CytRx Corporation announced that an in vivo trial investigating aldoxorubicin, its tumor-targeting conjugate of the widely used chemotherapeutic agent doxorubicin, in combination with unconjugated doxorubicin, demonstrated positive results and provided the basis for the Company's current evaluation of the combination therapy in cancer patients with advanced solid tumors in a Phase 1b clinical trial. The trial compared the antitumor efficacy and tolerability of weekly intravenous treatments with saline or doxorubicin compared with three dosing regimens of either aldoxorubicin alone or combination aldoxorubicin and doxorubicin in a xenograft model of human pancreatic cancer. As single agents, doxorubicin and aldoxorubicin were administered at their maximum tolerated doses (MTD), while each agent was given at 50% of their MTD when combined.

Doxorubicin alone produced only modest tumor inhibition. Aldoxorubicin alone and each combination therapy arm induced both complete and partial remissions, with antitumor efficacy within all arms essentially identical. Importantly, the trial data showed better tolerability for the combination therapy at these low dose levels compared with single agent aldoxorubicin.