FDA Halts Poseida Therapeutics' Prostate Cancer Drug Trial After Patient Dies; Shares Tank 35%

(RTTNews) - Shares of Poseida Therapeutics Inc. (PSTX) tanked 35% on Monday after-hours as the biotech drug maker announced that safety trial for a prostate cancer drug had been halted because of a patient's death.

In a Securities and Exchange Commission filing, Poseida said the Phase 1 clinical trial for P-PSMA-101 in metastatic castrate resistant prostate cancer has been placed on clinical hold by the U.S. FDA.

The patient in question had metastatic castrate-resistant prostate cancer, had failed treatment with multiple anti-cancer agents and was treated with P-PSMA-101 in late July. Through the first 7 days post-treatment, the patient had normal lab results and no clinical symptoms indicating an adverse event. The patient missed both his Day 10 and Day 14 follow up visits, but during this time developed symptoms that subsequently lead to hospitalization and he died of hepatic failure at Day 19 post-treatment.

The company said it is awaiting a formal response from the FDA and is preparing recommendations designed to allow resumption of the clinical trial. Once the FDA's questions are answered and a plan submitted, the FDA then has 30 days to notify the Company if the clinical study of P-PSMA-101 may be resumed.

PSTX closed Monday's trading at $13.00, down $0.10 or 0.76%, on the Nasdaq. The stock further dropped $4.53 or 34.85% in the after-hours trade.