An observational study in Myeloproliferative Neoplasms/Myelofibrosis, sponsored by Affiliated Hospital of Nantong University. Not yet recruiting at 1 site in China. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-11-09.
Sponsored by Affiliated Hospital of Nantong University · Observational
This is a multicenter, prospective, observational clinical study designed to evaluate the real-world efficacy and safety of jaktinib in patients with newly diagnosed myelofibrosis (MF). The primary outcome measure is the proportion of patients achieving anemia response at week 24. Secondary outcome measures include MF-related symptom response rate (TSS50) at week 24, spleen volume reduction ≥35% (SVR35) at week 24, progression-free survival (PFS), leukemia-free survival (LFS), overall survival (OS), and safety/tolerability. This study will provide real-world evidence supporting the use of jaktinib as a first-line treatment for newly diagnosed MF patients.
Myelofibrosis (MF) is a BCR::ABL1-negative myeloproliferative neoplasm (MPN) characterized by progressive splenomegaly, debilitating systemic symptoms, abnormal blood cell counts, and a risk of leukemic transformation. Patients often suffer from progressive anemia, thrombocytopenia, and systemic symptoms including fatigue, dyspnea, night sweats, weight loss, fever, and bone pain. Notably, the incidence of anemia at diagnosis in Chinese patients with primary myelofibrosis (PMF) is 67%, significantly higher than that observed in Western counterparts (35%), underscoring a critical unmet need for therapies that address both splenomegaly and anemia in this population.
Mutations in JAK2, CALR, or MPL genes, found in approximately 90% of patients, lead to hyperactivation of the JAK-STAT pathway, which is pivotal in the pathogenesis of MF. Advances in understanding this pathway have led to the development of JAK inhibitors, with ruxolitinib (2011), fedratinib (2019), pacritinib (2022), and momelotinib (2023) approved by the U.S. Food and Drug Administration (FDA) for the treatment of MF symptoms and splenomegaly. In China, ruxolitinib is the first JAK inhibitor approved for the treatment of MF. However, its efficacy in the Chinese population is modest, with a ≥35% spleen volume reduction (SVR35) rate of only 27% at week 24 (A2202 study), compared to 31.7% in Asian patients and 41.9% in Western patients (COMFORT-I). Furthermore, treatment-related anemia and thrombocytopenia frequently necessitate dose reductions or discontinuation, with over 60% of patients requiring dose modification due to adverse events. Hydroxyurea (HU) is commonly used as cytoreductive therapy in China, but its efficacy in treating MF-associated splenomegaly is variable and typically limited to approximately one year; nearly 50% of patients experience worsening anemia or cytopenia with HU therapy.
Jaktinib (also known as gecacitinib) is a novel inhibitor targeting both JAK and ACVR1. By inhibiting JAK1, JAK2, JAK3, and TYK2, it blocks the JAK-STAT signaling pathway, thereby alleviating inflammation and splenomegaly. Through a mechanism shared with momelotinib, jaktinib inhibits ACVR1 activity, which downregulates hepcidin expression, improves iron metabolism imbalance, and increases hemoglobin levels, thereby reducing the occurrence of anemia and transfusion dependency in patients with MF. This dual mechanism makes jaktinib particularly well-suited for MF patients who present with or are at risk of developing anemia. Multiple clinical trials of jaktinib in MF have been conducted in China. The phase II study ZGJAK002 (NCT03886415) enrolled 118 patients with intermediate- or high-risk MF and demonstrated a SVR35 rate of 44.5% at week 24 (54.8% in the 100 mg twice-daily group vs. 31.3% in the 200 mg once-daily group, p = 0.0199), with TSS50 response rates of 69.6% and 57.5%, respectively, and low incidences of grade ≥3 drug-related anemia (24.0%) and thrombocytopenia (12.5%). The phase III study ZGJAK016 (NCT04617028) compared jaktinib with HU in JAK inhibitor-naïve intermediate- to high-risk MF patients. The results demonstrated that jaktinib is superior to HU in reducing spleen size, with favorable safety and tolerability, and may offer potential improvements in patients' quality of life. Furthermore, 2026 guidelines of the Chinese Society of Clinical Oncology (CSCO) have recommended jaktinib as a Category I core agent for patients with intermediate- or high-risk MF, as well as low-risk MF with symptomatic disease, further validating its role in first-line management.
