20 Facts You Should Know About Immunotherapy Treatment

FACT #16:Immunotherapy is the only treatment approved to combat tumors, regardless of where they originate.

On May 23, 2017, the FDA approved pembrolizumab, an anti-PD-1 checkpoint immunotherapy, without restrictions based on the tumor's location. Instead, its approval hinges on the tumor's genetic stability.

Now, individuals with metastatic cancer showing genetic instability (identified by the MSI-hi or dMMR biomarker) can receive this immunotherapy, even if other treatments haven't been effective. In the clinical trial leading to this approval, patients with fifteen different tumor types were included, and nearly 40% responded positively. These tumors are often receptive to immunotherapy because their high DNA mutation rates produce abnormal proteins (neo-antigens) that the immune system recognizes as foreign.

In some cases, immune cells have already initiated a response against these neo-antigens but become exhausted via the PD-1/PD-L1 pathway. Here, a checkpoint immunotherapy blocking this pathway can tip the balance in favor of the immune system and the patient.