How Do Recent Deaths Impact Gene Therapy Development?

Cell and gene therapy (CGT) is among the most closely watched areas in pharma and biotech.

- Ayesha Siddiqui

As of June 2024, 100 products have been approved globally, with 2,848 candidates in the pipeline ranging from preclinical to preregistration phases, according to Citeline. But recent patient deaths have put the sector under scrutiny, leading to trial pauses and raising questions about the safety of some widely used delivery technologies. Would these shake development efforts or dampen investor and regulatory confidence in the field? Let's find out.

Cell and gene therapy, long hailed as one of the most promising frontiers in modern medicine, has offered hope of life-changing treatments for patients with rare and serious diseases.

The safety concerns began in March 2025, when Sarepta Therapeutics reported the first patient death linked to its approved Duchenne muscular dystrophy gene therapy, Elevidys. The non-ambulatory boy developed acute liver failure after receiving the treatment. In June 2025, a second non-ambulatory patient died following Elevidys treatment, prompting Sarepta to introduce a series of safety measures, including adding a black box warning to the product label. In May 2025, Rocket Pharmaceuticals disclosed the death of a participant in a small trial of its gene therapy for Danon disease, a rare genetic condition that weakens the heart muscle and typically kills male patients in early adulthood.