Phase II study of pentostatin and intermittent high-dose recombinant interferon alfa-2a in advanced mycosis fungoides/Sézary syndrome.

Purpose: This phase II study was undertaken to assess the efficacy and toxicity of alternating administration of pentostatin (deoxycoformycin [DCF]) and interferon alfa-2a (IFN) in patients with advanced or refractory mycosis fungoides (MF) or the Sézary syndrome (SS).

Patients And Methods: Forty-one patients underwent therapy with alternating cycles of DCF 4 mg/m2 intravenously (IV) days 1 through 3 and IFN 10 million U/m2 intramuscularly (IM) day 22, and 50 million U/m2 intramuscularly (IM) days 23 through 26. Twenty-nine patients had not responded to prior chemotherapy or total-skin electron-beam irradiation (TSEB), six had not responded to topical therapies, and six had no previous treatment.

Results: Two patients achieved a complete response (CR) and 15 achieved a partial response (PR), for an overall response rate of 41% (95% confidence interval, 26% to 58%). No responses were observed in the seven patients with visceral involvement. The median progression-free survival of patients who responded was 13.1 months. IFN-related constitutional symptoms were reported in 39% of patients; severe toxicities included cardiomyopathy in one patient, acute and chronic pulmonary dysfunction in four, and reversible mental status changes in two. Seven patients developed herpes zoster during therapy and six had staphylococcal bacteremia.

Conclusion: These results suggest that the combination of DCF and IFN is an active regimen in MF patients without visceral involvement.