Pfizer's breast cancer drug Vepdegestrant posts mixed results in key trial

By Damian Garde 

Pfizer Inc.’s next-generation treatment for breast cancer posted mixed results in a final-stage study, a potential setback for a drug the company once called a blockbuster in the making. 

The drug, vepdegestrant, failed to meaningfully delay cancer progression for all patients enrolled in the study but met its goals for a subset who have a specific genetic mutation, the company said in a statement Tuesday. Pfizer said it will share the results with health regulators to potentially support vepdegestrant’s approval.

 

Pfizer has included vepdegestrant on a list of eight potential blockbuster cancer medicines in its pipeline. If the treatment is approved only for breast cancer patients with the specific mutation, it would significantly reduce the future market size. Arvinas Inc., a biotech company, licensed vepdegestrant to Pfizer and is entitled to a share of profits.

 

Shares of Arvinas dropped more than 20 per cent in premarket trading in New York. Pfizer’s stock was little changed.

 

Pfizer is searching for new products to help arrest its post-pandemic decline and is betting heavily on new treatments for cancer. In 2023, Pfizer spent $43 billion on the oncology-focused Seagen Inc., and Chief Executive Officer Albert Bourla has repeatedly pointed to the company’s pipeline of cancer drugs as an under-valued source of future growth.

 

Vepdegestrant, a daily pill, is designed to complement Pfizer’s blockbuster breast cancer treatment Ibrance. The pivotal study enrolled 624 patients whose breast cancer persisted after treatment with Ibrance or a similar therapy. Half of the patients received vepdegestrant and half got injections of a standard hormone therapy called fulvestrant. Pfizer said it would present detailed results from the study at a future medical meeting.