Recursion Reports Encouraging Interim Phase 1 Data a Selective CDK7 Inhibitor
Recursion (Nasdaq: RXRX) announced interim findings from the ongoing Phase 1/2 ELUCIDATE trial evaluating REC-617, a precision-designed, oral CDK7 inhibitor developed to address common resistance pathways in advanced solid tumors. The trial’s early results highlight a confirmed partial response in a heavily pre-treated patient and an overall favorable safety profile across multiple dose levels.
Although efficacy was not a primary endpoint in this early phase—nor typically expected at this stage—Recursion views the observed patient stability and response as promising given the heavily pre-treated population and preliminary nature of the data.
David Hallett, Ph.D., Chief Scientific Officer, Recursion:
“Cell cycle dysregulation and transcriptional ‘addiction’ are both hallmarks of many aggressive cancers. By inhibiting CDK7, we have the potential to target both mechanisms while fine tuning the therapeutic index. Using our precision design platform, we created a molecule with rapid oral absorption to reduce GI tissue exposure, a suitable half life to manage side effects, and target engagement covering the IC80 level.”
Najat Khan, Ph.D., Chief R&D Officer and Chief Commercial Officer, Recursion:
“These initial findings for REC-617 represent an exciting step forward in the development of CDK7 inhibitors, with a favorable PK/PD profile and a durable confirmed partial response observed in dose escalation in a highly pre-treated patient population. Designed using our AI-powered OS platform, REC-617 reflects our focus on enhancing the therapeutic index to deliver more effective and safer treatment options for patients. We are eager to continue this momentum in dose escalation and to initiate the next phase of the program next year.”
Clinical Efficacy and Safety Highlights
- A confirmed partial response (PR) by RECIST in a patient with platinum-resistant ovarian cancer who had received four prior lines of therapy; the response is ongoing after more than six months.
- Four additional patients achieved stable disease (SD) for up to six months.
- REC-617 showed a generally favorable safety profile with mostly Grade 1-2, on-target, reversible adverse events. No maximum tolerated dose (MTD) has been reached, and no discontinuations due to adverse events were reported.
REC-617 demonstrated dose-linear pharmacokinetics with rapid absorption and a half-life of approximately 5-6 hours. Early POLR2A modulation indicates around 80–90% target engagement, and twice-daily dosing is under investigation to potentially optimize clinical benefit.
Recursion plans to continue monotherapy dose escalation and initiate combination therapy studies in the first half of 2025. Additional data from ELUCIDATE and preclinical studies of REC-617 will be shared at future medical meetings.
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About ELUCIDATE
ELUCIDATE is a Phase 1/2, multicenter, open-label study evaluating REC-617 (GT Apeiron's, then Exscientia's GTAEXS617, prior to the Recursion-Exscientia merger in August 2024) as both a monotherapy and in combination with other treatments. The trial’s primary goals include assessing safety, pharmacokinetics, pharmacodynamics, and efficacy in advanced solid tumors, including NSCLC, colorectal cancer, breast cancer, pancreatic cancer, ovarian cancer, and head and neck cancer. Dose escalation in both monotherapy and combination settings aims to determine the optimal biological dose (OBD) before proceeding to the expansion phase.
