09:02 AM EDT, 07/07/2025 (MT Newswires) -- Jasper Therapeutics ( JSPR ) said Monday it is shutting down its asthma trial after discovering a faulty batch of its experimental drug was used to treat individuals who were enrolled in a trial evaluating briquilimab.

The company also said it is halting development in severe combined immunodeficiency and may restructure operations to cut costs and preserve cash.

Jasper also said the same drug batch impacted results in certain patient groups in its chronic hives studies, and those groups will be retested using a different batch.

Most patients given single doses of briquilimab in the early-stage study saw full symptom relief, and about 73% in a follow-up group treated every eight weeks achieved similar results after 12 weeks, the company said.

No serious safety issues were reported in the studies, and most side effects were described as mild and temporary, Jasper said

Shares of the company were down by more than 64% in recent Monday premarket activity.