Efficacy, safety, and survival findings after long‐term follow‐up of ZGJAK002: A phase 2 study comparing jaktinib at 100 mg twice daily (BID) and 200 mg once daily (QD) in patients with myelofibrosis

Abstract

Myelofibrosis (MF) is a Philadelphia-negative myeloproliferative neoplasm (MPN) characterized by bone marrow fibrosis, anemia, splenomegaly, constitutional symptoms, leukemia transformation, and reduced survival. Currently, Janus kinase inhibitors (JAKi) still the recommended first-line treatment for intermediate-and high-risk myelofibrosis. Jaktinib, a deuterated form of momelotinib, 1,2 is a JAK (JAK1, JAK2, JAK3, and TYK2) and ACVR1 inhibitor. It has exhibited promising results in treating patients with MF. Patients treated with jaktinib have shown spleen reduction, symptom relief, and improvement in anemia in both JAKi-naïve (ZGJAK002, 3 ZGJAK016 4 ) and ruxolitinib-intolerant (ZGJAK006 5 ) or -resistant (ZGJAK017 6 ) clinical trials. The ZGJAK002 study is a phase 2 trial aimed at assessing the efficacy and safety of jaktinib at doses of 100 mg BID and 200 mg QD in JAKi-naïve patients with intermediate-or high-risk MF per DIPSS-plus criteria. The primary endpoint was the proportion of patients with ≥35% reduction in spleen volume (SVR35) at week 24. The secondary endpoints included symptom response (TSS50, MPN-SAF TSS decreased by ≥50%), improvement of anemia, and safety profile. The initial findings from this study indicate that jaktinib promptly reduces spleen size, enhances symptoms, and alleviates anemia in patients.