Single-agent ifosfamide studies in sarcomas of soft tissue and bone: the M.D. Anderson experience

We have used ifosfamide to treat patients with sarcomas in four completed single-agent protocols and one pilot study since 1985. All the studies have used either N-acetyl-L-cysteine (NAC) or mesna as a uroprotective agent, except in one arm of one study where hydration alone was employed. Mesna has proven superior to NAC in providing protection against ifosfamide-induced hematuria. Mesna given as a loading dose followed by continuous 24-h infusion has been effective and most practical in this regard. Ifosfamide has demonstrated clinically useful antitumor activity in our hands against most sarcoma subtypes. Our studies suggest a dose-response relationship for ifosfamide. At a total dose of 6 g/m2 per course, the overall response rate was 10%; at 10 g/m2 per course, it rose to 21%. Future clinical trials will determine ifosfamide's role in combination chemotherapy and more clearly define the best schedule or schedules for the uroprotective administration of mesna.