Suzhou Zelgen Biopharmaceuticals Co., Ltd (SHA: 688266) has published major data from a Phase III clinical study for its Janus kinase (JAK) inhibitor, jacktinib, in patients with medium- to high-risk myelofibrosis (MF). The results indicate an excellent efficacy and safety profile for the drug. A New Drug Application (NDA) for jacktinib for this indication was accepted for review by the National Medical Products Administration (NMPA) last week.
Phase III Study Results
The randomized, double-blind, double-dummy, parallel controlled, multi-center Phase III study assessed the efficacy and safety of jacktinib compared with hydroxycarbamide (hydroxyurea) in medium- to high-risk MF. The study enrolled 105 subjects and reached the primary efficacy endpoint as reviewed by the Independent Data Monitoring Committee (IDMC). The proportion of subjects whose spleen volume decreased by ≥ 35% from baseline at 24 weeks (main efficacy result SVR35) was 72.3% in the jacktinib 100mg Bid group and 17.4% in the hydroxycarbamide 0.5g Bid group (P<0.0001). Additional indicators, including clinical improvement, anemia response, hemoglobin improvement, disease symptom score, and spleen response, showed that jacktinib outperformed hydroxycarbamide.
Safety Profile
In terms of safety, jacktinib was found to be safe and well-tolerated. The overall incidence of drug-related adverse reactions (ADRs), ADRs ≥ 3, drug-related serious adverse events (SAE), ADRs leading to dose reduction or suspension, ADRs leading to permanent discontinuation, and the incidence of drug-related adverse events of special interest (AESI) were all lower in the jacktinib group compared to hydroxycarbamide.
Mechanism and Development Pipeline
Jacktinib works by blocking the signal transducer and activator of transcription (STAT) and JAK signaling pathways, thereby improving immune-related inflammatory effects. The drug is currently undergoing multiple clinical studies in various indications, including moderate- to high-risk myelofibrosis, myelofibrosis intolerant to ruxolitinib, severe alopecia areata, idiopathic pulmonary fibrosis, ankylosing spondylitis, moderate to severe plaque psoriasis, and moderate to severe atopic dermatitis. Jacktinib has obtained orphan drug designation status for myelofibrosis from the US FDA. In China, the drug received Phase II clinical study approval for use in severe COVID-19. Additionally, a Phase II clinical study in active ankylosing spondylitis (AS) was recently concluded successfully.
Future Outlook
The positive Phase III results for jacktinib in myelofibrosis highlight Zelgen’s progress in developing targeted therapies for rare and challenging diseases. With multiple ongoing clinical studies and regulatory milestones achieved, Zelgen aims to expand the therapeutic options for patients with significant unmet medical needs.-Fineline Info & Tech
