Target therapy for metastatic alveolar soft part sarcoma: a retrospective study with 47 cases

BACKGROUND: Alveolar soft part sarcoma (ASPS) is a translocation-associated soft-tissue tumor resistant to conventional cytotoxic agents. This report aims to compare the efficacy of anlotinib versus pazopanib as targeted monotherapy in metastatic ASPS and to determine the impact of drug dosage reduction on disease control. METHODS: Sixteen and 31 patients with metastatic ASPS were respectively treated with anlotinib and pazopanib monotherapy at a single institution. Objective response rate (ORR), progression-free survival (PFS), and overall survival (OS) were retrieved and compared between both therapeutic arms. Adverse events (AEs) within each group were recorded. Kaplan-Meier survivorship curves computed the impact of drug dosage reduction on PFS. RESULTS: The anlotinib group showed an ORR of 31.2%, compared to 35.5% in the pazopanib arm (P=0.772). Median PFS was 23.6 months [95% confidence interval (CI), 16.2–31.0 months] in patients treated with anlotinib, but dropped to 13.7 months (95% CI, 10.8–16.7 months) in those managed with pazopanib (P=0.023). One (6.3%) patient on anlotinib and 11 (35.5%) on pazopanib developed AEs requiring drug dosage reduction (P=0.029), which significantly reduced patients’ PFS in the latter setting (10.5 vs. 15.8 months, P=0.012). In patients without dosage reduction, anlotinib showed a bordering advantage than pazopanib on median PFS (24.5 vs. 15.8 months, P=0.112). CONCLUSIONS: Compared to pazopanib, anlotinib yielded longer PFS and lower incidence of AEs in ASPS patients. Drug dosage reduction was more frequently encountered with the former agent and affected the disease control.