The researchers found that the mean changes in hematologic indices from cycle 1 (C1) to C2 or C2 to C3 did not differ significantly between the 2 groups. In addition, they found no significant differences in clinical events between C1 and C2 or C2 and C3 where supportive care was required.

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The study showed that treatment delays in C3 occurred in 24.6% of the patients in the same-day group compared with 11.9% in the prior group. The most common significant predictors of delay in C3 in the same-day group were baseline hemoglobin and absolute neutrophil count. Another common reason for delay in C3 was patient preference (vacation, schedule conflicts, holidays) rather than medically related.

“Our findings indicate that among patients in the United States, pemetrexed can safely be administered on the same day as vitamin B12 administration. A 7-day interval from vitamin B12 administration to chemotherapy administration is not necessary,” Dr Dy told Oncology Nurse Advisor.

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Overall, the researchers concluded that clinically meaningful changes in hematologic indices did not differ between patients based on the lead-in time of vitamin B12 supplementation. However, the authors caution that there are inherent limitations to these findings due to this being a single-center retrospective study.


This study demonstrated that same-day administration of vitamin B12 may facilitate earlier initiation of treatment, which may be clinically relevant. The authors note that clinical trials with pemetrexed currently stipulate administration of vitamin B12 at least 7 days before pemetrexed infusion. Based on these new findings, Dr Dy and colleagues recommend same-day vitamin B12 supplementation as a standard option in clinical trials utilizing pemetrexed, contending that this will help reduce unnecessary treatment delays.

Dr Dy said these results were slightly different from the findings of a randomized study conducted in India, which showed higher rates of thrombocytopenia in patients receiving same-day supplementation. However, those findings may be a reflection of regional or geographic variation in diet as well as routine folate fortification in grain products here in the United States.


Schlei Z, Tan W, Faber MG, Chen H, Meagher A, Dy GK. Safety of same-day vitamin B12 supplementation in patients receiving pemetrexed for the treatment of non–small-cell lung cancer or pleural mesothelioma: a retrospective analysis. Clin Lung Cancer. 2018;19(6):467-475.

This article originally appeared on ONA