- Adding Merck & Co.'s immunotherapy Keytruda to treatment with other drugs helped patients with advanced cervical cancer live longer and kept their disease from returning for longer than those other drugs alone, the company announced Tuesday.
- The new finding, which comes from an interim review of a Phase 3 clinical trial, could help Merck secure a full approval for Keytruda for cervical cancer treatment. The Food and Drug Administration granted the drug a conditional approval in 2018 based on remission data.
- Notably, Merck said the data were positive regardless of whether patients' tumors expressed a certain protein that Keytruda targets. The accelerated approval was only for patients who tested positive for the protein, called PD-L1.
As drugmakers have expanded the use of cancer immmunotherapies like Keytruda, they have often first sought approval based on the drugs' ability to shrink tumors. Typically, the FDA then requires companies to confirm treatment can stave off disease and help patients live longer.
That hasn't always happened, though, with confirmatory trial delays in some cases and negative results in others. Recently, several drugmakers, working with the FDA, agreed to withdraw four accelerated approvals previously granted to cancer immunotherapies. Agency advisers in April recommend doing so for two more in a high-profile meeting with the regulator.
In this case, the FDA will likely have enough evidence to convert Keytruda's accelerated cervical cancer approval into a full one. Merck said the independent safety monitoring board for the trial, called KEYNOTE-826, determined Keytruda will meet the study's primary goals of overall survival and progression free survival.
The trial enrolled 617 patients who had never been treated with a systemic therapy like chemotherapy and weren't eligible for a curative approach like surgery or radiation. All patients received chemotherapy and sometimes Avastin, while some were also given Keytruda in addition to determine whether adding Merck's drug could lengthen survival.
Merck didn't disclose full data, but said it will present them at an upcoming medical meeting.
Full approval, should the FDA grant it, could represent a significant expansion of Keytruda's label in this setting. The accelerated approval currently only permits Keytruda's use in patients who have progressed on chemotherapy and whose tumors express the protein PD-L1. Cell signaling via that protein allows tumors to escape attack by immune cells, a process which Keytruda disrupts by blocking a related immune cell protein.
This trial showed Keytruda benefited all patients regardless of PD-L1 status. Cancer specialists, however, will likely want to see separate data from PD-L1-positive and PD-L1-negative patients to determine how well the drug works specifically in the latter group.
Currently, Keytruda is the only checkpoint inhibitor that's cleared for use in advanced cervical cancer.
Roche's Tecentriq is being tested in a Phase 3 trial with chemo and Avastin, while Regeneron's checkpoint inhibitor Libtayo is also in a Phase 3 trial as a single agent being compared to placebo. Opdivo, from Bristol Myers Squibb and Keytruda's main rival, is not in Phase 3 testing in cervical cancer.
Widening use of Keytruda could help Merck further cement the drug's status as the top-selling immmunotherapy. Currently, Keytruda outsells Opdivo and Tecentriq by a two-to-one or greater margin.