FDA approves Seagen-Astellas bladder cancer combo

April 4, 2023

Japan-based Astellas Pharma, and U.S. biotech Seagen, announced this week that their combination drug received accelerated approval from the FDA for the treatment of advanced or metastatic urothelial cancer.

The treatment combines an antibody drug conjugate, Padcev, and Merck's PD-1 inhibitor blockbuster, Keytruda to offer a first in line alternative for patients who are not eligible to receive cisplatin-containing chemotherapy. Patients may be ineligible to receive cisplatin-containing chemotherapy due to various health conditions or pre-existing factors that make them more vulnerable to the drug's side effects, such as kidney damage, hearing loss, nausea or vomiting. Approximately 8,000 to 9,000 patients in the U.S. with advanced or metastatic urothelial cancer cannot receive this type of chemotherapy, according to Astellas. 

The approval was based on data from the phase 1b/2 EV-103 clinical trial, which showed a confirmed objective response rate of 68% and a median duration of response of 22.1 months in Dose Escalation/Cohort A. There is a phase 3 confirmatory trial underway. 

Keytruda was first approved by FDA in September 2014 for the treatment of advanced melanoma. Since then, it has been approved for the treatment of several other types of cancer, including non-small cell lung cancer, head and neck squamous cell carcinoma, classical Hodgkin lymphoma and urothelial carcinoma. Padcev was granted accelerated approval by the agency in 2019, for the treatment of adult patients with locally advanced or metastatic urothelial cancer who have received prior treatment with a PD-1/L1 inhibitor and platinum-containing chemotherapy. It was granted full approval in 2021. 

The combination therapy was given Breakthrough Therapy designation and Priority Review by the FDA in 2020, and was granted accelerated approval as part of the FDA's Accelerated Approval Program, based on surrogate endpoint data, due to its potential to treat an unmet medical need for a serious condition.

Merck has been tied to Seagen since Oct. 2020, when the drugmaker made $1 billion equity investment in the Seattle biotech. While rumors of a potential $40 billion buyout began circulating back last July, Bloomberg later reported that the conversation had stalled because the two couldn't agree on a price. A few weeks ago, Pfizer acquired Seagen for $43 billion.