Rechallenge chemotherapy with pemetrexed was shown to be efficient in malignant pleural mesothelioma; however, its role in non-small-cell lung cancer (NSCLC) has not been investigated. In this study, we retrospectively enrolled 31 patients with non-squamous NSCLC who had achieved disease control with initial pemetrexed treatment, followed by rechallenge with pemetrexed-based chemotherapy (PBC) upon disease progression. After the rechallenge, 5 patients (16.1%) achieved partial remission (PR), 17 (54.8%) achieved stable disease (SD) and 9 (29.1%) experienced progressive disease. The treatment was generally well tolerated, with a low rate of toxicity. The median progression-free survival (PFS) was 3.8 months with the rechallenge. Patients with a PFS of ≥10 months with initial PBC exhibited longer PFS and overall survival (OS) with the rechallenge compared to those with a PFS of <10 months with initial PBC (PFS: 6.2±0.33 vs. 3.1±0.26 months, respectively; P=0.011; and OS, 19.8±3.2 vs. 9.2±1.1 months, respectively; P=0.005). The time from the termination of initial PBC to disease progression was also associated with survival after the rechallenge. However, the response to initial PBC (PR vs. SD) did not affect PFS after the rechallenge. No significant differences were observed in thymidylate synthase expression, echinoderm microtubule-associated protein-like 4-anaplastic lymphoma kinase gene fusion, or epithelial growth factor receptor mutation status between pemetrexed-sensitive and pemetrexed-resistant patients. Our results demonstrated that rechallenge with PBC was well tolerated and survival after the rechallenge was associated with survival during initial PBC. Therefore, patients with a PFS of ≥10 months or time-to-disease progression ≥3 months may be considered as candidates for pemetrexed rechallenge.
Keywords: adverse effects; non-small-cell lung cancer; overall survival; pemetrexed; rechallenge.