# Comparative Outcomes of Brachyury Vaccine vs. Imatinib in Advanced Chordoma: A Mayo Clinic Experience

## TL;DR

This study compares a vaccine and a drug for treating advanced chordoma, finding the drug controls disease longer but with similar survival and fewer severe side effects.

## Contribution

The study provides a comparative analysis of brachyury vaccine and imatinib in chordoma treatment using real-world patient data.

## Key findings

- Imatinib showed longer time to progression compared to the brachyury vaccine.
- The brachyury vaccine had more frequent but milder adverse events than imatinib.
- Overall survival was similar between the two treatment groups.

## Abstract

Chordoma is a rare, slow-growing cancer that affects the bones of the spine and skull base, with no FDA-approved therapies to date. Current therapies often provide limited benefit, and better options are needed. We compared two treatments: imatinib, a targeted therapy, and an experimental vaccine designed to stimulate the immune system. By reviewing data from patients at our institution, we evaluated their effectiveness and side effects. Our findings offer insight into the strengths and limits of current treatments and highlight the need for new approaches. This research provides a foundation for future studies to improve care and quality of life for patients with chordoma.

Background/Objectives: Chordoma, a rare slow-growing malignant bone tumor, remains therapeutically challenging due to its invasive nature. We examined institutional outcomes comparing imatinib and brachyury-directed vaccines. Methods: We used data from three sites of our quaternary care academic institution to analyze demographics, time to progression, overall survival, and adverse events in chordoma patients treated with imatinib or enrolled in a brachyury vaccine trial. Results: We included a total of 52 patients (8 in the brachyury vaccine cohort and 44 in the imatinib cohort) in the analysis. As expected, sacrococcygeal location was the most predominant in both cohorts: 62.5% in the brachyury cohort and 45.5% in the imatinib cohort. No demographic differences were present between the cohorts. ECOG was similar in both groups (p = 0.796). The primary outcome, time to progression (TTP), was shorter in the brachyury compared to the imatinib cohort (5.6 vs. 13 months, p = 0.0589), almost reaching statistical significance. Overall survival (OS) was comparable, 211 vs. 212 months for the brachyury and imatinib cohorts, respectively (p = 0.277). Although the brachyury vaccine cohort presented a higher incidence of adverse events than the imatinib cohort (75% vs. 31.8%, p = 0.021), the severity was milder. Conclusions: Imatinib showed longer disease control than the brachyury vaccine, though overall survival was similar. Future studies and deeper molecular insights are essential to develop better therapies and improve patient quality of life.