JAK Inhibitors Demonstrate Improved Efficacy but Worse Toxicity in Myelofibrosis
Key Takeaways:
- Researchers compared Janus kinase (JAK) inhibitors against traditional therapies by analyzing 8 randomized clinical trials and 1917 patients with myelofibrosis (MF). The primary outcomes included splenic volume reduction and hematological events.
- Splenic volume reduction was greater among patients receiving JAK inhibitors. This group had more reports of splenic volume reductions of 35% or higher than those who received traditional treatments.
- Adverse events such as anemia and thrombocytopenia were more common among patients receiving JAK inhibitors than those receiving traditional therapies.
Researchers conducted a systematic search of randomized clinical trials to compare the safety and efficacy of JAK inhibitors against traditional therapies for MF.
The study assessed 8 randomized clinical trials involving 1917 patients with MS. Efficacy was measured by splenic volume reduction. Safety was evaluated based on hematological events like anemia and thrombocytopenia.
Among the 1917 patients, 1233 (62%) received JAK inhibitors and 682 (36%) received traditional therapies, including hydroxyurea and hematopoietic stem cell transplant.
Patients who received JAK inhibitors were more likely to achieve a splenic volume reduction of 35% or higher than those who received traditional treatments.
Patients who received JAK inhibitors had higher rates of adverse events such as anemia and thrombocytopenia, although incidences of thrombocytopenia were not found to be statistically significant.
According to the researchers, “Overall, this meta-analysis shows that JAK inhibitors have higher efficacy in reducing the splenic volume as compared to traditional therapies. However, JAK inhibitors are associated with more hematological side effects, specifically Anemia and thrombocytopenia.”
The data from this study highlights the importance of considering both effectiveness and toxicity when determining treatment for patients with MF and illustrates the balance physicians must strike in order to maintain quality of life.
Reference
Saqib M, Ijaz H, Zubair MM, et al. JAK inhibitors vs traditional therapy for myelofibrosis; A meta-analysis of randomized clinical trials. J Clin Oncol. 2026; 44(16):e18603. doi:10.1200/JCO.2026.44.16_suppl.e18603
