A biodegradable bone replacement material for the treatment of bone defects and delivery of antibiotic compounds, particularly for treating bone infections, comprising calcium sulfate hemihydrate, calcium sulfate dihydrate, an antibiotic mixture comprising a tetracycline compound and an ansamycin compound. Preferably, the ratio of calcium sulfate hemihydrate to calcium sulfate dihydrate is from 1:1 to about 3:1. Methods for treating, repairing or augmenting an osseous defect using the bone replacement material are also provided.