A prospective phase II clinical trial with the use of zidovudine and interferon-alpha in the acute and lymphoma forms of adult T-cell leukemia/lymphoma

Adult T-cell leukemia/lymphoma ATL is an aggressive T cells malignancy, with poor prognosis due to chemotherapy resistance. Preliminary results using zidovudine (AZT) and interferon-α (IFN) showed high response rate in ATL patients. We report a prospective phase II trial using AZT/IFN treatment for aggressive ATL. Nineteen ATL patients (15 acute and four lymphoma) were included in this study. Thirteen patients received AZT/IFN as initial treatment and six patients after initial chemotherapy. For the 17 patients with evaluable tumor, 13 responses were obtained with nine complete remissions (CR) and four partial remissions (PR). Response rate (RR) was 92% for patients who received AZT/IFN as initial treatment (58% CR and 33% PR). Toxicity was mild, mainly hematological. One patient died of fulminant viral hepatitis. Fifteen patients relapsed with a median event free survival (EFS) of seven months for the whole population (range 1-50+ months), 10 months for patients who received AZT/IFN as initial therapy and two months for patients who received initial chemotherapy. Median overall survival (OS) was 11 months for the whole population (range 1-82+ months) and 28 months for patients who entered CR. Three acute ATL showed prolonged CR (42, 52+ and 84+ months respectively) on maintenance therapy with AZT/IFN. This study confirms the efficacy and safety of AZT/IFN in ATL with high response and CR rates. Despite impressive prolonged CR of more than three years, most of the patients relapse stressing the need for additional therapy after achieving CR with AZT/IFN.