Funded in partnership with Quad W
One of the most promising approaches for patients with advanced Ewing sarcoma is the use of therapies directed against the insulin-like growth factor-1 receptor (IGF-1R). Preclinical studies provide strong biologic rationale for targeting the IGF-1R pathway in Ewing sarcoma. Early clinical studies of monoclonal antibodies directed against IGF-1R have demonstrated that patients with relapsed Ewing sarcoma have one of the highest response rates to this class of agents. However, only a minority of patients with relapsed Ewing sarcoma responds to IGF-1R inhibition, though often with dramatic clinical responses.
Based on these promising results, the clinical development of IGF-1R inhibitors for patients with Ewing sarcoma is a high priority. The Children’s Oncology Group (COG) is soon to activate a randomized phase II trial for patients with newly diagnosed metastatic Ewing sarcoma to compare standard multiagent chemotherapy to this same chemotherapy with the addition of an anti-IGF-1R monoclonal antibody. I will chair this important clinical trial that has the potential to transform the care of patients with metastatic Ewing sarcoma.
A major component of this trial will be an evaluation of potential predictors of patients with metastatic Ewing sarcoma who are most likely to benefit from IGF-1R inhibition. Identification of these predictors is absolutely critical since data from patients with relapsed Ewing sarcoma suggest that that only a subset of patients will respond to this therapy. This trial provides an ideal and unique opportunity to investigate potential predictive markers of response to IGF-1R inhibition in this disease, both because it is a randomized trial and because it will be the first large-scale evaluation of IGF-1R inhibition in patients with newly diagnosed Ewing sarcoma.
All 126 patients enrolled to the trial will participate in the correlative studies. By evaluating these potential markers in patients treated with and without the IGF-1R inhibitor, we will be able to distinguish prognostic markers from markers that are predictive of response to this targeted therapy.
We will assess several promising markers in this trial, including:
- Tissue markers of IGF-1R expression and IGF-1R pathway activation;
- Expression of IGF-1R on bone marrow tumor cells at diagnosis and over time in response to IGF-1R inhibition;
- Serum markers of the IGF-1R pathway at diagnosis and over time in response to IGF-1R inhibition, including IGF-1, IGF-2, IGFBP3, and growth hormone; and
The COG has funds to conduct this trial, but does not have funds to support the critical embedded correlative biology studies embedded within this trial. Therefore, we are seeking funds to support processing and analysis of samples obtained. Some of these funds will be used directly at UCSF as the evaluation of bone marrow tumor cells is performed at UCSF using only fresh samples. Additional funds would be used by the COG Biopathology Center at Nationwide Children’s Hospital in Columbus, Ohio to support the processing of samples into serum and DNA for testing.
