Disclosed is the use of an androgenic agent (such as testosterone undecanoate, methyltestosterone or dihydrotestosterone) and an agent that blocks conversion of testosterone to estradiol in the preparation of a pharmaceutical composition for use in increasing the bioavailability of the androgenic agent and enhancing the efficacy of aromatase inhibitor treatment in a patient suffering from a hormonally active breast cancer and having received or is receiving treatment with an aromatase inhibitor, wherein the pharmaceutical composition comprises: a) a pharmaceutically effective amount of the androgenic agent and b) a pharmaceutically effective amount of the agent that blocks conversion of testosterone to estradiol, comprising: i) a steroidal aromatase inhibitor selected from a group consisting of exemestane and formestane or ii) a nonsteroidal aromatase inhibitor is selected from a group consisting of anastrozole, letrozole, vorozole, and fadrozole wherein the increase in bioavailability is relative to sole administration of the androgenic agent and the enhanced efficacy is relative to sole administration of the aromatase inhibitor.
