Aleta Biotherapeutics

Aleta Biotherapeutics is a Natick, Massachusetts immuno-oncology company building CAR T Engagers (CTEs) - simple biologic proteins that make existing CAR-T cell therapies work better. Its lead drug, ALETA-001, bridges a patient's CD19-targeted CAR T-cells to CD20 on cancer cells, aiming to rescue patients who relapse after standard CAR-T treatment for B-cell cancers. Founded in 2015 by Paul Rennert and Roy Lobb, the company is running a Phase 1/2 trial in the UK with Cancer Research UK and reported encouraging early data in December 2025.