CHICAGO--With the company's R&D reputation riding on the line, Merck ($MRK) has begun posting positive results from a slate of early-stage studies of its immuno-oncology star pembrolizumab--MK-3475--which are beginning to demonstrate just how promising this therapy can be for a range of cancers beyond the initial focus on melanoma.
New data presented at ASCO also underscore just how durable a patient's response can be. And the pharma giant won't be waiting to get final results from these anti-PD-1 studies before rushing straight into Phase III trials that can be used to gain regulatory approvals that can extend to frontline cancer patients.
In one of its most advanced studies, investigators found that 69% of the advanced melanoma patients taking the PD-1 therapy were alive at the one-year mark, with 74% of patients previously untreated with Yervoy making it to the 12-month milestone. A total of 65% of the patients whose disease had progressed following treatment with Yervoy were also alive after one year.
In a separate study, a group of previously untreated patients with non-small cell lung cancer, pembrolizumab triggered a 47% response rate. And for another group of evaluable patients with one post baseline scan, the response rate was 80%. The median figure for the duration of response still hasn't been determined in the study, with some patients being treated for up to a year now. The lung cancer data in Phase Ib sets the stage for a pivotal Phase III study that Merck plans to start in the fall of this year.
In an early snapshot of a study for tough cases of advanced head and neck cancer, investigators have seen a 20% overall response rate, prompting them to add more patients to the study while also laying plans to hustle into a late-stage study aimed at winning approval to widen the drug's commercial opportunity.
"These are rather remarkable results," noted Roy Baynes, Merck's oncology R&D chief, in an interview with FierceBiotech. The new batch of data highlight a high response rate for a drug that also promises to have an "incredibly durable," or long-lasting, impact on patients. As for the lower rate of responses for head and neck cancer, Baynes underscored that investigators nailed down a disease control rate of 50%, adding that they were likely to continue to see responses develop as that trial proceeds.
ISI's Mark Schoenebaum called the head and neck data "encouraging" but a bit premature to get a good picture of its potential.
"The overall response rate was 20%, which is higher than the low/mid-teens response rate observed with Erbitux in a similar setting," Schoenebaum wrote in a note to investors. "The responses appear durable, but the data is quite immature so concrete durability conclusions also aren't possible. Neither OS nor PFS data were presented (data too immature), and, as you probably know, the field is shifting away from an emphasis on response rates to an emphasis on OS for immunotherapies. Note that historical OS in this population is around 13 months."
It's hard to overestimate the importance of MK-3475 to Merck, which has endured a lengthy drought of significant new drug approvals. The company is investing hundreds of millions of dollars to hang on to its leading role in the field, with rivals at Bristol-Myers Squibb, Roche and now AstraZeneca all rushing to stake a claim to a new drug arena that could be worth anywhere from $25 billion to $35 billion a year, depending on which of the most optimistic analyses you're looking at. Merck is now studying its immuno-oncology drug in some 30 tumor types, and it's been rapidly ramping up combo studies to match this immunotherapy with targeted cancer treatments.
Merck recently wrapped up its rolling FDA submission of pembrolizumab for melanoma, angling to be the first to arrive at the market with this drug. The agency has dubbed this drug a "breakthrough," warranting swift action by regulators. The PDUFA date is October 28.
- here's the release on head and neck cancer
- here's the longer-term survival data
- here's the release on lung cancer