Background: During therapy with tyrosine kinase inhibitors (TKIs), approximately 20% to 50% of patients with chronic myeloid leukemia (CML) develop grade >or=3 thrombocytopenia leading to treatment interruptions and dose reductions. Interleukin 11 (IL-11) reduces the incidence and the severity of thrombocytopenia in solid tumors.
Methods: The authors investigated the efficacy and safety of low-dose IL-11 for improving thrombocytopenia associated with TKI therapy in 14 patients with CML. The starting dose of IL-11 was 10 microg/kg 3 times weekly, and the dose was escalated by 1 dose level every 2 weeks if the patients had no sustained platelet increase.
Results: The median patient age was 52 years. The median platelet count at the time IL-11 was started was 37 x 10(9)/L. All patients had prior TKI dose reductions. After the initiation of IL-11, 8 of 14 patients (57%) had an increase in platelet count with a median peak platelet count of 110 x 10(9)/L. One additional patient had no platelet increase but was able to tolerate an imatinib dose increase. Eleven patients had a decrease in the number of days of TKI therapy interruption secondary to thrombocytopenia after the initiation of IL-11 (6% of total treatment time vs 34% of total treatment time before IL-11). Therapy was well tolerated.
Conclusions: The current results indicated that IL-11 may correct thrombocytopenia associated with TKI therapy for patients with CML and that it has a favorable toxicity profile.
(c) 2008 American Cancer Society.