Prelude Therapeutics, Eli Lilly to Study Breast Cancer Drug Combinations in Phase 1 Trial

07:39 AM EDT, 10/13/2026 (MT Newswires) -- Prelude Therapeutics (PRLD) said Tuesday it signed a clinical trial collaboration and supply agreement with Eli Lilly (LLY) to evaluate its experimental drug, PRT13722, in combination with Lilly's breast cancer treatments abemaciclib and imlunestrant. The company said the US Food and Drug Administration recently cleared the study to proceed under its investigational new drug application, and the phase 1 trial will evaluate the drug combinations in patients with breast cancer and is expected to begin enrolling patients in Q4. The study will initially test PRT13722 alone before advancing to combination treatments, Prelude said. Preclinical studies showed that PRT13722 reduced tumor growth and was active when combined with other cancer treatments in breast cancer models, the company said. Prelude said it retains full global development and commercial rights to PRT13722, while Lilly will supply abemaciclib and imlunestrant for the study.