Pfizer Finds New Owner for Discontinued Cancer Drug in Deal Worth Up to $1 Billion

Pfizer has found a new owner for an antibody-drug conjugate (ADC) it acquired during an acquisition and later discontinued.

According to Fierce Biotech on the 4th (local time), Medicus Pharma signed an agreement to acquire rights from Pfizer to the ADC candidate PF-08046031. The drug targets CD228, a protein highly expressed in solid tumors, including melanoma.

Medicus Pharma will pay $12 million upfront when the agreement is signed and an additional $15 million on Sept. 2, 2027, the first anniversary of the agreement. The terms were disclosed in a filing with the Securities and Exchange Commission (SEC).

If the ADC reaches the market, Pfizer will receive royalties and could collect more than $1 billion in additional development, regulatory and sales milestone payments. Pfizer also provided $2 million to support Medicus Pharma’s early research.

Under the agreement, Medicus Pharma will be responsible for development, but must submit its development plans and budgets to Pfizer for review. Pfizer also has the option to fund all or part of the product’s development costs after the start of a pivotal clinical trial.

“This agreement is a defining milestone for Medicus and significantly expands our position in precision oncology,” Medicus Pharma CEO Raja Bukhari said in a statement to Fierce Biotech.

No drugs targeting CD228 have been approved. The phase 1 trial of PF-08046031, which Pfizer discontinued, began in May 2025 and explored the drug primarily in advanced melanoma, as well as lung, head and neck, and esophageal cancers.

Pfizer has continued to divest related assets since its $43 billion acquisition of Seagen in 2023. More recently, another ADC acquired in the same deal failed in a phase 3 lung cancer trial, marking the first pivotal clinical result for an asset from Seagen.