Prime Medicine to deprioritize CGD programs, reduce headcount by 25%

Prime Medicine (PRME) announced a strategic restructuring, including the deprioritization of its Chronic Granulomatous Disease programs, as well as a cost and workforce reduction to focus on its liver franchise and programs funded through external partnerships. Prime Medicine is currently advancing in vivo programs to cure two of the largest genetic liver diseases, Wilson’s Disease and Alpha-1 Antitrypsin Deficiency, with initial clinical data from both programs expected in 2027. Prime Medicine will also continue its in vivo Cystic Fibrosis program with support from the Cystic Fibrosis Foundation, and its efforts to develop Prime Edited CAR-T products for hematology, immunology and oncology in partnership with Bristol Myers Squibb. In addition, Prime Medicine will continue to pursue additional business development opportunities to accelerate innovation, ensure the broadest application of Prime Editing, and further bolster its financial resources. Prime Medicine will focus its internal efforts on the development of in vivo programs for the treatment of Wilson’s Disease and AATD, two of the largest genetic liver diseases. Prime Medicine expects to file an investigational new drug and/or clinical trial application for its Wilson’s Disease program in the first half of 2026 and for its AATD program in mid-2026; initial clinical data from both programs are expected in 2027. Wilson’s Disease: Wilson’s Disease is a rare and severe disorder caused by excess copper accumulation in the liver and brain that can lead to liver failure and neurocognitive decline and can be fatal without a liver transplant. There are currently no approved disease-modifying therapies for Wilson’s Disease, which affects more than 20,000 people in the United States and European Union. AATD: AATD is a progressive, genetic disorder caused by mutations in the SERPINA1 gene, which can result in both lung- and liver-related symptoms, including shortness of breath, wheezing, chronic cough and frequent chest colds, as well as jaundice, ascites, and cirrhosis. There are currently no disease-modifying or curative treatments approved for the approximately 200,000 people in the United States and European Union with AATD, of which 20,000-30,000 people are currently diagnosed. Many patients with AATD ultimately progress to liver failure or severe lung disease, eventually resulting in premature death. Prime Medicine will also continue its in vivo Cystic Fibrosis program with support from the Cystic Fibrosis Foundation, and its efforts to develop Prime Edited CAR-T products for hematology, immunology and oncology in partnership with Bristol Myers Squibb. As announced in conjunction with initial data for PM359 this morning, Prime Medicine is exploring options for the continued clinical development of PM359 external to the company and ceasing further efforts in X-linked CGD. Prime Medicine believes PM359 has the potential to transform the care of p47phox CGD and is committed to working with urgency to identify an appropriate partner to help ensure this important therapy is delivered to patients.Alongside the pipeline prioritization announced today, Prime Medicine is undertaking cost reduction measures and restructuring its team, including reducing its organizational headcount by approximately 25% percent. These initiatives are designed to significantly decrease Prime Medicine’s operating expenses and cash burn, reducing anticipated cash needs by almost half through 2027. Prime Medicine announced that it recently engaged in binding arbitration proceedings with Beam Therapeutics regarding the parties’ 2019 Collaboration and License Agreement and specific to its AATD program. Prime Medicine is committed to honoring the terms of the Agreement, and confident that it has the rights to pursue AATD under the Agreement. Based on its current plans, Prime Medicine continues to expect that its cash, cash equivalents and investments as of March 31, 2025 will be sufficient to fund its operations and capital expenditure requirements into the first half of 2026.