelics in academic research to date. 

Research published in 2016 by the late neuroscientist and esteemed psychedelic researcher Roland Griffiths, Ph.D., found that a high dose of psilocybin significantly improved the well-being of patients given a life-threatening cancer diagnosis. 

“We'll be the first company to take that bolus of data in cancer patients but with a specific pathway through an adjustment disorder indication,” Mayes said. Reunion will also continue working on RE200, which targets the serotonin 2A receptor. 

Reunion’s raise is one of the largest among psychedelic drug developers or adjacent competitors. Lykos Therapeutics closed a $100 million series A earlier this year, and Delix Therapeutics brought in $70 million in September 2021. But, maybe more indicative of psychedelics' rise than the capital itself, was the focus of investors during the fundraising process, particularly, Mayes noted, since the company has yet to dose a patient in phase 2 study. 

“A lot of time and energy was spent on commercial distribution, patient access and administration issues,” he said, affirming his confidence that Reunion is up to the task.