Recursion Doses First Patient in Phase 1 Trial of AI-Designed MALT1 Inhibitor

Recursion has dosed the first patient in its Phase 1 EXCELERIZE trial of REC-3565, a selective MALT1 inhibitor targeting relapsed or refractory B-cell lymphomas. The compound was developed in 15 months using Recursion’s AI-enabled platform, which integrates physics-based modeling, molecular dynamics, and hotspot analysis.

MALT1 is part of a signaling pathway that helps immune cells grow and survive. In certain blood cancers, this pathway becomes overactive, driving tumor progression. By selectively blocking MALT1’s enzymatic activity, REC-3565 aims to disrupt this growth signal. Its design also avoids interfering with UGT1A1, a liver enzyme commonly affected by other MALT1 inhibitors—reducing the risk of hyperbilirubinemia and enabling safer dose escalation.

The compound demonstrated durable tumor regressions in preclinical models, including when paired with BTK inhibitors. The ongoing open-label, multicenter trial will evaluate safety, pharmacokinetics, pharmacodynamics, and preliminary efficacy. Part A is focused on monotherapy dose escalation; Part B will assess combination regimens to inform future studies.

In January this year, Recursion announced REC-3565’s planned advancement to the clinic alongside REC-4539, a reversible, brain-penetrant LSD1 inhibitor for small-cell lung cancer (SCLC). Both assets emerged from Recursion OS, a platform combining multimodal experimental data with causal AI to guide drug design and patient selection. Following its merger with Exscientia in late 2024, Recursion’s pipeline now includes over 10 clinical and preclinical programs supported by a 60-petabyte proprietary dataset.

Topics: Clinical Trials