Arsenal Biosciences cuts 99 jobs as it pivots to in-vivo CAR-T therapy

Arsenal Biosciences announced a major restructuring, laying off 99 employees, which represents the majority of its workforce across all teams and locations.

The company is ending development of its ex vivo clinical assets and shifting its research to in-vivo CAR-T therapy, leveraging its foundational knowledge of T-cell biology.

This layoff follows a previous reduction in September 2025 that left the firm with 127 staff, meaning the latest cuts dramatically shrink the company.

ArsenalBio had raised $325 million two years ago with backing from Bristol Myers Squibb and Regeneron, and a partnership with Roche's Genentech, and now seeks new homes for its assets.

CEO Ken Drazan said the decision was not made lightly but is intended to advance the field and help patients.