US Food and Drug Administration drug approval summaries: Imatinib mesylate, mesna tablets, and zoledronic acid

The purpose of this report is to summarize information on drugs recently approved by the U.S. Food and Drug Administration. Three drugs have recently been approved: Gleevec(TM) (imatinib mesylate) at a starting dose of 400 or 600 mg daily for the treatment of malignant unresectable and/or metastatic gastrointestinal stromal tumors; Mesnex(R) (mesna) tablets as a prophylactic agent to reduce the incidence of ifosfamide-induced hemorrhagic cystitis, and Zometa(R) (zoledronic acid) for the treatment of patients with multiple myeloma and for patients with documented bone metastases from solid tumors, in conjunction with standard antineoplastic therapy. Prostate cancer should have progressed after treatment with at least one hormonal therapy. The recommended dose and schedule is 4 mg infused over 15 minutes every 3-4 weeks. These three drugs represent three different types of drug approval: Gleevec is an accelerated approval and supplemental new drug application (NDA); Mesnex tablets represent an oral formulation of a drug approved 14 years ago as an intravenous formulation, and Zometa represents a standard NDA for a noncytotoxic, supportive-care drug. Information provided includes rationale for drug development, study design, efficacy and safety results, and pertinent literature references.