Biodegradable polymer compositions suitable for intraperitoneal administration to treat a mammalian subject having ovarian cancer are described, wherein the polymer compositions provide extended release of the antineoplastic agent into the peritoneum of the subject. The subject compositions can increase the median survival rate from the cancer by at least about 10%, as compared with the median survival rate obtained by administration of a composition comprising the same dosage of the antineoplastic agent without the biodegradable polymer. Solid articles and methods for treating ovarian cancer are also described.