Ruxolitinib Re-Treatment in Patients with Myelofibrosis: Real-World Evidence on Patient Characteristics and Outcomes

Ruxolitinib is an FDA-approved treatment of intermediate- and high-risk myelofibrosis. In the phase 3 COMFORT studies, ruxolitinib reduced spleen volume in patients with myelofibrosis, with a median time to response of 3 months. However, nearly 20% of patients discontinued by month 4 with few treatment options available following discontinuation of ruxolitinib treatment. In this study, 2 independent patient care data sources were queried (Cardinal Health Oncology Provider Extended Network [OPEN] and HealthCore Integrated Research Environment [HIRE®]), and a retrospective review of medical charts was conducted. Patients aged ≥18 years with a diagnosis of myelofibrosis (primary or secondary), use of ruxolitinib for myelofibrosis, and documented physician-directed ruxolitinib interruption were included. Among 26 included patients, pre-interruption median (interquartile range [IQR]) ruxolitinib treatment duration was 123 (57-391, OPEN) and 110 (37-148, HIRE) days. Half the patients interrupted treatment within 3 months, commonly for adverse events (42% and 71%, respectively). After restarting ruxolitinib, median (IQR) re-treatment duration was 196 (54-553) and 166 (108-262) days, respectively. Consistent with previous reports, symptoms and spleen size improved in (OPEN/HIRE) 45%/43% and 40%/33% of evaluable patients, respectively. Further studies investigating the management of dose modifications and interruptions are needed to optimize benefit from ruxolitinib therapy.