Intermittent Low Dose Interleukin 11 Can Lead to Transfusion Independence in Patients with Chronic Myelo-Monocytic Leukemia and Thrombocytopenia.

Recombinant Interleukin- 11 (IL-11) is a thrombopoietic cytokine that stimulates megakaryocytopoiesis in vitro and platelet production in vivo. It attenuates post chemotherapy thrombocytopenia at a dose of 50 mcg/ kg/ day subcutaneously (SC). Unfortunately, prolonged administration is associated with significant toxicity including peripheral and pulmonary edema at this dose. Administration of low dose IL-11 at 10 mcg/kg/day SC has shown efficacy in bone marrow failure states without significant toxicity. We report two cases of chronic myelo-monocytic leukemia (CMML) with transfusion dependent thrombocytopenia who received intermittent low dose IL-11 without significant toxicity.

Case Reports- Patient 1 is a 79-year-old male with history of CMML with pancytopenia of three years duration. Recently he required transfusion of platelets with his platelet counts falling to less than 15 x 10⁹/L. His cytogenetic study showed normal karyotype, 46 XY. He required platelet transfusion at every 14 days. He initially was started on IL-11 at 10mcg/kg/day, 5 days per week.. His platelet count increased to above 30 x 10⁹/L and he became transfusion independent within two weeks. Unfortunately on this schedule he developed edema and mild CHF. IL-11 was stopped for two weeks and upon resolution of toxicity, restarted at 10 mcg/kg/day on Monday, Wednesday and Friday. He has remained transfusion independent without recurrence of edema at 5 months on this schedule.

Patient 2 was a 63-year-old male with previous history of chronic lymphocytic leukemia and diffuse large B cell lymphoma who developed CMML with severe pancytopenia. His karyotype was 46, XY, −7, +21. His platelet count was consistently less than 10 x 10⁹/L. He required platelet transfusion twice a week. He was started on IL-11 at 10mcg/kg/day for 5 days per week, two weeks on and two weeks off. His platelet count increased to as high as 64 x 10⁹/L after 2^nd cycle. His platelet transfusion requirement decreased from every 3^rd day to every 10^th-14^th day. He experienced no peripheral or pulmonary edema.

Conclusion: Administration of low dose IL-11 in other bone marrow failure states has been reported but its use has not been described in CMML. Our observation in these 2 patients suggests that IL-11 has efficacy in CMML and is very well tolerated at low doses on an intermittent administration schedule. IL-11 may decrease the transfusion requirement in transfusion dependent patients. Further studies are needed to evaluate overall impact on larger number of patients who require regular platelet transfusion.