Recursion Announces Completion of Phase 1 Study for REC-3964 for Clostridioides Difficile Infection


Recursion recently announced it has completed the Phase 1 study for REC-3964 in healthy volunteers. The study achieved its primary objectives of assessing the safety, tolerability, and pharmacokinetic profile of REC-3964. REC-3964 has been well tolerated with no serious adverse events (SAEs) reported.

“This is an important step in our efforts to rapidly translate our first new chemical entity into a safe and effective therapy that has the potential to address a significant unmet need,” said David Mauro, MD, PhD, Chief Medical Officer of Recursion. “We are encouraged by the strong safety and tolerability profile and are actively exploring the most expeditious path to advance this program to patients.”

REC-3964 is a novel non-antibiotic small molecule inhibitor of C. difficile toxins that is being developed for the potential treatment of Clostridioides difficile (C. diff) infection, a bacterial disease that impacts more than 730,000 people in the US and EU5 every year. REC-3964 is Recursion’s first and most advanced new chemical entity, demonstrating the power of Recursion’s platform to rapidly identify, validate, optimize and translate novel insights into clinical candidates.

REC-3964 represents a novel small molecule approach designed to selectively inhibit the toxin produced by Clostridioides difficile in the gastrointestinal tract. This molecule has the potential, when used as part of a treatment regimen, to prevent recurrent disease and/or other forms of C. diff infection, which is a leading cause of antibiotic-induced diarrhea sometimes leading to significant morbidity and mortality. More than 29,000 patients die in the US every year from C. diff infection.

The Phase 1 study was designed as a first-in-human protocol evaluating single and multiple doses of orally administered REC-3964 in healthy volunteers. The study assessed the safety, tolerability and pharmacokinetic (PK) profile of REC-3964 and consisted of two parts: single ascending dose (SAD) and multiple ascending dose (MAD). Dosing levels for MAD were 100 mg (Cohort 1), 300 mg (Cohort 2), 500 mg (Cohort 3), and 900 mg (Cohort 4). In Cohort 1, 12 participants were randomized to receive either REC-3964 (N=10) or placebo (N=2) and in each Cohorts 2 through 4, 10 participants were randomized to receive either REC-3964 (N=8) or placebo (N=2) for a total of 42 participants for the MAD study. Participants were dosed with REC-3964 for 14 days.

PK analysis demonstrated that exposures (AUC) increased approximately dose-proportionally across the dose ranges tested and the half-life ranged from approximately 7 to 10 hours. As a result, twice-daily (BID) dosing is expected to reach targeted trough concentrations. Overall, REC-3964 was very well tolerated. Four participants (11.8%, N=34) experienced treatment-related adverse events, which were mild. Additionally, no treatment-related SAEs were observed, and there were no discontinuations due to a treatment-related adverse event. Based on these data, a Phase 2 proof-of-concept trial is expected to initiate in 2024 to further study the attributes of this molecule.

Recursion (NASDAQ: RXRX) is a clinical-stage TechBio company leading the space by decoding biology to industrialize drug discovery. Enabling its mission is the Recursion OS, a platform built across diverse technologies that continuously expands one of the world’s largest proprietary biological and chemical datasets. Recursion leverages sophisticated machine-learning algorithms to distill from its dataset a collection of trillions of searchable relationships across biology and chemistry unconstrained by human bias. By commanding massive experimental scale — up to millions of wet lab experiments weekly — and massive computational scale — owning and operating one of the most powerful supercomputers in the world, Recursion is uniting technology, biology, and chemistry to advance the future of medicine. Recursion is headquartered in Salt Lake City, where it is a founding member of BioHive, the Utah life sciences industry collective. Recursion also has offices in Toronto, Montréal, and the San Francisco Bay Area. For more information, visit www.Recursion.com.