By: Terry Murdock, MS | January 31, 2017
How checkpoint inhibitors help targeted cancer therapies reach their destination – better patient outcomes.
At the forefront of recent advances in cancer treatment is the development of treatment paths that use small-molecule drugs and biologics to harness a patient’s own immune system to fight the tumor. An important function of the immune system is to recognize cells that are potentially cancerous and destroy them. On the surface of the cell are proteins, called checkpoint proteins, which tell the immune system a cell is healthy. Certain immune cells, T cells, also have checkpoint proteins which attach to the checkpoint proteins on normal cells; when these proteins bind it effectively tells the immune cell to leave the cell alone by acting as an off switch. Cancer cells can sometimes find ways to use these checkpoints to avoid being destroyed by the immune system.
Treatments that target these checkpoint proteins, known as checkpoint inhibitors, can boost the immune response against cancer cells, effectively taking the brakes off T-cells. Checkpoint inhibitors have shown great promise in treating certain cancers. Such advances are generating incredible excitement in the field of oncology, and giving hope to millions of cancer patients. The foundation has been laid and the momentum for immunotherapies as a mainstay in treatment options has been established; today people are living longer and fuller lives after the diagnosis of cancer.
These rapid advances have been driven in part by cross-industry collaborations among leaders from the biopharma community, academia, regulatory agencies, professional organizations, and private sector investors, who have the resources and passion to drive these discoveries forward. Creating environments in which disciplines such as immunology and cancer biology, as well as non-biological disciplines, can be brought together, to share ideas and brainstorm solutions has been key for driving this research forward. These collaborative efforts, combined with increases in the National Institutes of Health (NIH) funding for 2017 and the National Cancer Moonshot Initiative, have been key for success and lay the foundation for increased dialogue and attention around just how much work remains to accelerate the delivery of new cancer therapies to patients.
The recent progress can be exemplified by the fact in early 2015 checkpoint inhibitors had been approved by the United States Food and Drug Administration for treating one kind of cancer; by mid-2016 that had been expanded to five different types of cancer. However, most experts will agree that we have only scratched the surface: this is just the first wave for immunotherapy development, there is so much more to discover.
It should be noted here that we have seen these new immunotherapies do not work for all cancers and they come with side effects. In 2017 we expect that we will learn more about how to deliver these therapies in ways that minimize or avoid toxic side effects. It is also known that cancer cells inhibit different pathways that affect T-cell function, one reason why not all cancers respond to the currently approved checkpoint inhibitors. The good news is there are therapeutics currently in early clinical development which target other immune-evasion mechanisms. Combining them with other immunotherapies or more traditional methods such as surgery, radiation therapy, chemotherapy, and new therapies targeted at a specific mechanism is likely to be beneficial. It is not out of the realm of possibilities that some of these combination approaches may be approved from late 2017 to early 2018.