Efficacy and Safety Evaluation Study of SCT800 in Previously Untreated Hemophilia A Patients.

SCT800 is a recombinant human coagulation factor VIII, which was on market in 2021 in China. The indication of SCT800 is prophylaxis and control of bleeding events in adult and children, and for the perioperative management of bleeding events. This study continued to evaluate the safety and efficacy of SCT800 in previously untreated patients with severe haemophilia A.

• SCT800 prophylaxis and treatment for bleeding events (Drug): For prophylaxis, 15-50 IU/kg SCT800 is intravenously. For control of bleeding events(BE), 10-20 IU/kg for mild BE, 15 -30IU/kg for moderate BE, 30-50IU/kg for severe BE.

Primary outcomes

• Incidence of FVIII inhibitor [up to 50-100 Exposure Days]: The percentage of FVIII inhibitor measured by Nijmegen-Bethesda

Secondary outcomes

• The percentage of adverse events [up to 50-100 exposure days]
• annualized bleeding rate [up to 50-100 exposure days]: Annualized Bleeding Rate（ABR） can be calculated using the following formula: Number of bleeding events in efficacy evaluation period/(number of days in treatment period/365.25)
• annualized joint bleeding rate [up to 50-100 exposure days]: Annualized joint bleeding rate（AJBR） can be calculated using the following formula: Number of joint bleeding events during efficacy evaluation period/(number of days in treatment period/365.25).
• consumption of SCT800 [up to 50-100 exposure days]: consumption of SCT800 per month and per year
• hemostatic effect of SCT800 [up to 50-100 exposure days]: The investigator shall evaluate the hemostatic effect after the treatment of every bleeding event of subjects based on a four-point scale(excellent, good, moderate, not relieved).

Sex: Male, ages: any to 6 Years

Inclusion Criteria:

* Male subjects with severe hemophilia A (FVIII:C < 1% in central laboratory tests)
* previously untreated with pdFVIII/rFVIII, including marketed SCT800 (those who have previously used ≤5EDs of blood products such as cryoprecipitate or fresh frozen plasma are acceptable).
* FVIII inhibitor negative
* informed consent.

Exclusion Criteria:

* Known allergy to recombinant coagulation factor VIII concentrate or any excipient; known allergy to bovine, rodent or hamster bovine;
* subjects with a history or family history of FVIII inhibitor formation;
* Clinical liver function test (ALT、AST) ≥ 5 ULN or clinical kidney function test (BUN，Cr) ≥2 ULN;
* Patients with other coagulation dysfunction diseases in addition to hemophilia A.
* International Normalized Ratio (INR) > 1.5.