Seagen, Astellas' Padcev snares full approval and expands into 2nd-line treatment on path to blockbuster land

Padcev
Seagen and Astellas hope to move Padcev into front-line treatment by combining it with Merck's immuno-oncology superstar Keytruda. (Seattle Genetics)

That didn't take long: Shortly after Seagen and Astellas Pharma's Padcev nabbed a priority review for two bladder cancer applications, the FDA has returned with double green lights—and it's given the OK more than a month ahead of schedule. 

First up, Padcev's conditional nod in third-line metastatic or locally advanced bladder cancer has been converted into a full approval. Until now, the drug has carried an accelerated approval to treat patients who've already received platinum-based chemotherapy and a PD-1/PD-L1 checkpoint inhibitor.

At the same time, the FDA blessed the antibody-drug conjugate's move into earlier bladder cancer treatment as a second-line therapy for adults who are ineligible for cisplatin-based chemotherapy. 

“Almost half of advanced bladder cancer patients cannot receive cisplatin-based chemotherapy," Evan Yu, M.D., a member the University of Washington School of Medicine's oncology division and lead investigator for Padcev's EV-201 study in cisplatin-ineligible patients, said in a statement. Many of those patients receive an immunotherapy first, and if that treatment falls short, they're left with few other options, he said. 

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Padcev's swift trip through the FDA came courtesy of the agency's Real-Time Oncology Review pilot, which aims to hasten reviews for certain cancer meds so they can reach patients faster. The regulator handed Seagen and Astellas' Padcev applications a priority review tag in April and wasn't expected to make a decision until Aug. 17. 

The FDA granted its full approval on data from the partners' late-stage EV-301 trial, which showed at the time of a prespecified interim analysis that patients treated with Padcev lived a median of 3.9 months longer than those on chemotherapy. Specifically, the Padcev arm yielded a median overall survival time of 12.9 months versus the chemotherapy cohort's nine months, Seagen and Astellas said. 

As for the second-line green light in cisplatin-ineligible patients, data from a second cohort from Padcev's EV-201 study showed the drug triggered a response in 51% of patients after a median follow-up of 16 months. Those responses lasted for a median of 13.8 months, Seagen and Astellas said. 

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Padcev's new approvals put the drug one step closer to its blockbuster ambitions. SVB Leerink's Andrew Berens has said the med could hit $1.32 billion in peak sales across all its potential nods in previously treated bladder cancer. Meanwhile, Wall Street predicts that number could swell to $2.8 billion in 2030—provided Padcev makes its way up the treatment chain to newly diagnosed bladder cancer patients. 

To reach that goal, Seagen and Astellas are pairing Padcev with Merck's immuno-oncology megablockbuster Keytruda in a cohort of their phase 2 EV-103 trial, which is looking at cisplatin-ineligible patients. They're also eyeing front-line use with Keytruda in their late-stage EV-302 study, which is pitting the combo against chemotherapy in patients regardless of cisplatin eligibility.