Pemetrexed monotherapy for chemo-naïve elderly (aged ≥80) patients with non-squamous non-small cell lung cancer: results from combined analysis of two single arm phase II studies (HANSHIN002 and 003)

Purpose: The aim of this retrospective study was to evaluate via combined analysis the efficacy and safety of pemetrexed monotherapy for chemo-naïve elderly patients aged ≥80 with non-squamous non-small cell lung cancer (NSCLC). Methods: We conducted a combined analysis from two phase II studies of pemetrexed for chemo-naïve elderly (aged ≥75) (n = 47) and performance status 2 (n = 28) patients with advanced non-squamous NSCLC. Population aged ≥80 (80+ Group) was compared to those aged 70–79 (70’s Group). Results: We analyzed a total of 66 patients (37 70s and 29 80+ Groups) after exclusion of 4 ineligible and 5 aged ≤69 patients. Overall response rate, disease control rate, median progression-free survival, and median overall survival of 70s vs. 80+ Groups were 13.5 vs. 13.8% [p = not significant (NS)], 67.6 vs. 58.6% (p = 0.608), 3.7 months vs. 4.2 months (p = 0.5588) and 18.5 vs. 13.5 months (p = 0.2621), respectively. Non-hematological and hematological toxicities ≥grade 3 of 70s vs. 80+ Groups were 24 vs. 35% (p = 0.4192) and 49 vs. 52% (p = NS), respectively. Dose reduction and/or delay due to toxicities of 70s vs. 80+ Groups was 19 vs. 28% (p = 0.7784). Febrile neutropenia and interstitial lung disease were not observed. Treatment-related death (bacterial pneumonia) was confirmed in one (3%) of 29 80+ Group patients. Conclusions: Pemetrexed monotherapy demonstrated similar efficacy and safety between aged ≥80 and aged 70–79 populations. It could be a therapeutic option in clinical practice for elderly non-squamous NSCLC patients aged ≥80 without indications of carboplatin-based combination regimens or docetaxel monotherapy.