Eltrombopag Use in Patients With Chronic Myelomonocytic Leukemia (CMML): A Cautionary Tale

Eltrombopag used for thrombocytopenia in myelodysplastic syndrome (MDS) patients is being explored in clinical trials including those with chronic myelomonocytic leukemia (CMML).

We report our experience treating patients with CMML enrolled in a sequential 2-stage dose escalation study with eltrombopag in patients with MDS after hypomethylating agent failure. Patients with CMML were compared with patients with MDS in respect to response and adverse events.

Among 33 patients in the study, we treated 7 patients with CMML. Hematological improvement or better (by International Working Group 2006 criteria) was observed in 6 (23%) of 26 MDS patients and 1 (14%) of 7 patients with CMML. The responding patient with CMML had bilineage response. Two patients with CMML became platelet transfusion-independent. Five (71%) patients with CMML developed leukocytosis compared with 3 (12%) patients with MDS. Four (57%) patients with CMML showed peripheral myeloblasts after treatment compared with 11 (42%) in the MDS group. One (14%) patient with CMML developed grade 3 fibrosis from grade 0 to 1 at baseline compared with 3 (12%) patients with MDS. The rate of acute myeloid leukemia transformation was 39% and 29%, respectively, in patients with MDS and CMML.

Further clinical studies are needed to identify patients with CMML who will benefit from this treatment.