Anne S. Tsao, MD of MD Anderson Cancer Center discusses Osimertinib in front-line for EGFR mutated resistance mechanisms and how they are not fully understood.
New data of Osimertinib showing with progression free and overall survival benefit in the front-line setting, Dr. Tsao is giving Osimertinib for newly diagnosed EGFR mutated patients. However, the resistance mechanism for patients who receive Osimertinib front-line is not yet fully understood.
There are reports that the C797S mutation maybe important and more data is needed to know whats the best treatment for those who are refractory to Osimertinib. One can always do chemotherapy and subsequent other therapies, like the EGFR targeted therapy or clinical trials with EGFR targeted agents. For Dr. Tsao she reserves immunotherapy for further down the line for EGFR oncogenic driver mutated patients.
For her patients who are currently on first generation EGFR TKI, Dr. Tsao is not switching to Osimertinib if they respond very well. So, she is following the standard protocol for these patients when patients are in first generation or second generation, testing them when they progress to see their resistance mechanism. If patients have T790, Osimertinib will be the best. However, if they have other oncogenic driver mutations, another specific agent should be fit for them. On the other hand, if patients have progressional disease, its very important to go with chemotherapy or if its slow growth, Dr, Tsao suggest Bevacizumab to the first and second generation EGFR TKI patients to control their disease.