[The efficacy of treatment with native lymphoblast alpha-interferon (Wellferon) in patients with chronic myeloleukemia]. 
Data are submitted on treatment with vellferon of patients with chronic myeloid leukemia (CML) in the chronic phase of the illness.  The data obtained suggest that vellferon has a pronounced therapeutic effect in CML patients.  The drug has a positive effect on both the clinical- and hematological status and cytogenetic changes in bone marrow cells.  After 3-month treatment of patients with vellferon the sizes of the liver and spleen returned to normal as did the peripheral blood leucocyte and platelet counts.  Two patients revealed a minimum cytogenetic response to therapy, one patient achieved a complete cytogenetic remission, and only 1 patient failed to demonstrate a cytogenetic response.  A six-month therapy was associated with a complete clinical-and-hematological remission in 4 (80%) patients, with its duration ranging between 4 to 5 months, all patients maintaining a minimum cytogenetic response to vellferon treatment.  Thus, treatment with vellferon permits obtaining not only a clinical and hematological but also a cytogenetical response to therapy in a major proportion of CML patients.