Disclosed herein are stereocomplexes for the delivery of one or more anti-cancer agents. The stereocomplexes exhibit low toxicity and are biodegradable while also providing for controlled release of one or more anti-cancer agents at tumor sites. The stereocomplexes can be designed such that the anti-cancer agents operate synergistically and may optionally include additional targeting groups and functionalities. The stereocomplexes disclosed herein can be combined with pharmaceutically-acceptable carriers and/or excipients to form pharmaceutical compositions. By varying the amount of each anti-cancer agent in the stereocomplex, specific types of tumors and cancer cell lines can be treated.