ASPS accounts for less than one percent of soft tissue sarcomas and forms in tissues that connect, support, or surround the organs of the body. It is usually diagnosed in children and young adults, developing as a painless mass in the leg or buttock.
ASPS arises due to the breaking and joining of two chromosomes in tumor cells. An X chromosome, one of two sex chromosomes in humans, and one copy of chromosome 17, each lose a small piece, and the X chromosome piece becomes joined to the rest of chromosome 17. This process, called a chromosomal translocation, creates a fusion between two genes, ASPL (on chromosome 17) and TFE3 (on the X chromosome).When this fusion gene is expressed, the result is the formation of an aberrant fusion protein, ASPL-TFE3, not found in normal cells. The detection of this protein is used to confirm a diagnosis of ASPS, which is crucial in distinguishing it from other soft tissue sarcomas, but the protein’s exact role in disease progression is still unknown.
Even though researchers do not know the exact function of the fusion protein in this disease and therefore cannot target it directly, they do know that the cancer relies on the formation of new blood vessels to allow it to grow and spread throughout the body, especially the lungs, where multiple small nodules form. Because of this reliance on the vasculature (arrangement of blood vessels in the body), the scientists tested cediranib in ASPS because it is a drug that blocks the formation of new blood vessels.
AstraZeneca, the drug’s manufacturer, has tested the effect of cediranib in treating a variety of tumors, including lung and colorectal cancers, but ASPS is the first solid tumor that has demonstrated substantial tumor shrinkage. NCI’s Division of Cancer Treatment and Diagnosis (DCTD) supported the initial development of this drug using a cooperative research and development agreement, which is a contract between NCI and industry to further develop a technology for commercialization.
“It is unusual to see such high levels of tumor shrinkage in a cancer that traditionally has not responded to standard chemotherapy used for the treatment of sarcomas,” said Shivaani Kummar, M.D., head of early clinical trials development in DCTD. Standard chemotherapy for ASPS has shown no benefit or response.
In this trial, 33 patients ranging in age from 19 to 59 received cediranib. Of these, more than 50 percent had tumor shrinkage, and some continued to receive the treatment more than a year later.
Importantly, the reported side effects of cediranib, that include hypertension and diarrhea, were manageable.
The collaborative abilities of two of NCI’s divisions, DCTD and NCI’s Center for Cancer Research (CCR), played an important role in evaluating this new agent’s potential for the treatment of this rare tumor. The ability to bring ASPS patients from across the country to CCR’s clinical facility on the NIH campus for treatment made patient accrual for a trial in this rare tumor possible, according to Kummar.
A follow up study coordinated by NCI and conducted at the NIH Clinical Center and at several other research facilities, including two NCI-designated Cancer Centers—Dana-Farber Comprehensive Cancer Center in Boston and M.D. Anderson Comprehensive Cancer Center in Houston—is planned to confirm these promising results. The trial will compare cediranib with sunitinib, another blood vessel growth inhibitor, in patients with ASPS.
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Reference: Phase II study of cediranib (AZD2171) in patients with alveolar soft part sarcoma. To learn more visit: http://1.usa.gov/la6iqN.