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.