The invention relates to an amphiphilic-BMP polymer complex which is physically and chemically stable and soluble in water, characterized in that:the amphiphilic polymers comprise a hydrophilic polysaccharide skeleton functionalized with hydrophobic substituents and hydrophilic groupsthe BMP is selected from the group of therapeutically active BMPs (Bone morphogenetic Proteins),the polymer/BMP mass ratio is lower than or equal to 700.The invention also relates to the process for preparing the amphiphilic-BMP polymer complex in an aqueous medium and in the absence of organic solvents likely to denature the protein.The invention also relates to therapeutic compositions of an amphiphilic-BMP polymer complex according to the invention.
