CytRx Corporation (NASDAQ: CYTR), a biopharmaceutical research and development company specializing in oncology, announced today that it has reached an agreement with the U.S. Food and Drug Administration (FDA) under a special protocol assessment (SPA) for a global pivotal Phase 3 trial with aldoxorubicin as a treatment for patients with soft tissue sarcomas who have relapsed or were refractory following prior treatment with chemotherapy. The SPA is a written agreement between the Company, as the trial's sponsor, and the FDA regarding the design, endpoints and planned statistical analysis approach of the Phase 3 clinical trial to be used in support of a potential New Drug Application (NDA) for aldoxorubicin. The Company is actively making preparations for the pivotal Phase 3 trial.
“Multiple chemotherapy regimens have been explored as palliative therapy for these patients with several failures in Phase 3 trials. Additionally, currently approved chemotherapeutic regimens are frequently quite toxic with no significant impact on either progression-free survival or overall survival.”
"By reaching an agreement on an SPA, the FDA deems that results from this single Phase 3 clinical trial will be acceptable to support the regulatory approval of aldoxorubicin as a second-line treatment for patients with soft tissue sarcoma, with final marketing approval dependent on the results of the trial and other accomplishments," said Steven A. Kriegsman, CytRx President and CEO. "The ability to conduct the clinical trial under an SPA could save significant time compared with a standard regulatory pathway. Our optimism about aldoxorubicin's prospects in this difficult-to-treat indication is predicated on positive results from a Phase 1b/2 trial in which this novel agent was associated with objective responses and prolonged progression-free survival in several patients with advanced soft tissue sarcoma who had relapsed or not responded to prior treatments, as well as on additional clinical and preclinical data."
The international, open-label pivotal Phase 3 clinical trial will 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 to include dacarbazine, pazopanib (Votrient®), gemcitabine plus docetaxel, doxorubicin or ifosfamide, with up to three comparator regimens to be selected by the investigator at each clinical site. The clinical trial will be conducted at approximately 80 clinical sites in the U.S., Europe, China, Canada, Latin America and Australia. The primary endpoint of the study is progression-free survival, and secondary endpoints include overall survival and safety.
"There is a critical need for a second-line treatment for patients with soft tissue sarcomas that improves clinical benefit with fewer side effects," said Daniel Levitt, M.D., Ph.D., CytRx Executive Vice President and Chief Medical Officer. "Multiple chemotherapy regimens have been explored as palliative therapy for these patients with several failures in Phase 3 trials. Additionally, currently approved chemotherapeutic regimens are frequently quite toxic with no significant impact on either progression-free survival or overall survival."
In the Phase 1b/2 clinical trial in patients with advanced soft tissue sarcoma treated with aldoxorubicin in up to eight cycles at the maximum tolerated dose, 77% (10 of 13) of the evaluable patients showed clinical benefit, defined as partial response with tumor shrinkage in excess of 30% or stable disease at four months following treatment. None of the patients in the Phase 1b/2 trial showed cardiotoxicity and there were no drug-related patient deaths. Patients in this trial showed progression-free survival of approximately 6.4 months, with a range of 1.0 months to more than 10.7 months. This compares favorably with the median estimated progression-free survival for advanced soft tissue sarcoma patients of approximately 3 months.