Severe Hemophilia A

The indication for this product is to control bleeding in patients with hemophilia A (congenital deficiency of factor VIII). The primary objective: Evaluation of the efficacy of recombinant human coagulation factor VIII-Fc fusion protein for injection (FRSW107) as an on-demand treatment in previously treated patients with severe hemophilia A. Secondary objectives: Evaluation of the safety and immunogenicity of FRSW107 as an on-demand therapy in previously treated patients with severe hemophilia A. Evaluate the on-demand treatment's PK profile of FRSW107 in previously treated patients with severe hemophilia A based on population pharmacokinetic (PopPK) methods ; preliminarily investigate the exposure-response (E-R) relationship of FRSW107 on-demand treatment in these patients if data permit.

The purpose of the study is to learn about safety, how the body processes marstacimab and how it works in patients with severe hemophilia A without inhibitors. Hemophilia A is rare bleeding disorder where the blood doesn't clot normally. This causes a person to bleed a lot, even from a small cut. These patients who are on emicizumab medicine for routine prophylaxis for at least 6 months, and desire to switch to marstacimab medicine. Inhibitors are antibodies that the immune system develops because it sees the infused clotting factor as a foreign substance that needs to be destroyed. Antibodies are proteins that eat up the activated factor before it has time to stop the bleeding. Prophylaxis are preventive medicines. This study is seeking for participants: * with severe Hemophilia A withouth inhibitors who are on emicizumab treatment for at least 6 months. * must be 12 to less than 75 years old * must have a body weight of at least 35 kilograms. The results from this study will serve as a guide to doctors and their hemophilia A patients who will change their medicines in the real-world clinical setting. Patients who can take part in the study will receive marstacimab medicine as weekly injections under the skin of 150 milligrams for 4 months. Study treatment with marstacimab will be initiated no earlier than 14 days after last dose of emicizumab. The study can last up to 6 months. The sponsor will provide marstacimab. Patients will continue their usual treatment with the infused clotting factor for their bleeds when taking part in the study. Roll-over into an optional study treatment extension period will be available to participants who wish to continue prophylaxis with marstacimab in countries where it is not commercially available.

Recombinant factor VIII for the prevention of bleeding in patients with severe haemophilia A undergoing major surgery while receiving emicizumab prophylaxis

This study was divided into four stages: screening period, main trial period, extension period and follow-up period. In the main trial, both groups received FRSW107 prophylactic therapy. The recommended initial dose of prophylactic administration was 50 IU/kg, the dose range was 25 to 50 IU/kg, and the recommended frequency of administration was once every three days (Q3D). The dose range could be adjusted according to the patient's response. The main trial period was prophylaxis up to ≥50 exposure days (EDs) and ≥6 months. The investigator may adjust the dose according to the clinical efficacy of the subjects (the occurrence of bleeding and its clinical manifestations) and the concentration of FⅧ valley according to the following principles. If necessary, the investigator may adjust the dosing interval according to the clinical efficacy of the subject (the occurrence of bleeding and its clinical manifestations) and the concentration of FⅧ. Investigators are advised to inform sponsors or their research partners when adjusting doses and dosing intervals during prophylaxis. After participants completed prophylaxis until ≥50EDs and ≥6 months, participants' willingness and investigator evaluation were used to decide whether to enter the extended trial. All subjects entering the extended phase continued with the original prophylactic regimen until 100EDs was dosed. During the main trial period and the extended preventive treatment period, if the subjects have breakthrough bleeding events requiring treatment, hemostatic treatment of breakthrough bleeding with investigational drugs can be performed. The researchers can refer to the treatment guidance for different degrees of bleeding in Table 6-1. Taking into account the subject's prophylactic dose, severity of bleeding, site and extent of bleeding, clinical status, and previous PK results (if any), the investigator determines the appropriate dose to administer (recommended dose range: 25 to 50 IU/kg) and dosing times until the investigator assessed significant control of bleeding episodes (e.g. reduction of pain and swelling) or return to pre-bleeding activity. If the bleeding episode stops, the subject will continue with the same dose and frequency of prophylactic medication as before the bleeding episode.

To evaluate the prophylactic efficacy of recombinant human coagulation factor Ⅷ-Fc fusion protein (FRSW117) for injection in patients with severe hemophilia A. To evaluate the safety of recombinant human coagulation factor Ⅷ-Fc fusion protein (FRSW117) for injection in patients with severe hemophilia A. Secondary purpose: To evaluate the efficacy of recombinant human coagulation factor Ⅷ-Fc fusion protein for injection (FRSW117) in hemostasis and surgical hemostasis in patients with severe hemophilia A. To evaluate the pharmacokinetic (PK) characteristics of recombinant human coagulation factor Ⅷ-Fc fusion protein (FRSW117) for injection in treated patients with severe hemophilia A. To evaluate the immunogenicity of recombinant human coagulation factor Ⅷ-Fc fusion protein (FRSW117) for injection in treated patients with severe hemophilia A.

The goal of this observational study is to learn about the changes of antibodies and inhibitors against the coagulation factor VIII in patients with severe hemophilia A receiving emicizumab therapy. No additional visits or procedures are planned. Patients in this study will continue to receive their routine care and analysis will be done from left over samples from routine visits.