Shortly after osimertinib was approved for patients with non–small cell lung cancer in 2020 by the Food and Drug Administration, a patient came to me with increasing shortness of breath. He had been on erlotinib (Tarceva) for about 2 years and had done well. Nearly all of his pulmonary lesions had resolved and he was feeling well. He enjoyed boating in the summer and visiting grandkids in California in the winter. However, on this day, it was different. He was losing weight; he was tired and didn’t feel strong enough to put his boat in the water that spring. Long story short: We ordered a CT scan and all of his lesions were progressing. Since osimertinib had just been approved, we got a second biopsy, hoping that his insurance would pay for it. It did and sure enough, a new T790M mutation was present. He was on osimertinib for another 2 years before progressing and starting chemotherapy.
Second biopsies increasingly routine
The practice of ordering a second biopsy for patients with non–small cell lung carcinoma (NSCLC) was not common practice until after 2015 when the Food and Drug Administration approved gefitinib, a tyrosine kinase inhibitor (TKI) for patients whose tumors have epidermal growth factor receptor (EGFR) exon 19 deletions or exon 21 (L858R) substitution mutations.
Dr. Joan H. Schiller
Up until then, second biopsies were not routinely done for lung cancers. But with the advent of targeted therapy and new drugs designed specifically to tackle first- and second-line treatment resistance mutations, rebiopsies have become a necessity for patients with progressive disease.
Epidermal growth factors, including HER2, ErbB2, and MET, are receptors of tyrosine kinases that control cell growth, but when in overdrive, they can lead to the development of cancers, including lung adenocarcinoma, conventional glioblastoma multiforme, glioblastoma, colon adenocarcinoma, and NSCLC.
EGFRs date back to 1962 with their discovery by Stanley Cohen. The discovery was so important that in 1986, Mr. Cohen was awarded the Nobel Prize in physiology or medicine for the discovery along with Rita Levi-Montalcini.
Now, many years later, we finally have a string of new approvals for mutations in the EGF family of receptors and several under study.