By Ashley Brenton, PhD
One of the cornerstones of Precision Medicine is the concept of selecting a therapy based on the precise genetics of the patient. This is referred to as targeted therapy. In the case of cancer, this extends to looking at the genetic mutational profile of the tumor as well, and selecting cancer drugs that target the cancer at the genetic level of detail.
In May, the FDA approved the targeted cancer drug Keytruda (pembrolizumab), which is the first time approval has been granted for a medication that targets a specific genetic feature of the cancer, as opposed to a drug that targets a tumor in a specific body part. When describing cancer, it’s common to hear that one has breast cancer or prostate cancer or liver cancer; it’s not as common to hear that one has a microsatellite instability-high (MSI-H) or mismatch repair deficient (dMMR) tumor. Yet this detailed molecular knowledge can be more relevant for treatment. MSI-H and dMMR are biomarkers that indicate the cancer is highly genetically mutated. Keytruda unleashes the power of the immune system to fight highly mutated cancers by blocking a key process that normally limits the immune system in attacking one’s own cells (activation of the PD-1/PD-L1 cellular pathway).
Although Keytruda was previously approved for urothelial carcinoma, recurrent or metastatic head and neck cancer, metastatic melanoma, refractory classical Hodgkin lymphoma, and metastatic non-small cell lung cancer, under certain conditions, this is the first time a medication has been approved for cancers with a specific biomarker. Rapid approval was granted using the Accelerated Approval process, which allows the FDA to approve drugs for which there is a reasonable likelihood of clinical benefit. This approves medications without requiring companies to provide as much safety and efficacy evidence. However, companies are still required to conduct ongoing trials to evaluate safety and efficacy.
Following on the heels of this exciting approval, the Director of FDA’s Center for Drug Evaluation and Research, Janet Woodcock, M.D., posted an article lauding the advance of precision medicine. She states, “FDA helps bring precision medicine—in the form of targeted therapies—to people with diseases that have specific genetic features…Two recent FDA drug approvals point to an encouraging future for “precision medicine”—an approach for disease treatment that tailors medical therapies, including medications, to the needs of individual patients.” In addition to Keytruda, Dr. Woodcock mentions the expanded approval of Kalydeco (ivacaftor), a medication for cystic fibrosis. Prior to May, Kalydeco was approved for treatment of just 10 cystic fibrosis mutations; now 33 mutations are recognized.
Precision medicine is indeed the future of medicine and its advancement continues to improve patient care. It is exciting to see the FDA clearly on board with precision medicine, as Dr. Woodcock concludes her article by stating that, “FDA is actively pursuing more advances in targeted therapies.” SOTERIA is thrilled to be at the forefront of this medical revolution and to help patients decipher the often complicated story of precision medicine.
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Dr. Ashley Brenton is a precision medicine veteran. A classically trained molecular biologist, Dr.
Brenton’s career has focused on applying genomics to public health issues and she has a proven
track record in building scientific evidence for precision medicine, as well as bringing successful
precision medicine tests to commercialization. Dr. Brenton began her career at Johns Hopkins
and her background in public health and genomics led her to Soteria, where she strives to help
patients and their families navigate the often-complicated world of medicine through clear
communication and an expert understanding of cutting-edge medical testing.