Cargo Therapeutics Halts CAR-T Development After Safety Concerns, Announces 50% Staff Reduction
• Cargo Therapeutics is discontinuing development of its experimental CAR-T therapy following early trial data revealing three patient deaths and significant safety concerns in blood cancer treatment.
• The Phase 2 trial was terminated early after 18% of patients developed severe inflammatory syndrome IEC-HS, with only 18% of participants maintaining complete remission at 3 months.
• Despite raising over $500 million for cell therapy development, the company will lay off half its workforce while continuing to advance an alternative CAR-T treatment program.
In a significant setback for advanced cell therapy development, Cargo Therapeutics announced the discontinuation of its leading CAR-T therapy program following concerning safety data and limited efficacy results, leading to a 50% reduction in its workforce.
The company, established by prominent cell therapy researchers and a pediatric cancer advocate, had positioned itself as a potential solution for patients who relapse after initial CAR-T treatments. Despite raising over $500 million in funding, the company's ambitious plans have faced a serious obstacle.
The Phase 2 trial results revealed significant safety issues, with 18% of patients developing a severe inflammatory condition known as IEC-HS (Immune Effector Cell-Associated Hemophagocytic Syndrome). More alarmingly, the trial reported three patient deaths, prompting an early termination of the study.
Efficacy data proved equally disappointing, with only 18% of patients maintaining complete remission after three months of treatment. These results fell short of expectations, particularly given the promising early academic data that had initially supported the program's development.
CEO Gina Chapman addressed the situation, stating that while this specific program would be discontinued, Cargo Therapeutics will continue advancing another CAR-T treatment in its pipeline while evaluating strategic options for the company's future.
The development represents a significant setback in the field of CAR-T therapy, which has shown remarkable promise in treating blood cancers. Current market-approved CAR-T treatments can be curative for certain blood cancer patients, but options remain limited for those who experience disease progression or relapse.
This setback highlights the ongoing challenges in developing safe and effective cell therapies, particularly for heavily pretreated patients. The news may impact investor confidence in the broader cell therapy sector, which has seen substantial investment in recent years.
The company's decision to maintain development of its alternative CAR-T program suggests a strategic refocus rather than a complete withdrawal from the cell therapy space. However, the substantial workforce reduction indicates significant organizational restructuring ahead.

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Cargo to lay off staff after CAR-T data show safety concerns
statnews.com · Jan 30, 2025