FDA Drug Approval Summaries: Pemetrexed (Alimta®)

Learning Objectives After completing this course, the reader will be able to: Explain the mechanism of action of a recently approved new cancer drug, pemetrexed. Describe the adverse-event profile of pemetrexed and a novel approach for toxicity reduction. Discuss the rationale for the FDA approval of pemetrexed. Access and take the CME test online and receive 1 hour of AMA PRA category 1 credit at CME.TheOncologist.com The purpose of this report is to summarize information on pemetrexed (LY231514; MTA; Alimta®; Eli Lilly and Company; Indianapolis, IN), a drug recently approved by the U.S. Food and Drug Administration (FDA). The review of the efficacy and safety of pemetrexed is summarized below. Pemetrexed is a pyrrolopyrimidine antifolate. It inhibits thymidylate synthase, glycinamide ribonucleotide formyltransferase, and dihydrofolate reductase. In a single, randomized, single-blind, multicenter phase III trial, the efficacy and safety of pemetrexed combined with cisplatin (Platinol®; Bristol-Myers Squibb; Princeton, NJ) were compared with those of single-agent cisplatin in 448 patients with malignant pleural mesothelioma. Two hundred twenty-six patients were randomized to receive pemetrexed and cisplatin, while 222 patients were randomized to receive cisplatin alone. The primary study end point was survival. Median survival times were 12.1 months for the pemetrexed plus cisplatin treated arm and 9.3 months for the cisplatin alone arm. Pemetrexed causes myelosuppression. The most common adverse events were neutropenia, fatigue, leukopenia, nausea, dyspnea, and vomiting. On February 4, 2004, pemetrexed was approved by the FDA in combination with cisplatin for the treatment of patients with malignant pleural mesothelioma whose disease is unresectable or who are otherwise not candidates for curative surgery. The recommended dose of pemetrexed is 500 mg/m2 administered as an i.v. infusion over 10 minutes on day 1 of each 21-day cycle together with cisplatin at a dose of 75 mg/m2 infused over 2 hours beginning 30 minutes after the pemetrexed infusion. Patients must receive oral folic acid and vitamin B12 injections prior to the start of therapy and continue these during therapy to reduce severe toxicities. Patients should also receive corticosteroids with chemotherapy to reduce the risk of skin rashes. Approval was based on superior survival as a clinical benefit.