Inclusion Criteria:  Patient affiliated to a social security regimen or beneficiary of the same Signed written informed consent form Confirmed diagnosis of a hematological malignancy and undergoing intensive chemotherapy, autologous stem cell transplantation or allogeneic stem cell transplantation Grade ≥ II hemorrhagic symptoms according to WWorld Health Organization classification Failure or impossibility to use Human Leucocyte Antigen-matched platelet unit Body weight between 38 and 78 Kgs Transfusion refractoriness as defined by Corrected count increment ≤ 5 and platelet level < 20.109.L-1  Exclusion Criteria:  Pregnant women Patient under guardianship or deprived of his liberty or any condition that may affect the patient's ability to understand and sign the informed consent Refusing participation Patient presenting non-malignant hematological disease Patient with high plasmatic concentration of fibrinogen (>5g/L) Patient who received fibrinogen within 20 days before inclusion Contra-indication to fibrinogen (fibrinogen concentrate) or any excipient (fibrinogen concentrate) Patient with disseminated intravascular coagulopathy Patient with thromboembolic history Patient who received L-Asparaginase or acquired hypofibrinogenemia following treatment by L-Asparaginase Patient with known risk of thrombophilia (deficiency for antithrombin 3, C protein or factor V) Patient with anti-thrombotic treatment (anti-platelet or anti-coagulant therapy) at the time of enrolment Elevated body temperature ≥ 38.5°C Hospital stay for invasive surgery Patient with acute myeloid leukemia during the induction phase of chemotherapy.