Abnormal elevation of erythrocyte mean corpuscular volume (MCV) in non-small cell lung cancer (NSCLC) patients treated with maintenance pemetrexed-based chemotherapy.

e17564 Background: Pemetrexed (Pem) is commonly used as frontline +/- maintenance chemotherapy (MCTx) in patients (pts) with advanced non-squamous (ns) NSCLC. Due to Pem toxicity profile, pts can remain on therapy (tx) for prolonged periods of time. We are reporting an increase in the erythrocyte MCV without apparent clinical significance. Methods: 54 ns-NSCLC pts previously treated with Pem-based tx either as initial treatment followed by MCTx Pem alone or Pem/bevacizumab (Bev) or second line tx were analyzed for elevation of MCV from a normal baseline (80-98 fl). All pts were on daily folic acid (FA) and vitamin B12 (vitB12) supplementation at least every 3 cycles of Pem. Co-factors such as FA, vitB12, homocysteine (Hom), and methylmalonic acid (MMA) were measured on those pts still alive, on active MCTx, and available who had high MCV. Results: 54 pts were evaluable; 50 pts received platinum/Pem/Bev triplet as initial tx followed by Pem/Bev or Pem MCTx and 2 pts with Pem/Bev and Pem alone as second lin...