Background: Chronic myelogenous leukemia is characterised by the presence of Philadelphia translocation and consecutive expression of bcr-abl oncogene with enhanced tyrosine kinase activity, which is known to be the essential pathogenetic event in the disease. Imatinib (Glivec, formerly STI571) is a highly selective inhibitor of the bcr-abl tyrosine kinase which has shown a promising therapeutic activity in chronic myeloid leukemia as the first molecularly targeted antinoplastic treatment.
Methods: Between January 2001 and October 2001, 54 patients with chronic phase CML, resistant or intolerant to interferon-alpha were enrolled into the Novartis Expanded Access Study (Protocol 0113). Patients characteristics were as follows: male/female: 32/22, median age: 49 years (range: 22-75), median duration of disease: 44 months (range: 3-152). All patients received 400 mg imatinib orally.
Results: Complete hematologic response was obtained in 53 patients (96%) within 4 weeks. Major cytogenetic response (< 35% Ph+ metaphasis) was achieved after 6 months in 62.9%, and after 12 months in 64.8% of patients. Three patients progressed during the treatment (loss of complete hematologic response or cytogenetic response 1, blastic phase 2). The treatment was well tolerated, with mild side effects. Main non-hematologic side effects were weight gain and fluid retention.
Conclusions: The results confirm that imatinib is highly active in inducing complete hematologic response and major cytogenetic response in most patients who failed interferon-alpha. Treatment was well tolerated with rare and mild adverse events and impressive improvement of quality of life.