Bristol-Myers Squibb (BMY)’s Cellares Exit Raises Questions Over Breyanzi Growth

Bristol-Myers Squibb (BMY) has terminated its partnership with cell-therapy maker Cellares after discovering the Cellares Cell Shuttle platform could not meet the requirements for manufacturing Breyanzi at commercial scale. The $380 million partnership, announced in 2024, aimed to increase Breyanzi manufacturing capacity in the U.S., Europe, and Japan.

Breyanzi, a significant product for BMY generating $1.36 billion in sales in 2025, remains unaffected by the decision, as the termination applies exclusively to Cellares and its manufacturing platform. The move is seen as a way to maintain product quality and reliability, preventing potential supply or consistency issues as demand grows.

BMY maintains its commitment to Breyanzi and still has opportunities to expand the drug through its existing manufacturing network and other capacity investments. BMY also has other growth drivers, including the FDA accelerated approval of ZENBEXUS (iberdomide) for multiple myeloma. The termination highlights the challenges of scaling CAR-T manufacturing, which is complex and costly due to highly individualized processes.

The Cellares termination could force BMY to rely on alternative manufacturing arrangements or invest in additional internal capacity, which may take longer and cost more. Despite this, BMY's decision to prioritize safety and quality over a failed manufacturing partnership suggests disciplined capital allocation. The issue is specific to Cellares, not the drug itself, so the overall investment case for BMY remains intact as long as the company can find alternative capacity to support Breyanzi's growth.