Disease characteristics and response to treatment of patients with myelofibrosis: a multicentre descriptive, retrospective study from Sri Lanka

Introduction and objectives: Myelofibrosis (MF) is a BCR/ABL negative, myeloproliferative neoplasm. The manifestations of MF include constitutional symptoms, splenomegaly, anaemia and other cytopenias. Most of the patients are elderly with multiple comorbidities and cannot undergo allogeneic stem cell transplantation. Hence treatment is mainly aimed at controlling symptoms and complications. Given the varying clinical needs of these patients, and the wide array of therapeutic options available, it is challenging to choose the best therapeutic agent for each patient. The main objective of this multicentre study, the first of this nature for MF in Sri Lanka, was to describe clinical and laboratory characteristics of patients and to assess various treatment modalities practiced in the country.

Method: Following informed written consent, data was gathered from 28 units covering 9 provinces in the country. Analysis was using SPSS software.

Results: Of the 104 patients with MF, 87 were primary, 16 post polycythaemia vera and one post essential thrombocythemia. Median age 58.9 years and male : female ratio 51:49. The main presenting features were splenomegaly 78.8%, constitutional symptoms 63.5% and anaemia 59.6%. Leukocyte count >25x10⁹/L, blasts in the peripheral blood and platelets <100x10⁹/L were seen in 23.1%, 18.3 and 17.3%. JAK 2 V617F mutation was checked only in 77 patients due to lack of facilities and 61% were positive. 62 patients required RBC transfusions, 32 patients received erythropoietin therapy, 19 thalidomide/ prednisolone and 7 received only thalidomide. Positive responses were seen in 53.1%, 52.6% and 42.9% respectively. Splenomegaly was seen in 82 patients. 67 received hydroxyurea, 13 ruxolitinib, 10 thalidomide/ prednisolone and 10 thalidomide only. Positive responses were 80.6%, 61.5%, 50% and 50% respectively. Constitutional symptoms were treated with ruxolitinib in 14 patients. 92.9% showed a positive improvement.

Conclusions: Hydroxyurea, is the most commonly used, least expensive and the most effective treatment option for splenomegaly. Thalidomide/ prednisolone and thalidomide alone have shown similar positive responses when used against splenomegaly but the patient number is small and should be further analysed with a larger study population. Out of the treatment options used for anaemia, more than 50% of positive responses were seen with erythropoietin and thalidomide/ prednisolone. Ruxolitinib though used only in 14 patients, had shown a good response in controlling constitutional symptoms and splenomegaly, but the use of the drug was limited by high cost and anaemia.