Clinical observation of Pemetrexed first-line treatment in advanced non-squamous lung cancer or non-small cell lung cancer without driver-mutations: a phase 2, single-arm trial.

Background: Non-dominant population, which means patients with advanced non-squamous lung cancer or non-small cell lung cancer (NSCLC) without driver-mutations, who are excluded from clinical studies because of specific baseline conditions refractory to multiple treatments, have poor outcomes. We assessed the activity of pemetrexed first-line treatment for a non-dominant population, explore the safety and efficacy of pemetrexed therapy.

Methods: We did this two-phased, single-arm trial at two sites at the Fifth Affiliated Hospital of Sun Yat-sen University and Guangxi medical university cancer hospital. Pemetrexed 500 mg/m, static drops on day 1; 21 days for a cycle, each treatment for at least two cycles and up to six cycles. Efficacy was assessed every two cycles.

Results: We counted the July 21, 2018 to 2020 on May 31, first diagnosed with IIIb-IV period (American Joint Committee on Cancer eighth edition) no drive genes, non-squamous cell carcinomas, 30 patients with non-small cell lung cancer, the follow-up to July 31, 2020, median follow-up time was 12 months. Most were elderly patients with poor general conditions (96.7% of patients had ECOG scores of 2-3) (median age 66 years). Median duration of maintenance treatment was 6 months. Median progression-free survival was 6.5 months. Median overall survival was 12 months. Patients with performance status =0-2 had a significantly higher median overall survival time (16 months) compared with patients with performance status =3 who had a median overall survival time of 7 months (P=0.001). Most treatment-related adverse events were grade 1 or grade 2.

Conclusions: This study is the first to investigate the survival benefit and toxicity tolerance of pemetrexed treatment in non-dominant population in the real world, providing a new therapeutic possibility for those who failed to be enrolled in clinical studies.