Astellas (OTC:ALPMY)Seattle Genetics (NASDAQ:SGEN), and Merck (NYSE:MRK) have good news for new bladder cancer patients who aren't eligible for standard chemotherapy. Followup data from an ongoing clinical trial suggests that a combination of Padcev and Keytruda could become a new first-line treatment for this underserved group. 

Cooperation makes it happen

Keytruda from Merck is a protein that makes it hard for tumor cells to shut down the immune system when it attacks them. Padcev, from collaboration partners Astellas and Seattle Genetics, is a protein that delivers a dose of chemotherapy directly to tumor cells that present a telltale sign of malignancy on their surface called nectin-4.

Smiling physician

Image source: Getty Images.

Padcev earned approval in December as a treatment for bladder cancer patients whose tumors kept growing after treatment with Keytruda and similar drugs. Seattle Genetics had suggested getting Padcev into the mix with Keytruda at the same time would lead to better outcomes for patients, and Tuesday's data drop suggests this is the case.

Seattle Genetics previously released preliminary results that suggested the combination of Padcev and Keytruda was shrinking tumors. On Tuesday, Seattle Genetics and Astellas announced confirmed tumor responses from 33 of 45 patients treated with the combination, seven of whom achieved complete remission.

What matters most

Getting tumors to respond doesn't always lead to better outcomes. That's why the long-term commercial success of this potential combination therapy will depend on overall survival results. This study hasn't been underway for long enough to produce data on that score yet.

So far, we know that an impressive 82% of patients given the combination therapy were still alive 12-months after beginning treatment. If this number holds up for another year, Padcev plus Keytruda could become the new standard of care.