Case Report: Should IGF-1R targeted therapy be revisited in Ewing sarcoma? a report of long-term complete response and review of the literature

Abstract

Introduction: Ewing sarcoma (ES) is a malignancy that mostly affects adolescents and young adults, with relapse or refractory cases posing major therapeutic challenges. Its unique transcriptional profile offers multiple targetable pathways, including the insulin-like growth factor-1 (IGF-1) receptor (IGF-1R) pathway. Case Report: We present the case of a 42-year-old female with recurrent ES with pulmonary metastases who, after progressing on anti-IGF-1R monotherapy with figitumumab (CP-751,871, NCT00560235), achieved complete remission in a phase I clinical trial (NCT00976508) that combined figitumumab IGF-1R-inhibition with growth hormone receptor antagonist pegvisomant. The patient has remained in long-term remission (>10 years) since the discontinuation of both agents and has not received any additional therapeutic interventions. Literature Review: We reviewed PubMed and the ClinicalTrials.gov database to identify clinical trials employing IGF-1R-targeted therapies in patients with ES and identified 24 relevant studies treating 723 patients with anti-IGF-1R therapy. Conclusion: This case represents the first report to our knowledge of patient outcomes following IGF-1R and growth hormone inhibition combination. The impressive response observed highlights the clinical synergy of this combination which warrants further clinical exploration as well as the potential of IGF-1R inhibition for ES. Additionally, this case suggests that targeted therapy discontinuation might be an option for select patients with long-term complete remission.