Introduction Oral folic acid supplementation is essential for patients treated with pemetrexed, to prevent the risk of severe hematologic toxicity. In case of intestinal absorption disorder, no recommendations exist for intravenous folic acid supplementation. Case report We describe a 74-year-old patient with multimetastatic non-small-cell lung adenocarcinoma, receiving first-line chemotherapy with carboplatin AUC5, pemetrexed 500 mg/m2 and pembrolizumab 200 mg intravenously every 3 weeks. The patient presented neglected celiac disease, resulting in malabsorption syndrome with iron and folic acid deficiency. The question was how to administer folic acid supplementation during the pemetrexed-based chemotherapy. Management and outcomes Intravenous injection of 200 mg levoleucovorin on day 1 of cycle 1 of pemetrexed-based chemotherapy was administered and well tolerated. During the second cycle, the levoleucovorin perfusion was not renewed by omission. The patient was hospitalized for 7 days because of febrile aplasia. Piperacillin–tazobactam was started, and then switched to amoxicillin–clavulanate plus ciprofloxacin. After this episode of post-chemotherapy febrile aplasia, it was decided to systematically supplement the patient with intravenous levoleucovorin, with blood folate concentration monitoring at each cycle. At 16 months after start of treatment, the patient was in complete remission, indicating that the immune-chemotherapy was effective, with no further febrile neutropenia. Discussion/conclusion This case report highlights intravenous levoleucovorin supplementation as an alternative to oral folic acid if needed during pemetrexed–antifolate-based chemotherapy.
