Pyrotinib as a salvage treatment for patients with HER-2 positive advanced lung adenocarcinoma after the progression of afatinib treatment.

Background: The efficacy of afatinib or pyrotinib has been demonstrated in HER2-positive advanced non-small cell lung cancer (NSCLC) patients; however, the efficacy of pyrotinib after afatinib progression has yet to be determined.

Method: Patients with HER2 mutated advanced lung adenocarcinoma administered afatinib or pyrotinib monotherapy were enrolled. Those who received pyrotinib after afatinib were further analyzed to determine the efficacy and safety of pyrotinib after progression on afatinib. Survival curves were plotted with the Kaplan-Meier method. A swimming plot was used to describe the specific treatments. Additionally, patient-derived tumor organoids (PDTOs) were established from HER2-amplified NSCLC patient samples to investigate the antitumor activity of pyrotinib in HER2-amplified tumor cells in vitro.

Results: A total of 99 patients were enrolled, 13 of whom were administered pyrotinib after progression on afatinib. No statistical difference in PFS of pyrotinib was observed between patients whether be treated after afatinib progression or not (6.7 months vs. 4.4 months, P = 0.817), thus indicating that progression on afatinib did not affect the efficacy of pyrotinib. Further analysis was conducted on the former patients, which comprising eight patients administered interval chemotherapy after progression on afatinib. Two patients achieved PR after pyrotinib treatment. No independent factors were found to influence the PFS of pyrotinib. PDTOs confirmed the anti-tumor activity of pyrotinib in NSCLC tumor cells with HER2 amplification.

Conclusions: Progression after prior afatinib treatment does not influence the efficacy of pyrotinib treatment. Pyrotinib may be a salvage option for patients with HER2 mutation who have experienced progression on afatinib.