Pfizer punts Seagen ADC, further muddying value of the $43B buyout

 

The co-development deal comes after Pfizer reported a late-stage failure for a Seagen asset and the discontinuation of another investigational therapy developed by the company as a subsidiary of the pharma.

Pfizer has cast off another asset from it’s $43 billion dollar acquisition of Seagen, with the pharma this time signing over primary responsibility for an investigational antibody-drug conjugate to Medicus Pharma.

Medicus has agreed to pay $12 million upfront for the asset, dubbed PF-08046031, according to a Sept. 2 SEC filing. The Pennsylvania biotech is also on the hook for a one-time $15 million payment on the first anniversary of the agreement, as well as certain development, regulatory and sales milestones that could bring the total deal value past $1 billion if realized. Pfizer could also receive tiered royalties on annual net sales of the antibody-drug conjugate (ADC).

Despite ceding authority to Medicus, Pfizer appears to want to retain a substantial degree of control in the development of PF-08046031. Under the terms of the license agreement, the pharma gave Medicus a one-time, non-refundable $2 million commitment to kickstart its activities for the ADC therapy, which the biotech is “required to apply solely to fund” PF-08046031.

Pfizer will also receive Medicus’ development plans for the asset and “has the right to review and comment on those plans” as well as meet with the biotech’s team to discuss PF-08046031, according to the securities document. Medicus is also required to submit “periodic progress reports” for the program to Pfizer.

The star of the deal, PF-08046031, is an early-stage ADC that targets melanotransferrin, a known antigen associated with melanoma that has since also been linked to other solid tumors. The molecule joined the Pfizer fold in 2023, with the pharma’s massive acquisition of Seagen.

Despite some early clinical successes—including a Phase 3 win in March 2024 for the ADC Adcetris in diffuse large B cell lymphoma—the confidence in Pfizer’s Seagen gamble has grown shakier in recent years. In June, a closely watched ADC sigvotatug vedotin delivered disappointing performance in a Phase 3 non-small cell lung cancer study, unable to significantly boost overall survival versus docetaxel.

Then, a few weeks later, Pfizer quietly axed SGN-MesoC2, another Seagen-linked asset that the pharma had been developing for solid tumors. As a Pfizer subsidiary, Seagen ran a Phase 1 study of SGN-MesoC2.

But the disquiet over the Seagen acquisition started much earlier. Activist investor Starboard Value cited the takeover as one of the reasons behind its challenge to the pharma’s leadership, according to an October 2024 presentation that has since been taken down. Starboard also took issue with Pfizer’s $5.4 billion acquisition of Global Blood Therapeutics, which similarly dealt several clinical disappointments. Pfizer “significantly overpaid” for both of these deals, the investor said at the time.

https://www.biospace.com/deals/pfizer-punts-seagen-adc-further-muddying-value-of-the-43b-buyout