Abstract: The present invention relates to modified nucleic acid sequences coding for coagulation factors, in particular human Factor VIII and their derivatives with improved stability, recombinant expression vectors containing such nucleic acid sequences, host cells transformed with such recombinant expression vectors, recombinant polypeptides and derivatives which do have biological activities of the unmodified wild type protein but having improved stability and processes for the manufacture of such recombinant proteins and their derivatives. The invention also covers a transfer vector for use in human gene therapy, which comprises modified DNA sequences.

Abstract: A DNA-construct has been disclosed which is suitable for a tissue-specific expression of a blood coagulation factor like Factor IX, which comprises a DNA coding for an amino acid sequence of a blood coagulation factor and a DNA coding for a promoter which is specific for the expression in hematopoietic cells.

Abstract: A modified factor VIII CDNA is disclosed, wherein one or more spliceable nucleotide sequences have been inserted into introns 1 and/or 13 of the wild-type factor VIII cDNA. Further, a process for the production of a biologically active recombinant human factor VIII or its derivative is disclosed, which is performed by cultivating an animal cell line comprising a recombinant expression vector containing said modified factor VIII cDNA. Moreover, a transfer vector for use in the human gene therapy is described which comprises said modified factor VIII cDNA. Finally, the use of recombinant human factor VII and its derivatives for the treatment of hemophilia is disclosed.