Meta-Analysis of Pazopanib versus Other Antiangiogenic Tyrosine Kinase Inhibitors (TKIs) in Advanced STS
In addition to pazopanib, other mechanistically similar antiangiogenic TKIs have been explored in sarcomas. Although pazopanib may possess unique properties that enhance its antisarcoma activity, this activity may be a general property of antiangiogenic TKIs or a reflection of pazopanib’s clinical development. This meta-analysis was designed to distinguish these possibilities.
Selected studies included phase 2 or 3 trials available in MEDLINE and Web of Science that were conducted prior to May 2016 with either pazopanib or another TKI as monotherapy for soft-tissue sarcoma (STS). Outcomes included median progression-free survival (PFS), overall survival (OS), and overall response rate (ORR). A random effects meta-analysis was conducted with prespecified strata considered as distinct trials.
Among 253 references, 23 met inclusion criteria. The meta-analyses comparing pazopanib with other TKIs yielded, respectively, an ORR of 5.2% versus 5.6%, median PFS of 3.7 months versus 3.2 months, and median OS of 11.4 months versus 13.8 months. Median PFS and OS differed significantly by drug treatment group.
PFS was longer and OS was shorter with pazopanib compared with other antiangiogenic TKI-treated patients, suggesting that PFS may not be an ideal surrogate for OS in these trials. Further studies to clarify pazopanib’s activity as monotherapy and in selected combinations are warranted.
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