Given this robust clinical evidence, the present multicenter, prospective, real-world observational study aims to evaluate the effectiveness and safety of jaktinib in patients with newly diagnosed MF treated under routine clinical practice. As a non-interventional study, it will not influence treatment decisions but will systematically capture longitudinal data to reflect actual clinical outcomes. The primary endpoint is the proportion of patients achieving anemia response at week 24, defined as an increase in hemoglobin level or a reduction in transfusion requirement according to predefined criteria (e.g., IWG-MRT criteria). Secondary endpoints include MF-related symptom response rate (≥50% reduction in MPN-SAF TSS, TSS50) at week 24, the proportion of patients achieving ≥35% spleen volume reduction (SVR35) at week 24, progression-free survival (PFS), leukemia-free survival (LFS), overall survival (OS), and safety/tolerability assessed by adverse events, serious adverse events, laboratory abnormalities, and treatment discontinuation rates. This study will generate essential real-world evidence on jaktinib in newly diagnosed MF, providing clinicians with data to optimize first-line treatment strategies and improve long-term outcomes in this patient population.
625 studies on the registry are indexed under Primary Myelofibrosis; 124 are open to participants now.
This study's planned enrollment of 80 is below the median of 125 across 73 observational studies indexed under Primary Myelofibrosis.
Browse Primary Myelofibrosis studies →Affiliated Hospital of Nantong University is the lead sponsor of 97 studies on the registry; 57 are open to participants now.
Compared within Primary Myelofibrosis, this study's primary condition as ClinicalTrials.gg classifies it; the registry's first condition term is Myeloproliferative Disorders. The counts are of registry records indexed under each term, refreshed daily. How we classify →
Myelofibrosis patients receiving jaktinib treatment
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
A line of therapy is one course of treatment, which may combine several drugs. First-line is the first course given; second-line follows when that stops working or is not tolerated.
“Two prior lines” means two courses that count separately under the study’s rules — not simply two drugs. Ask the study team if you are unsure how yours are counted.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
A score of how well the liver works in people with liver disease such as cirrhosis: class A is mild, B moderate and C severe.
GFR (glomerular filtration rate) is how much blood the kidneys filter each minute. It is usually estimated from a blood test — eGFR, by formulas such as CKD-EPI or MDRD — and some studies ask for it to be measured directly instead. Usually given in mL/min/1.73 m².
Check the method, the units and the minimum the study states. A value of 90 or above is in the normal-or-high range, but kidney damage can show in other tests too.
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.
Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Line of therapy
A line of therapy is one course of treatment, which may combine several drugs. First-line is the first course given; second-line follows when that stops working or is not tolerated.
“Two prior lines” means two courses that count separately under the study’s rules — not simply two drugs. Ask the study team if you are unsure how yours are counted.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Cancer (malignancy)
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Child-Pugh class
A score of how well the liver works in people with liver disease such as cirrhosis: class A is mild, B moderate and C severe.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
GFR and eGFR (kidney filtering)
GFR (glomerular filtration rate) is how much blood the kidneys filter each minute. It is usually estimated from a blood test — eGFR, by formulas such as CKD-EPI or MDRD — and some studies ask for it to be measured directly instead. Usually given in mL/min/1.73 m².
Check the method, the units and the minimum the study states. A value of 90 or above is in the normal-or-high range, but kidney damage can show in other tests too.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
HIV
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hepatitis B tests
Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.
Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Clinically significant
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Jaktinib oral 50-100 mg twice daily
anemia response
Proportion of participants achieving anemia response at week 24
Time frame: 24 weeks
TSS50
Proportion of participants with a total symptom score reduction of ≥50% (TSS50) at 24 weeks
Time frame: 24 weeks
SVR35
Proportion of participants with a spleen volume reduction of ≥35% (SVR35) from baseline at week 24
Time frame: 24 weeks
Progression-free survival (PFS)
The time from the first dose to any of the following events: spleen volume increased by ≥25% from the lowest value recorded; death of any cause.
Time frame: 24 months
Leukemia-free survival (LFS)
The time from the first dose to any of the following events: bone marrow smear showed blast cells ≥20%; peripheral blood smear blast cells ≥20% and the absolute blast count ≥1×10E9/L lasts for at least 2 weeks; death of any cause.
Time frame: 24 months
Overall survival (OS)
OS was defined as the time from the first dose to death.
Time frame: 24 months
Safety and tolerability
The safety and tolerability were evalu- ated from the first dose of jaktinib to 28 days after the last dose. Adverse events (AEs) were graded according to the Common Toxicity Criteria for Adverse Events (CTCAE) version 5.0.
Time frame: 24 months
Plan to share: No
No publications or documents are linked to this record.
Start is estimated for Nov 2026; primary completion for Dec 2027, 13 months later.
Of 23 observational studies under Primary Myelofibrosis, half reached primary completion within 34 months of starting (the median), counting those still running; a quarter within 29 and three quarters within 119. This study's planned 13 months is below that.
How these figures are worked out, and which studies are left out of them.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
This study is not yet recruiting, as verified in Aug 2026. You cannot join it, but the record below documents what was studied.
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Affiliated Hospital of Nantong University