(P 193) Recent Trends in Sarcoma Trials for Children in the United States

Objective: Sarcomas require new therapies to improve cure rates. Sarcomas occur in children and adults, thus inclusion of children (patients under 18 years of age) in sarcoma studies is critical. Our objective was to evaluate recent sarcoma trials enrolling children to determine temporal trends in therapeutic trials available to children with sarcoma in the United States (US).

Methods: Using sarcoma-focused search terms, ClinicalTrials.gov was queried for studies 1) with a lower-bound age limit ≤17 years, regardless of upper age limit, 2) identified as interventional, 3) with a study start between September 27th, 2007 and January 11th, 2023, and 4) with ≥1 site in the US. Studies were categorized by cancer type, intervention type, age range eligible, funding source, study location, number of sites, and study status. Trials were examined as a whole and stratified to compare 1) Pediatric trials (defined here as enrolling ≤21 years of age) vs. Adult/Pediatric trials (enrolling >21 years of age) and 2) trials receiving industry funding vs. no industry funding. Continuous variables were compared by parametric or non-parametric tests according to the sample distribution. Categorical variables were compared using Chi-square tests or Fisher’s exact test. All statistical tests were two-sided and a p-value < 0.05 was considered statistically significant. The Mandal-Kenn test was used to investigate temporal trends in trial frequency.

Results: Of 273 trials included, 215 (79%) were pediatric/adult while 58 (21%) were pediatric. The most common cancer types were mixed (n=70, 25%), multiple solid tumors (n=64, 23%), and multiple sarcoma types (n=59, 22%). Most trials were Phase 1/2 or Phase 2 (n=161, 59%). The most common intervention was drug/biologic agents (n=199, 73), while 31 trials (11%) involved stem cell transplant/cell therapy and 31 trials (11%) used multiple interventions. Most trials received no industry funding (n=155, 57%), were exclusive to the US (75%), and were multi-institutional (n=180, 66%). Eighty-three trials (30%) were completed with a median duration of 4 years (range 0.8-9.8 years). Twenty-three trials (8.4%) were terminated, most commonly due to slow accrual (39%) and drug development decision (26%). Only five trials enrolled exclusively patients < 18 years old; all were Phase 1 or 2, all studied drug/biologic therapies, and three of five were industry-supported.
Pediatric trials were more likely to enroll mixed cancer types, while pediatric/adult studies were more likely to enroll multiple sarcoma types or focus on specific sarcomas. Similar proportions between these groups were seen across trial phase, funding source, intervention, number of sites, study location, and reason for termination. A non-statistically significant trend was noted towards shorter trial duration for pediatric studies (3.65 vs 4.8 years, P=.08). Studies with industry funding were more likely to be Phase 1/2 or Phase 2 (69% vs. 51%, P=.002). Industry-funded studies had proportionately more drug/biologic interventions 86% vs. 63%, p<.001), were more likely to be international (41% vs. 14%, P=.002) and more likely to be multi-site (76% vs. 58%, P=.002). New sarcoma trial activations increased by year from 2008 through 2022 (P=0.01). A median of 18 (range 10 to 27) sarcoma trials activated each year, peaking in 2017. No specific yearly trends were noted for trial phase, intervention type, or funding source.

Conclusion: Clinical trials enrolling children with sarcoma most often span pediatric and adult ages, are multi-institutional, and have low termination rates, most often due to slow accrual. The number of new trials increased yearly. Most trials did not receive industry funding, though those funded by industry were more likely to be early phase efforts studying novel drug or biologics and enrolling at multiple sites and internationally.