Elderly subset analysis of randomized phase III study comparing pemetrexed plus carboplatin with docetaxel plus carboplatin as first-line treatment for patients with locally advanced or metastatic non-small cell lung cancer.

Background: Many physicians consider platinum-doublet chemotherapy inappropriate for elderly patients, regardless of their medical fitness.

Objective: This was a retrospective subgroup analysis of data from a multicenter, randomized, phase III clinical trial evaluating pemetrexed + carboplatin versus docetaxel + carboplatin in elderly chemo-naive patients with advanced, nonsquamous non-small cell lung cancer (NSCLC).

Methods: Data from elderly patients (aged ≥65 years and ≥70 years) were evaluated using the same statistical methods as those used in patients aged <70 years and qualified intent-to-treat (Q-ITT) populations. The primary objective of the clinical trial was comparison of pemetrexed + carboplatin with docetaxel + carboplatin in terms of survival without grade 3 or 4 toxicity in chemo-naive NSCLC patients.

Results: The ≥65- and ≥70-year age groups had 68 and 37 patients, respectively. Among patients aged ≥65 years, the adjusted hazard ratio (HR) for survival without grade 3-4 toxicity (HR 0.40, 95 % confidence interval [CI] 0.23-0.70) favored pemetrexed + carboplatin; this was similar to the HRs in patients aged ≥70 years (HR 0.43, 95 % CI 0.20-0.92), patients aged <70 years (HR 0.44, 95 % CI 0.32-0.62), and the Q-ITT population (HR 0.45, 95 % CI 0.34-0.61). The median values for overall survival (OS) and progression-free survival (PFS) were similar across all age-group subsets and the Q-ITT population. The HRs for OS and PFS were similar for all age-group subsets, except for the ≥70-year age group, which favored pemetrexed + carboplatin to a greater extent. The toxicity profile was similar across age groups, with the exception of diarrhea, mucosal inflammation, and grade 3-4 neutropenia and leukopenia, which were slightly more common in elderly patients in both treatment arms. Between-arm differences in the toxicity profiles for the ≥65-, ≥70- and <70-year age subgroups were similar to those in the Q-ITT population. There were no on-study deaths or unexpected toxicities.

Conclusion: The benefits of pemetrexed + carboplatin were maintained, and toxicity was manageable in both elderly subgroups. The favorable risk-benefit profile of pemetrexed + carboplatin makes it an appropriate first-line treatment option for elderly patients with advanced nonsquamous NSCLC.