SS109 and NovoSeven ® PK / PD Profile, and Preliminary Efficacy and Safety of SS109 on Demand Treatment

Inclusion Criteria:

1. Aged 18 to 65 years at the time of informed consent, male;

2. Patients with clinical diagnosis of hemophilia A or B (FVIII activity level ≤ 1% orFIX activity level ≤ 2% in the previous or screening period) who meet one of thefollowing conditions: FVIII or FIX inhibitor level ≥ 5 Bu/mL at screening; FVIII or FIX inhibitor level < 5 Bu/mL and ≥ 0.6 Bu/mL at screening, with a high response to coagulation factorVIII or IX for injection (i.e., the patient has a previous history of positiveFVIII/FIX inhibitor and inhibitor levels are ≥ 5 Bu/mL after reinfusion ofFVIII/FIX).

3. No active bleeding symptoms prior to the first dose;

4. Subjects or impartial witnesses fully understand and comply with the requirements ofthe study protocol and are willing to complete the study as planned, and voluntarilycooperate in providing biological samples for testing as required by the protocol;

5. Be able to understand the procedures and methods of this clinical trial, and afterfully informed consent, the patient voluntarily participates and signs the informedconsent form by the patient himself or an impartial witness.

Exclusion Criteria:

1. Patients with a known history of hypersensitivity to the investigational product orany of its components;

2. Patients with previous hypersensitivity or anaphylaxis after FVII or IgG2 injectiontherapy;

3. Patients with positive FVII inhibitors or history of positive FVII inhibitors atscreening;

4. Patients with severe anemia (hemoglobin < 60 g/L);

5. Patients with platelet count < 100 × 109/L;

6. Patients with abnormal liver and kidney function:

• Alanine aminotransferase (ALT) or aspartate aminotransferase (AST) ≥ 3 timesthe upper limit of normal (ULN); or

• Serum total bilirubin (TBIL) ≥ 1.5 times ULN; or

• Serum creatinine (Cr) ≥ 1.5 times ULN or creatinine clearance < 60 mL/mincalculated according to the Cockcroft-Gault formula;

7. Patients with one or more positive tests for hepatitis B virus surface antigen (HBsAg), anti-hepatitis C virus (HCV) antibody, anti-human immunodeficiency virus (HIV) antibody, and anti-treponema pallidum hemagglutination (TPHA)-specificantibody;

8. With the exception of hemophilia A or B, any other haemorrhagic disorders orsignificantly abnormal coagulation indicators (such as platelet disease, vitamin Kdeficiency and hypofibrinogenaemia) caused by other diseases;

9. Patients with fever, active infection and allergy (such as allergic rhinitis,allergic asthma, allergic dermatitis) within 2 weeks before the first dose;

10. Patients with severe cardiovascular and cerebrovascular diseases or thromboembolicdiseases occurred within 6 months before the first dose, such as cerebral arteritis,moyamoya disease, cerebral stroke, viral myocarditis, endocarditis, endocardialfibroelastosis, severe arrhythmia, myocardial infarction, unstable angina pectoris,congestive heart failure (New York Heart Association Grade ≥ III), uncontrolledhypertension (systolic blood pressure ≥ 160 mmHg or diastolic blood pressure ≥ 100mmHg) and uncontrolled diabetes;

11. Patients receiving or planning to receive immune tolerance induction (ITI) treatmentduring the trial;

12. Receipt of any product containing FVII or FVIIa (plasma source or recombinant)within 24 hours before the first dose;

13. Receipt of any product containing FVIII (plasma source or recombinant) within 72hours or 5 half-lives (whichever is longer) before the first dose or any productcontaining FIX (plasma source or recombinant) within 96 hours or 5 half-lives (whichever is longer) before the first dose;

14. Patients who have used any anticoagulants, antifibrinolytic agents, and chemicaldrugs, biological products or traditional Chinese medicines affecting plateletfunction within 1 week before the first dose, including non-steroidalanti-inflammatory drugs (NSAIDs) such as aspirin;

15. Patients who have received emicizumab within 6 months before the first dose;

16. Patients who have received immunomodulators (such as gamma globulin,interferon-alpha and prednisone > 10 mg/d [and > 7 days] or similar drugs, exceptantiretroviral drugs) within 2 weeks before the first dose;

17. Patients who have received whole blood or plasma therapy within 2 weeks before thefirst dose;

18. Received vaccination within 4 weeks before the first dose or planned vaccinationduring the PK study;

19. Patients who underwent major surgical operations (e.g. orthopedic surgery, abdominalsurgery) within 1 month before the first dose, or plan to undergo surgery during thestudy period;

20. Patients who enrolled in other clinical trials within 1 month before the first dose;

21. Patients with a history of drug abuse or alcoholism;

22. Patients suffering from mental illness or obvious mental disorders, or incapacity orcognitive inability due to other causes;

23. Patients who have fertility plan or sperm donation plan during the whole trialperiod and within 3 months after administration, or are unwilling to take effectivephysical contraception measures (such as condom, diaphragm, intrauterine device);

24. Patients who have clinically significant diseases or other reasons that, in theopinion of the investigator, make participation in the clinical trial inappropriate (e.g., patients who cannot benefit from the clinical trial);

25. Subjects who, in the opinion of the investigator, have poor compliance that are notevaluable for efficacy or are expected to have a low likelihood of completing theintended course and follow-up.