Clinicians now have a better understanding of the ideal time in which to give vitamin B12 supplementation to patients receiving pemetrexed for the treatment of non-small cell lung cancer (NSCLC) or pleural mesothelioma. A new study published in the journal Clinical Lung Cancer has found that administering both vitamin B12 and pemetrexed on the same day appears to be a safe practice.
“We did this analysis to resolve the practical question on the optimal timing of administering vitamin B12 and folate supplementation prior to starting pemetrexed. This was an area of some controversy,” explained study investigator Grace Dy, MD, division chief of Thoracic Oncology and associate professor of oncology in the Department of Medicine at Roswell Park Comprehensive Cancer Center, in Buffalo, New York. “Many clinical trials still require a 7-day wait time between vitamin B12 supplementation and administering pemetrexed, resulting in an extra week of delay in start of therapy.”
Dr Dy and colleagues conducted a single-center, retrospective study in which they assessed the safety of same-day B12 supplementation vs B12 supplementation 1 or more days prior to pemetrexed infusion in patients with NSCLC or pleural mesothelioma. All the patients had new diagnoses and received pemetrexed 500 mg/m2 with or without a platinum agent (cisplatin or carboplatin). Vitamin B12 1000 mg was administered intramuscularly.
Pemetrexed is a folate analog inhibitor approved by the FDA in 2004. Currently, it is considered a first-line therapy, with or without a platinum agent, for nonsquamous NSCLC and malignant pleural mesothelioma. Folic acid and vitamin B12 supplementation are required before treatment with pemetrexed due to high rates of cytopenia without the supplementation.
Little data demonstrating optimal timing of supplementation is available. Dr Dy and colleagues analyzed safety outcomes of same-day supplementation vs supplementation 1 or more days prior to pemetrexed infusion. They identified 281 patients (mean age 64.1 years): 137 patients received same-day IM administration of B12 supplementation (same-day group) and 144 patients received IM B12 supplementation at a median 7 days (range, 1 to 42 days) prior to pemetrexed infusion (prior group).