Yesterday afternoon, the FDA granted accelerated approval to Merck’s anti-PD1 drug Keytruda, formerly known as MK-3475, for advanced or unresectable melanoma no longer responding to current therapies. I applaud the FDA’s swift approval, and believe that this decision marks a great turning point for immuno-oncology.
For decades, the promise of cancer immunotherapy has been well regarded. However, the development of such treatments has been held back by a lack of understanding and an absence of safe and effective technologies. As our understanding of tumor biology has expanded and evolved, we have come to realize a simple truth: if tumors use specific interactions to subvert the body’s immune system, we can manipulate these interactions to empower the immune system against cancer. Our enhanced understanding has shown us that a "precision" approach, using combined immunotherapies, is treating cancer the way nature intended. Keytruda’s swift approval serves as a major signal that this intention looks to be fully realized far sooner than many would think.
Keytruda is part of a class of drugs known as ‘checkpoint inhibitors,’ which act by inhibiting immune checkpoint interactions. These drugs are designed to block the tumors ability to exploit natural regulatory elements of the immune system – a method that tumors use to “hit the brakes” on an immune response. By counteracting this tactic, checkpoint inhibitors are able to “cut the brakes” on an immune response. Keytruda targets a regulatory element known as programmed cell death protein 1, or PD1. The first approved checkpoint inhibitor for melanoma, Yervoy, targeted a different element, known as CTLA4. While Yervoy has a response rate around 10%, Keytruda, along with similar next-generation of checkpoint therapies, have been reportedly able to generate response rates around 30-40% in the same patient population.
While this is a significant step forward, the situation remains such that a majority of late-stage sufferers will not respond to these potentially life-saving drugs. Even more, melanoma is classified as being one of the most highly immunogenic cancers. This means that as next-gen checkpoint inhibitors are approved and expanded to address a wide variety of tumor types, the responder population will constitute an even smaller proportion for most all other indications. I stand by my statement that the need for a transformative therapy, which is capable of converting checkpoint inhibitor non-responders into responders, will likely constitute the greatest unmet medical need of our generation. I believe that OncoSec’s ImmunoPulse platform has the potential to address this need, and allow the successes of these drugs to ring out to many more patients faced with life-threatening disease. Keytruda’s approval has done much to advance the realm of cancer immunotherapy. Now, it is our turn at OncoSec to build off this progress and act as a key contributor to the future of cancer therapy: a future that employs combination-based immunotherapy approaches to treat cancer the way nature intended.
The statements or opinions expressed on this site are my own and do not necessarily represent those of my employer OncoSec Medical.