Pfizer has ended development of a B7-H4-directed antibody-drug conjugate (ADC), triggering a $1 billion impairment charge. The Big Pharma disclosed the blow alongside a $200 million charge linked to another ADC.
The $1 billion charge is tied to B7H4V, an ADC that Pfizer acquired in its takeover of Seagen late in 2023. Seagen began a phase 1 trial of the ADC in people with advanced solid tumors in 2022. Recruitment stopped in September 2023 but resumed again the next month. Seagen stopped enrollment again in December 2024. Now, Pfizer has revealed the latest halt is permanent.
“We have made a business decision to discontinue the felmetatug vedotin (FV) development program based on clinical data generated to date indicating that FV is unlikely to achieve a meaningful improvement over standard-of-care chemotherapy in patients with advanced solid tumors, including triple-negative breast cancer," a Pfizer spokesperson said via email. "There have been no new safety signals observed in patients taking FV."
Pfizer talked up the prospects of the drug at an oncology day event 11 months ago, including the asset on a list of eight potential blockbusters that its pipeline could generate by 2030. The drugmaker used the event to tout early signs of antitumor activity in patients with two types of breast cancer: triple negative and HER-positive, HER2-negative. At the time, Pfizer was also targeting ovarian and endometrial cancer with the ADC.
B7-H4 is a competitive space. AstraZeneca and GSK have rival ADCs in the clinic. Other drug developers have aimed bispecifics at the target but that race has thinned out in recent years, with Pfizer and Genmab terminating programs.
Pfizer reported (PDF) the discontinuation of B7H4V as part of $2.9 billion in intangible asset impairment charges in its fourth-quarter results. Another ADC, disitamab vedotin, accounted for $200 million of the charges.
Seagen took the HER2-directed ADC into a phase 3 trial in people with previously untreated urothelial cancer in 2023. The ADC, which Seagen bought for $200 million upfront in 2021, works in the same way as Enhertu but AstraZeneca and Daiichi Sankyo’s blockbuster is yet to win approval for first-line use in urothelial cancer.
The $200 million disitamab vedotin impairment charge reflects the reality of “emerging competition,” Pfizer said in its financial filing. RemeGen, the biotech that licensed ex-Asia rights to Seagen, won approval for disitamab vedotin in China in 2021.
As part of its financials, the New York pharma also revealed it has "discontinued" phase 2 work on heart failure hopeful ponsegromab. The drug is still being tested in cancer patients with wasting syndrome to help them gain weight.