Clinical trial Recruiting at 1 site Phase1; Phase2 Interventional Ages 18 and up Men only

Evaluating ZS801 for treating Hemophilia B in adults

Official title: A Non-randomized, Open-label, Dose-escalation, Phase I/II Study to Evaluate the Safety, Tolerability, Kinetics and Efficacy of a Single Intravenous Infusion of ZS801 in Hemophilia B Subjects With Endogenous FIX ≤2%.

Run by Institute of Hematology & Blood Diseases Hospital, China · NCT05641610 · Data updated 2026-11-12

This study is testing a new treatment called ZS801 to see if it can safely help adults with hemophilia B improve their blood-clotting factor levels.

More Hemophilia B trials

Quick facts

PhasePhase1; Phase2
Study typeInterventional
Ages18 Years and up
SexMen only
Enrollment21 (estimated)
SponsorInstitute of Hematology & Blood Diseases Hospital, China
Academic / other
Locations1 site (Tianjin, Tianjin Municipality)
StatusRecruiting
StartedFebruary 16, 2022
Main results expectedDecember 2025
Study endsDecember 2028
Registry record updatedFebruary 24, 2025
Trial IDNCT05641610 on ClinicalTrials.gov

Is this trial a fit for you?

Likely a good fit

Ideal candidates are adult males aged 18 and older with a confirmed diagnosis of hemophilia B and endogenous FIX levels of 2% or less.

Probably not a fit

Patients who are hypersensitive to any components of the study drug or unable to tolerate immunosuppressants may not benefit from this study.

A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.

What this trial studies

This is a non-randomized, open-label, dose-escalation study assessing the safety, tolerability, kinetics, and efficacy of a single intravenous infusion of ZS801 in adult patients with hemophilia B. The trial will enroll 16 patients in a dose-escalation phase, followed by a dose-expansion phase involving 5 additional patients. Participants will undergo screening assessments and will be monitored for 52 weeks post-infusion to evaluate the treatment's effects on blood-clotting factor IX levels and overall safety.

Why it matters

Potential benefit: If successful, this treatment could significantly improve the management of hemophilia B by increasing endogenous factor IX levels and reducing bleeding episodes.

How similar studies have gone: While gene therapy approaches for hemophilia have shown promise in other studies, this specific treatment with ZS801 is novel and has not been previously tested.

Who can join: the full rules

Show full inclusion / exclusion criteria
Inclusion Criteria:

1. Male ≥18 years of age;
2. Confirmed diagnosis of hemophilia B, and endogenous FIX ≤2%;
3. Have had ≥100 prior exposure days (EDs) to any recombinant and/or plasma-derived FIX protein products;
4. The subject had at least 3 or more bleeding events and/or chronic hemophilia arthritis in one or more joints in the previous 1 year requiring treatment with FIX;
5. Agree to use reliable barrier contraception and prohibition of sperm donation until 52 weeks after the administration of ZS801.
6. Subjects voluntarily participate and are fully informed, fully understand the research and can comply with the requirements of the research protocol, are willing to complete the research as planned, and voluntarily cooperate with the provision of biological samples for testing.

Exclusion Criteria:

1. Hypersensitivity to any component of the study drug (including immunosuppressants) or a condition that can not use;
2. Inability to tolerate immunosuppressants or steroid drugs;
3. Have FIX inhibitor as assessed by laboratory, or documented history of FIX inhibitor;
4. Who have a history or are currently suffering from any of the following serious clinical diseases:

   1. History of malignancy or current presence of any malignancy;
   2. Have active autoimmune disease;
   3. Severe heart disease, including angina pectoris, myocardial infarction, heart failure, clinically significant congenital heart disease, heart valve disease, arrhythmia and atrioventricular block, etc.;
   4. Have underlying liver disease or history of liver disease (such as portal hypertension, ascites, splenomegaly, esophageal varices, hepatic encephalopathy or hepatic fibrosis);
   5. Have active hepatitis B infection (HBsAg positive) or active hepatitis C infection (HCVAb positive), or are currently receiving hepatitis B or hepatitis C antiviral therapy;
   6. Diabetes mellitus that is poorly controlled after drug treatment;
   7. Uncontrolled hypertension or hypotension;
5. laboratory values:

   1. Hemoglobin\<110g/L;
   2. Platelets\<100×10\^9/L;
   3. AST, ALT, alkaline phosphatase\>2×ULN;
   4. Total bilirubin\>1.5×ULN;
   5. Creatinine\>ULN;
   6. Albumin\<LLN;
   7. HIV antibody positive or Treponema pallidum antibody positive.
6. Have AAV5 capsid neutralizing antibody titers \>1:5;
7. Those who have received clinical trials of gene therapy before screening, or have used FIX clinical trial drugs within 1 month, or participated in other drug/device clinical trials within 3 months, or plan to participate in other clinical trials during this study;
8. Those who have planned surgery within 52 weeks after the infusion;
9. Those who lost more than 400 mL of blood within 3 months before screening;
10. Those with epilepsy, history of mental illness (such as schizophrenia, depression, mania or anxiety) or obvious mental disorder, incapacitated or incapacitated by other reasons;
11. Patients with a history of drug abuse or alcoholism;
12. Investigators believe that subjects have poor compliance or are expected to be less likely to complete follow-up;
13. There are clinically significant diseases or other reasons that the researcher and/or collaborators consider unsuitable to participate in this researcher.

Where it's running

  • Institute of Hematology & Blood Diseases Hospital
    Tianjin, Tianjin Municipality, China
    Recruiting

Study contacts

Similar studies

Other studies for the same condition or treatment. Recruiting studies are listed first.

How to take part

  1. Review the eligibility criteria above with your treating physician.
  2. Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
  3. Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.
Last reviewed 2026-11-14 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.