Gary Schwartz, Chief of Memorial Sloan-Kettering’s Melanoma and Sarcoma Service, describes two recent studies of new treatments for types of sarcoma, rare cancers that can affect the bones or the body’s soft tissues.
A recent phase II trial led by medical oncologist Mark Dickson focused on one of the most common types of sarcoma, called well-differentiated or de-differentiated liposarcoma, a more common type of sarcoma that originates in fat cells. The study was published online April 8 in the Journal of Clinical Oncology.
The trial was of a drug called PD0332991 (palbociclib), which targets a protein called CDK-4. That protein is overexpressed in this type of sarcoma because of a gene amplification and leads to the growth of cancerous cells. The investigators found that 70 percent of the patients did not have their disease progress during that time, which greatly exceeded the researchers’ expectations. In addition, some patients had significant shrinking of their tumors.
Another trial, published in the April issue of Lancet Oncology, was led by Dr. Schwartz. In that study, also a phase II trial, investigators combined an experimental drug called cixutumumab with temsirolimus (Torisel®), a drug already approved for some forms of kidney cancer, to treat several subtypes of bone and soft tissue sarcoma.
Cixutumumab is an antibody that targets a receptor on cancer cells known as IGF-1R. Temsirolimus blocks a cancer-related pathway called mTOR. Both IGF-1R and mTOR are critical for the growth of many sarcoma types.
The multicenter trial, which included 388 patients, found that the number of patients whose disease did not progress after 12 weeks of treatment was improved compared with other treatments. In addition, some patients with a type of sarcoma called solitary fibrous tumor had stable disease for more than a year. Patients with the subtypes Ewing sarcoma, osteosarcoma, and chondrosarcoma had partial shrinkage of their tumors.