Alimta (pemetrexed disodium): a multitargeted antifolate for the treatment of mesothelioma

Pemetrexed disodium is an antimetabolite with multiple sites of action. It inhibits dihydrofolate reductase, thymidylate synthase, and glycinamide ribonucleotide formyl transferase (GARFT). As a single agent it is active against a variety of solid tumors. One phase II trial demonstrated a 14.5% response rate for single-agent pemetrexed disodium in patients with previously untreated mesothelioma. The combination of pemetrexed disodium and cisplatin was associated with very encouraging regression rates in mesothelioma patients treated as part of a phase I trial. A subsequent trial showed similarly encouraging activity (10 partial responses out of 25 evaluable patients [40%]) in mesothelioma patients treated with pemetrexed and carboplatin. A large, prospectively randomized, phase III trial of cisplatin alone versus cisplatin and pemetrexed with vitamin support has been completed. The findings will be presented at the 38th Annual Meeting of the American Society of Clinical Oncology in May 2002.