Off label targeted therapy use in adolescents and young adults with sarcoma.

Abstract

e21504 Background: Outcomes for patients with metastatic or recurrent sarcomas remains dismal with < 20% overall survival. Due to the rarity of sarcomas, the development, testing, and approval of new therapies takes years. Most early phase clinical trials are restricted to adults leaving young patients with limited options. Little is known about the prevalence and clinical characteristics of patients receiving off-label targeted therapy (OLTT). In this multi-institutional retrospective review we evaluated OLTT use in this population. Methods: Patients with recurrent sarcoma diagnosed between the years of 2008 – 2016 were identified at six institutions. Charts were reviewed for OLTT use and additional clinical characteristics. ANOVA [Analysis of Variance] and Kruskal Wallis Rank sum tests were used for normally and non-normally distributed continuous data. Categorical data was analyzed using chi-squared tests or fisher exact tests. Results: The prevalence of OLTT use was 29% for the patients included in our analysis. Of the 99 cases, the mean age for OLTT was 18 years, ranging 3 – 34 years. Nearly half had recurrent tumor in multiple sites at the time of OLTT use, and 64% did not undergo resection prior to OLTT. Lack of clinical trial availability was the most common reason for OLTT use (31% of cases). The most common OLTT drug class used were tyrosine kinase inhibitors. Progression in 81% of cases was the primary reason for stopping OLTT and toxicity limited use in 12% of cases. One case had a complete response, 5 cases had a partial response and 4 cases had stable disease per RECIST. Conclusions: OLTT use is exceedingly prevalent in patients with recurrent sarcoma. Clinical trials for children and adolescents with recurrent sarcoma will identify optimal agents to improve outcomes in this understudied population.