2 targeted therapies act against Ewing's sarcoma tumors

Public release date: 31-Mar-2012 [ | E-mail | Share ]

Contact: Scott Merville smerville@mdanderson.org 713-792-0661 University of Texas M. D. Anderson Cancer Center

CHICAGO - A pair of targeted therapies shrank tumors in some patients with treatment-resistant Ewing's sarcoma or desmoplastic small-round-cell tumors, according to research led by investigators from The University of Texas MD Anderson Cancer Center reported at the AACR Annual Meeting 2012.

Five of 17 Ewing's sarcoma patients responded to the combination, with two achieving complete responses, one for 27 weeks. The researchers noted that the ability to manage patients' treatment-related side effects is vital to maintaining the therapy and slowing disease progression.

The study was published simultaneously in Clinical Cancer Research, a journal of the American Association for Cancer Research.

Ewing's sarcoma primarily affects the bones and occurs most often in teenagers and young adults and relapse is common, said lead researcher Aung Naing, M.D., assistant professor in MD Anderson's Department of Investigational Cancer Therapeutics.

Researchers used a combination of cixutumumab, a human IgG1 monoclonal antibody that targets insulin growth factor receptor 1 (IGF-1R), and temsirolimus, an agent that inhibits mTOR, or "mammalian target of rapamycin". The two drugs address molecular pathways that cause cell proliferation and survival, abnormal blood vessel growth and resistance to chemotherapy and radiotherapy.

Encouraging Responses in Treatment-Resistant Patients

Twenty patients were enrolled in the phase I clinical trial - 17 with Ewing's sarcoma and three with desmoplastic small-round cell tumors (DSRCT). The patients were treated with cixutumumab (6 mg/kg i.v. each week) and temsirolimus (25 to 37.5 mg i.v. each week) in 4-week cycles. Median follow-up was 8.9 months.

"Seven of the 20 patients responded and have had stable disease for more than five months," Naing said. "Five of these responders have Ewing's sarcoma and have had tumor reductions of more than 20 percent. Treatment responses have lasted 8 to 27 months."

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2 targeted therapies act against Ewing's sarcoma tumors