Prime Medicine CEO Exits Amidst Layoffs and Restructuring as Sole Clinical Gene Therapy Shelved

Prime Medicine CEO Keith Gottesdiener has stepped down as part of a major company restructuring, effective as of May 19, 2025, with CFO Allan Reine appointed as the new CEO345.

The company is laying off approximately 25% of its workforce—about 50 employees15.

Prime Medicine is shelving its only clinical-stage gene therapy asset, PM359, despite promising early clinical data showing safety and efficacy in chronic granulomatous disease (CGD)245.

The first patient dosed with PM359 in a phase 1/2 trial experienced no serious adverse events and demonstrated restoration of NADPH oxidase activity in 66% of neutrophils by Day 30, above the threshold for clinical benefit25.

The company will pivot its pipeline focus to liver disease and externally partnered programs, and is exploring options to outlicense PM3595.

Prime Medicine's stock price has declined by 91%, reflecting broader challenges in the biotech and gene editing sector1.

Prime Medicine was initially launched in 2019, based on CRISPR-based 'prime editing' technology designed for highly precise genome editing12.

Sources:

1. https://www.statnews.com/2025/05/19/gene-editing-biotech-company-prime-medicine-announces-layoffs-ceo-departure/

2. https://www.fiercebiotech.com/biotech/prime-medicines-ceo-exits-biotech-shelves-sole-clinical-gene-therapy-lays-staff

3. https://investors.primemedicine.com/news-releases/news-release-details/prime-medicine-announces-strategic-restructuring-focus

4. https://www.biopharmadive.com/news/prime-medicine-restructure-layoff-gene-editing/748470/

5. https://www.genengnews.com/topics/genome-editing/prime-medicine-chops-25-of-workforce-pivots-pipeline-as-ceo-quits/