Dr. Jie Jin
Honorary Director, Department of Hematology, the First Affiliated Hospital of Zhejiang University School of Medicine
The 28th European Hematology Association (EHA) Congress was held from June 8th to June 11th, 2023, in Frankfurt, Germany, in a hybrid format combining online and offline meetings. As the largest international conference in the field of European hematology, the EHA Congress covered a wide range of scientific topics, clinical and basic research, including both benign and malignant hematology, discussing the latest developments in the field. Regarding the treatment of Myelofibrosis (MF), several studies from Dr. Jie Jin’s team at the First Affiliated Hospital of Zhejiang University (abstracts S212, P1201, and P1033) were selected for this congress. These studies focused on exploring the efficacy and safety of the new JAK inhibitor Jaktinib in the treatment of MF, attracting significant attention due to its clinical significance. In this regard, Oncology Frontier conducted an on-site interview with Professor Jin Jie and provided a brief explanation of this topic.
Oncology Frontier: Please briefly introduce the current main treatment methods for Myelofibrosis (MF) and the unmet clinical needs.
Dr. Jie Jin: Myelofibrosis (MF) is a type of myeloproliferative neoplasm (MPN), and compared to essential thrombocythemia (ET) and polycythemia vera (PV), MF generally has a worse prognosis. According to the International Prognostic Scoring System (IPSS) and the Dynamic International Prognostic Scoring System (DIPSS), MF can be roughly classified into low-risk, intermediate-risk (intermediate-1 and intermediate-2), and high-risk groups. Currently, the treatment mainly targets patients in the intermediate-2 and high-risk groups. The recommended treatment drugs in the guidelines primarily include ruxolitinib and hydroxyurea. However, it’s worth noting that the treatment with ruxolitinib or hydroxyurea only addresses some of the symptoms related to splenomegaly, constitutional symptoms, and burdens in a subset of MF patients. Many patients still do not experience improvement in these symptoms. Additionally, ruxolitinib treatment can lead to adverse events such as anemia, cytopenias, and infections. Hydroxyurea has relatively better safety, but its effectiveness in reducing spleen size and improving constitutional symptoms is relatively modest.
Oncology Frontier: Your team’s oral presentation (S212) compared Jaktinib vs. hydroxyurea in the efficacy for intermediate-2 or high-risk MF patients. Could you please provide a detailed interpretation of this study?
Dr. Jie Jin: This study was a randomized, double-blind Phase III clinical trial that compared the efficacy of the novel JAK inhibitor Jaktinib with hydroxyurea in intermediate-2 or high-risk MF patients. A total of 105 patients were enrolled in the study, and according to the protocol, a midterm analysis was performed based on data from the first 70 randomized subjects who completed 24 weeks of treatment follow-up. The primary endpoint was the proportion of patients with a ≥35% reduction in spleen volume from baseline at 24 weeks, as assessed by central imaging. The results showed that:
1. Jaktinib achieved a 72.3% SVR35 (spleen volume reduction ≥35%) at 24 weeks, significantly higher than the 17.4% in the control group (hydroxyurea group), demonstrating a markedly superior efficacy.
2. Within 24 weeks, Jaktinib showed better outcomes in terms of anemia response, improvement in hemoglobin levels, MPN-SAF TSS symptom scores, and spleen response compared to hydroxyurea.
3. In terms of safety, the rates of common ≥Grade 3 treatment-emergent hematologic adverse events (TEAEs) and common non-hematologic TEAEs were lower in the Jaktinib group compared to the hydroxyurea group.
Oncology Frontier:Could you discuss the differences in efficacy and safety between Jaktinib and ruxolitinib in the treatment of MF?
Dr. Jie Jin: Although there have been no head-to-head studies comparing Jaktinib and ruxolitinib in the treatment of MF, based on the results from our center’s participation in a previous Phase II clinical trial of ruxolitinib, the proportion of patients achieving SVR35 at 24 weeks, as assessed by central imaging, was lower than the data reported in this study for the Jaktinib group. Additionally, the incidence of anemia during ruxolitinib treatment reached 42%, which is significantly higher than with Jaktinib. However, it’s important to note that results from head-to-head studies would provide more robust evidence on this matter.
