Astellas and Seattle Genetics impressed Wall Street last fall when their combination of Padcev and Merck’s Keytruda fought off advanced bladder cancer in previously untreated patients. Friday, the partners presented updated results that look even better.
They might even be good enough to snag an expedited regulatory review, analysts say—and at least one market-watcher hiked his peak sales estimate for Padcev to $5.8 billion after the data release.
At the 11.5 month-mark of a phase 1b/2 study, the pairing had provoked a response in 73.3% of patients ineligible for cisplatin chemo, the companies said in a Friday morning presentation at the American Society of Clinical Oncology’s Genitourinary Cancers Symposium.
Some 15% of those patients showed a complete response—i.e., no signs of cancer activity—and the median duration of response hadn’t been reached. But 83.9% of patients had seen their benefit last at least six months at the time of analysis, and 53.7% had seen their benefit last at least a year.
Overall, patients went a median 12.3 months without their cancer worsening, and 81.6% of patients were still alive at the one-year mark.
The data follow up on results presented at September’s European Society for Medical Oncology annual meeting, where the partners showed the tandem had shrunk tumors in 71% of patients and wiped them out completely in 13%.
“Now that the data is more mature, this gives us a very reassuring look in terms of how” the combo “is able to maintain those responses that we’re seeing,” Andrew Krivoshik, M.D., Ph.D., Astellas senior vice president and head of oncology, said.
Analysts were upbeat on the news, too, with JPMorgan’s Cory Kasimov remarking in a note to clients that the “initial duration data bodes well for the combo vs. Keytruda monotherapy.” Leerink Partners’ Andrew Berens, meanwhile, updated his peak sales projection for Padcev to $5.8 billion from $3.8 billion “to reflect the better-than-expected durability.”
Padcev, after a mid-December FDA approval, is for now cleared only for use as a monotherapy in bladder cancer patients who have already received chemo and a checkpoint inhibitor from the PD-1/PD-L1 class. But the way analysts see it, a front-line OK for the combo may not be too far off.
“We believe the companies could leverage this dataset for potential accelerated approval,” Berens wrote.
Astellas’ Krivoshik, for his part, couldn’t say much on the matter except that, “as always, we work very closely with our regulatory partners in terms of trying to bring areas that have high unmet need new and novel medicines forward as quickly as possible.”
“It’s part of the ongoing dialogue and what we always do with global regulators,” he added.