The Sarawak Myelofibrosis (SaMy) experience: Demographics and outcome of myelofibrosis patients in Sarawak, Malaysia

Introduction: Myelofibrosis is a rare disease. There is currently no published data reporting the demographics and outcome of myelofibrosis patients in Malaysia. We aimed to study the demographics, clinical characteristics, and outcome of our patients in Sarawak. Materials and methods: This non-interventional, retrospective, and multicenter study was conducted on secondary data of medical records collected at four Sarawak Public Hospitals. All adult myelofibrosis patients diagnosed between January 2001 and December 2021 were included. Results: A total of 63 patients (male 31) with myelofibrosis were included-47 (74.6%) primary and 16 (25.4%) secondary myelofibrosis. Eleven had antecedent polycythaemia vera, whereas five transformed from essential thrombocythaemia. The combined annual incidence rate was 0.182 per 100,000 population. The period prevalence per 100,000 population over the entire study duration was 2.502. The median age was 59.0 years (33.0-93.0). Majority had high-risk (34/ 63(54.0%)) and intermediate-2 risk disease ( 19/63(30.2%)). JAK2V617F mutation was identified in 52 patients (82.5%), followed by CALR mutation in 6 (9.5%) and negative for both mutations in 5 ( 7.9%). Hydroxyurea was used as first- line therapy in 41/ 63 (65.1%), followed by interferon (8/63(12.7%)) and ruxolitinib (4/ 63(6.3%)). Out of 46 patients who received second- line therapy, 18 ( 39.1%) were switched to ruxolitinib and 9 ( 19.6%) to interferon. The median age of survival for overall patients was 6.8 years. The use of ruxolitinib in myelofibrosis patients showed a better overall 5- year survival compared to the no ruxolitinib arm, despite no statistical significance (p = 0.34). Patients who had good performance status had lower hazard of death than patients who had poor performance status (high- risk (95% confidence intervals): 0.06(0.013-0.239), p < 0.001). Patients with intermediate risk disease had better overall survival compared to those in high-risk group (95% confidence intervals): 0.24(0.082-0.695), p = 0.009). Conclusion: This registry provides a realworld overview of myelofibrosis patients in our state and highlights the key insight into the unmet clinical need.