Larotrectinib : A new weapon against cancer : Dr. Nilesh D. Mehta

At one time, designer drugs were being just talked about as a scientific curiosity. Cancer researchers have diligently figured out the actual mutations that are involved in some forms of cancer. While medical research has not been able to elucidate all the mutational mystery in cancer cells, there have been major milestones that have been achieved in the past decade. Particularly, we have seen use of check point inhibitors as medications used for cancer patients as immunotherapy particularly with lung cancer, colon cancer, bladder cancer, and the list continues to expand.

Until now, the emphasis for doctors was to find out where the cancer came from and then focus on therapy based on that. Now, there is going to be a paradigm shift in that thought process. We now want to know what mutation does the cancer possess regardless of where it arose. If we know the mutation that caused the cancer, then, we can selectively go after the mutated cancer cells and have a positive effect on patients.

Neurotrophic tyrosine receptor kinase (NTRK) gene abnormalities resulting in mutation affects cancer patients. This mutation that occurs appears to be the “driver” of these cancer cells allowing their propagation and multiplication. If we can successfully switch off the mutation, one would think that the cancer cells would not multiply. That is exactly what Vitrakvi appears to do. The Food and Drug Administration has approved this new cancer drug larotrectinib (Vitrakvi) that is the first medication to be designed from the start to treat a specific genetic mutation rather than a cancer type or from what organ cancer arose. Vitrakvi is indicated for the treatment of adult and pediatric patients with solid tumors that have this NTRK gene fusion without a known acquired resistance mutation. This treatment is meant for patients where other alternatives have already been explored. While the potential effects of this approval may not be far reaching in the immediate context, it is the concept which appears to be an innovative and exciting one.

We may be fast approaching an era where oncologists may not be that concerned about the actual organ from where cancer cells started (colon, breast, lung etc), but rather be more interested in the genetic make-up of the tumor. Specific and individual tumor mutations in cancer cells have been quite elusive and it has been only in the last decade or so that therapeutic values have been explored to help our patients with cancer.

NTRK genetic abnormalities are an extremely small portion of mutational defects identified in cancer patients. We have a drug that can target these specific patients with this abnormality. As more mutational abnormalities are discovered, specific targeted drugs will become available to treat cancer patients more effectively. This clearly sends a positive message to our patients who are always looking for newer treatments.

Dr. Nilesh D. Mehta
hiINDiA