In 2016, Tecentriq became the first-in-class PD-1/L1 drug to gain approval for the treatment of advanced bladder cancer as a monotherapy for frontline chemotherapy-failure, relapsed/refractory patients. For decades, second-line bladder cancer treatments consisted of various chemotherapies, and the intent of treatment was largely palliative. With the introduction of Tecentriq, roughly 20% of second-line patients now have hope of achieving a durable response, and with that promise, the drug quickly became the standard of care in the second-line setting.

Fast forward to 2018, and rapid-fire approvals have resulted in five marketed PD-1/L1 drugs becoming available in the advanced bladder cancer space. Out of the pack, it is surprisingly Keytruda, and not Tecentriq, that has achieved front-runner status, and according to key opinion leaders (KOLs), has the potential to continue its winning streak in the coming years.

Keytruda’s success so far in bladder cancer is linked not only to clinical efficacy, but also partially to circumstance. The unexpected and devastating failure of what was supposed to be Tecentriq’s confirmatory trial gave Merck & Co. valuable catch-up time to produce its own level one data for Keytruda. As it stands currently, Keytruda is the only PD-1/L1 to have shown overall survival benefit in the second-line setting in a Phase III trial with chemotherapy as a comparator, making it an obvious choice for front-runner status in the PD-1/L1 class.

Merck’s development strategy for Keytruda

To help Keytruda stay ahead of the pack, Merck has a strong development strategy for the drug that sees it being tested in pivotal trials in combination with chemotherapy in the first-line setting, and in combination with Incyte’s IDO1 inhibitor, epacadostat, in both the frontline cisplatin-ineligible and second-line settings.

Of these pairings, it is the IO + IO combination of Keytruda + epacadostat that has generated the most excitement with KOLs. The preliminary data from this combination have shown a reasonable 35% response rate, but KOLs believe the key to its success lies in its favourable safety profile. With a median age of diagnosis of 70, bladder cancer patients tend to be elderly, with comorbidities including renal disease or smoking-related illnesses. For such a patient population, often the primary concern is not clinical efficacy, but tolerability. This is an aspect in which the Keytruda + epacadostat combination has thus far shown significant superiority over the other IO combinations being tested in bladder cancer, including PD-1/L1 + chemotherapy and PD-1/L1 + CTLA-4.

Furthermore, the fact that epacadostat is an oral treatment increases convenience and allows for continuous dosing, which is another differentiator. If the pivotal KEYNOTE-672 and -698 trial data are positive, KOLs predict widespread use of Keytruda + epacadostat across lines of therapy. Though these trials are still a few years from completion, Merck has certainly positioned Keytruda for continued success in bladder cancer.

Related reports

GlobalData (2017). OpportunityAnalyzer: Bladder Cancer – Opportunity Analysis and Forecasts to 2025, April 2017, PHARMADOA52894.