The present invention provides a composition that may be used as an implant or a bone graft substitute or extender for filling voids and/or promoting fusion of osseous tissues. The implant may comprise ceramic granules such as calcium phosphate granules and one or more polysaccharide excipients, and may be in the form of a putty or flowable paste. Optionally, the implant may also comprise a growth factor such as a bone morphogenetic protein.