CytRx Corporation (Nasdaq: CYTR), a biopharmaceutical research and development company specializing in oncology, today announced it has initiated a pivotal global Phase 3 clinical trial to evaluate the efficacy and safety of aldoxorubicin as a second-line treatment for patients with soft tissue sarcoma (STS) under a Special Protocol Assessment with the FDA. Aldoxorubicin combines the chemotherapeutic agent doxorubicin with a novel linker-molecule that binds specifically to albumin in the blood to allow for delivery of higher amounts of doxorubicin (3.5 to 4 times) without several of the major treatment-limiting toxicities seen with administration of doxorubicin alone. This multicenter, randomized, open-label Phase 3 clinical trial is designed to enroll approximately 400 patients with metastatic, locally advanced or unresectable soft tissue sarcomas who have either not responded to, or have progressed following treatment with, one or more systemic regimens of non-adjuvant chemotherapies. Trial patients will be randomized 1:1 to be treated with aldoxorubicin or the investigator’s choice of an approved chemotherapeutic regimen, including doxorubicin, ifosfamide dacarbazine, pazopanib (Votrient®), or gemcitabine plus docetaxel, with up to three comparator regimens to be selected by the investigator at each clinical site. The primary endpoint of the study is progression-free survival (PFS), and secondary endpoints include overall survival, response rates and safety. In January 2014, the Company announced it has received approval from the FDA to amend the Phase 3 protocol to continue dosing patients with aldoxorubicin until disease progression (defined as an increase in the size of measurable tumors by 20% or the development of a new tumor lesion), which creates the potential for substantially improved Phase 3 efficacy results. The Company expects to complete trial enrollment in 2015. In a phase 1b/2 study, partial responses were observed in 5 of 13 patients with metastatic soft tissue sarcomas who had progressed following initial chemotherapy. Eight of 13 patients showed evidence of tumor shrinkage; 5 of the 8 patients had received prior doxorubicin chemotherapy and had not demonstrated tumor reduction. Updated analysis of median progression-free survival in patients has reached over 17 months without subsequent treatments.