Efficacy and Safety Study of Octafibrin for On-demand Treatment of Acute Bleeding and to Prevent Bleeding During and After Surgery

Inclusion Criteria: * Aged ≥12 years (only 18 and above in Russia) * Documented diagnosis of congenital fibrinogen deficiency, expected to require on-demand treatment for bleeding or surgical prophylaxis: * Fibrinogen deficiency manifested as afibrinogenaemia or severe hypofibrinogenaemia. * Historical plasma fibrinogen activity of \<50 mg/dL or levels below the limit of detection of the local assay method. * Expected to have an acute bleeding episode (spontaneous or after trauma) or planning to undergo elective surgery. * Informed consent signed by the subject or legal guardian. Exclusion Criteria: * Life expectancy \<6 months. * Bleeding disorder other than congenital fibrinogen deficiency, including dysfibrinogenaemia. * Prophylactic treatment with a fibrinogen concentrate. Treatment with: * Any fibrinogen concentrate or other fibrinogen-containing blood product within 2 weeks prior to start of treatment for the bleeding episode or surgery. * Any coagulation-active drug (i.e., non-steroidal anti-inflammatory drugs, warfarin, coumarin derivatives, platelet aggregation inhibitors) within 1 week prior to start of treatment for the bleeding episode or surgery, or as a planned or expected medication during the time period from Day 1 until 24 hours (i.e., 1 day) after the last Octafibrin infusion. Presence or history of: * Hypersensitivity to study medication. * Deep vein thrombosis or pulmonary embolism within 1 year prior to start of treatment for the bleeding episode or surgery. * Arterial thrombosis within 1 year prior to start of treatment for the bleeding episode or surgery * Hypersensitivity to human plasma proteins. * Oesophageal varicose bleeding. * End-stage liver disease (i.e., Child-Pugh score B or C). Pregnant women within the first 20 weeks of gestation. Currently breast-feeding. Known positive HIV infection with a viral load \>200 particles/μL or \>400,000 copies/mL. Polytrauma 1 year prior to start of treatment for the bleeding episode or surgery. Diagnosis or suspicion of a neutralizing anti-fibrinogen inhibitor currently or any time in the past. Acute or chronic medical condition which may, in the opinion of investigator, affect the conduct of the study, including * Subjects receiving immune-modulating drugs (other than anti-retroviral chemotherapy) such as alpha-interferon, prednisone (equivalent to \>10 mg/day), or similar drugs at study start. * Subjects having evidence or a history (within the previous 12 months) of abuse of any licit or illicit drug substance. Participation in another interventional clinical study currently or during the past 4 weeks.