Survival outcomes of alternate dosing schedule of pemetrexed as maintenance therapy in NSCLC: Single institution experience

Background: Maintenance therapy with pemetrexed has shown survival benefit in patients with advanced stage non-small cell lung cancer (NSCLC). The recommended dose schedule is 500 mg/m 2 in 21-day cycles. Prolonged treatment with maintenance pemetrexed can result in cumulative toxicities. We sought to compare treatment outcomes in patients receiving an alternate maintenance schedule in realworld practice. Methods: This single-center, retrospective study investigated patients with advanced stage (IIIB and IV) NSCLC receiving at least two doses of maintenance pemetrexed from May 1, 2011 to June 30, 2016. The objective was to compare time on treatment with maintenance pemetrexed therapy initiated at a standard schedule (q3 weeks) versus an alternate schedule (q4 weeks or longer). Also evaluated were progressionfree survival (PFS) and overall survival (OS) differences between the two groups. Results: 129 patients were included, of whom 40 started the alternate schedule no later than cycle 3 of treatment (29 of 40 patients initiated maintenance treatment on the alternate schedule). Average time on maintenance treatment for patients appeared to be longer in the patients who received the alternate schedule regimen (195 vs 263 days, p=0.008). OS trended towards better survival among patients receiving the alternate schedule regimen (11.9 vs 18.1 months, p=0.3). Limiting the analysis to ALK wildtype, the patients showed a similar trend, with median PFS (7.6 vs 11.5 months, p=0.46) and OS (11.9 vs 17.6 months, p=0.38), still favoring the alternate schedule. Conclusions: The alternate dosing schedule of maintenance pemetrexed (q4 weeks or longer) is feasible and not detrimental to OS. Future investigations evaluating the optimal administration schedule of maintenance pemetrexed is warranted.

Automated summary

This study compared treatment outcomes between patients receiving maintenance pemetrexed therapy on a standard schedule and an alternate schedule. The results showed that patients on the alternate schedule had a longer time on maintenance treatment and trended towards better overall survival.