(P 362) SHOULD PAZOPANIB BE USED AS A MAINTENANCE THERAPY TO IMPROVE RECURRENCE-FREE SURVIVAL AND OVERALL SURVIVAL IN PATIENTS WHO RECEIVED MAI IN SOFT TISSUE SARCOMA?

Objective: Mesna, doxorubicin, and ifosfamide (MAI) is a standard first-line regimen for advanced or high-grade soft tissue sarcoma (STS). While the combination improves response rates and progression-free survival (PFS), it has not shown a definitive overall survival (OS) benefit over doxorubicin alone. Pazopanib, an oral multikinase inhibitor, is approved for advanced non-adipocytic STS after prior chemotherapy, based on improved PFS versus placebo. Despite low response rates and no OS benefit, its tolerability makes it a potential maintenance option following induction chemotherapy. This study evaluates whether pazopanib, used as maintenance after MAI chemotherapy in advanced/aggressive STS, improves survival compared to observation alone.

Methods: A single-center retrospective cohort study was conducted under an IRB-approved protocol at the University of Miami Sylvester Comprehensive Cancer Center. From 2009 to 2025, 108 biopsy-confirmed sarcoma patients who received both MAI and pazopanib were identified. Demographic and clinical variables were extracted from medical records and stored in REDCap. A resident physician independently verified pazopanib was used as maintenance, defined as administration after completing MAI without radiographic progression. Patients with missing data were excluded. Kaplan-Meier methods estimated PFS and OS, with multivariable logistic regression to adjust for confounders.

Results: A total of 22 patients met inclusion criteria. Median age at diagnosis was 48.0 years (range 17–74); 63.6% were female, 36.4% Hispanic/Latino, and 31.8% Black. Synovial sarcoma was the most common subtype (31.8%), followed by leiomyosarcoma (13.6%). Most tumors were high-grade (72.7%), and 36.4% had metastatic disease at diagnosis. The median PFS was 19.1 months.

Conclusion: The median PFS was notably longer than historical benchmarks, including 7.4 months in the EORTC 62012 trial and 6.3 and 3.7 months for synovial and other STS subtypes, respectively, in pooled analyses. These findings suggest that maintenance pazopanib may prolong disease control in high-risk STS patients who respond to MAI. However, due to the retrospective design, small sample size, and lack of a comparator group, results should be interpreted with caution. A retrospective analysis of patients who received MAI alone is in progress to provide a comparative cohort. Ultimately, a prospective clinical trial is warranted to validate these findings and clarify the optimal role of pazopanib in this setting.

Demographic and Clinical Profile of Study Participants