USE OF INTERFERON-ALPHA-2A TO TREAT CYTOGENETIC RELAPSE OF CHRONIC MYELOID-LEUKEMIA AFTER MARROW TRANSPLANTATION

Fourteen patients with cytogenetic relapse of chronic myeloid leukemia (CML) after transplantation with unmanipulated bone marrow were treat ed with alpha-2a-interferon. There were eight men and six women, media n age, 33 years. Twelve patients received marrow from a related alloge neic donor and two received marrow from a syngeneic donor. The median percentage of Ph-positive metaphases at the time of starting interfero n was 55% (10% to 87%). Daily interferon was started at a dose of 1 to 3 x 10(6) U/M-2/d, depending on initial blood counts and was adjusted as tolerated to maintain the white blood count in the range of 2,000 to 3,000/mu L and the platelet count greater than 60,000/mu L. After a stable cytogenetic remission was achieved, the interferon dose was de creased to a maintenance level. Twelve patients achieved a complete cy togenetic remission on at least one occasion. Median time to achieve a complete cytogenetic remission was 7.5 months (range, 1.5 to 12). Eig ht patients remain in cytogenetic remission for 10+ to 54+ months from the time of first documented remission. After complete cytogenetic re mission was established, nine patients were tested for the presence of the mRNA transcript of the bcr/abl fusion gene by polymerase chain re action (PCR) testing. Four patients were PCR-negative on at least one occasion: two patients were PCR-negative on a single occasion; one pat ient had serial tests, which were PCR-negative; and one patient had se rial PCR-negative peripheral blood tests with a single PCR-positive bo ne marrow obtained concurrently with a negative peripheral blood test. Median follow-up time for all patients is 44 months (range, 20 to 64) . Interferon was generally well tolerated; only one responding patient was unable to continue interferon because of toxicity. Interferon ind uces durable cytogenetic remissions in a significant proportion (57%) of patients with cytogenetic relapse following bone marrow transplanta tion (BMT) without causing life-threatening toxicities. (C) 1997 by Th e American Society of Hematology.