Children’s Hospital Los Angeles has demonstrated some progress in the treatment of rhabdomyosarcoma, the most common form of soft tissue sarcoma in childhood. The Phase II clinical trial has found that by combining a molecular targeted drug called temsirolimus with chemotherapy evidences a promising treatment.
With results recently published in the Journal of Clinical Oncology, principal investigator with the Children’s Oncology Group believes this study shows real potential.
The Problem: Rhabdomyosarcoma
A rare childhood cancer that arises in the body’s soft tissues such as muscles this aggressive and highly malignant form of cancer develops from skeletal (striated) muscle cells that have failed to fully differentiate. It is generally considered to be a disease of childhood, as the vast majority of cases occur in those below the age of 18. Despite being a rare cancer, it accounts for approximately 40% of all recorded soft tissue sarcomas.
Recent estimates place the incidence of the disease at approximately 4.5 cases per 1 million children/adolescents with approximately 250 new cases in America per year.
The study sponsors sought to see if the targeted drug could be paired with chemotherapy to improve outcomes. The first every randomized trial in Rhabdomyosarcoma to test targeted agents in combination with chemotherapy in both treatment groups, the investigators compared two targeted drugs against each other: bevacizumab (inhibits the growth of blood vessels that feed tumors) and temsirolimus (inhibitor of pathway often active in rhabdomyosarcoma known as mammalian target of rapamycin (mTOR).) Both of the drugs are FDA approved.
A multicenter study enrolled 86 rhabdomyosarcoma patients who relapsed for the first time. Approximately half of the patients received bevacizumab with chemotherapy and the other half received temsirolimus with chemotherapy. The chemotherapy agents used were vinorelbine and cyclophosphamide.
The clinical trial was stopped early due to the interim analysis results revealing that temsirolimus combination was overwhelmingly superior. After the six month point, the event-free survival rate of patients receiving bevacizumab treatment ranked at 54.6% compared to expected—for temsirolimus the rate was 69.1%
Goals of the Study
The targeted goal of this study was to determine molecularly targeted agent warranted further investigation. The Children’s Oncology Group is now conducting a multicenter Phase 3 trial seeking to further understand the effectiveness of the temsirolimus-chemotherapy combination in newly diagnosed, intermediate-risk patients. The investigators seek to understand if giving this therapy early on—when the cancer is most sensitive to treatment—will improve outcomes over the long run.
Clinical Investigator Comments
Dr. Leo Mascarenhas, MD, MS Deputy Director of the Children’s Center for Cancer and Blood Diseases at Children’s Hospital of Los Angeles notes that “Prior to these results there were not compelling ideas on how to improve survival of newly diagnosed patients.”
Leo Mascarenhas, MD, MS, Deputy Director of the Children’s Center for Cancer and Blood Diseases at Children’s Hospital Los Angeles. He also directs the Sarcoma and Solid Tumor Program at CHLA and Associate Professor at Keck School of Medicine of USC
About Children’s Hospital Los Angeles
Founded in 1901, Children’s Hospital Los Angeles is ranked the top children’s hospital in California and fifth in the nation for clinical excellence with its selection to the prestigious U.S. News & World Report Honor Roll of children’s hospitals. Clinical care is led by physicians who are faculty members of the Keck School of Medicine of USC through an affiliation dating from 1932. The hospital also leads the largest pediatric residency training program at a freestanding children’s hospital of its kind in the western United States. The Saban Research Institute of Children’s Hospital Los Angeles encompasses basic, translational and clinical research conducted at CHLA.
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