Pazopanib plus best supportive care improves progression-free survival compared with supportive care alone in patients with advanced gastrointestinal stromal tumors (GISTs) resistant to imatinib and sunitinib, a study published in the journal The Lancet Oncology has shown.1
GISTs are the most common mesenchymal neoplasms of the gastrointestinal tract. The standard sequence of treatment for advanced disease is imatinib followed by sunitinib and regorafenib. Although pazopanib is effective in soft tissue sarcomas, the efficacy of this TKI has never been evaluated in advanced GIST in a randomized study. Therefore, researchers sought to assess the efficacy and safety of pazopanib in patients with previously treated advanced GIST.
For the open-label, phase 2 PAZOGIST trial, researchers enrolled 81 patients with advanced GIST resistant to imatinib and sunitinib from 12 centers in France. Participants were randomly assigned 1:1 to receive pazopanib 800 mg orally once daily in 4-week cycles plus best supportive care or best supportive care alone. Patients in the best supportive care alone group who experienced disease progression were eligible to switch to pazopanib.
Results showed that at a median follow-up of 26.4 months in the pazopanib arm and 28.9 months in best supportive care alone arm, the 4-month progression-free survival rate was 45.2% (95% CI, 29.1 – 60.0) and 17.6% (95% CI, 7.8 – 30.8), respectively (HR, 0.59; 95% CI, 0.37 – 0.96; P = .029).
Median progression-free survival was 3.4 months (95% CI, 2.4 – 5.6) with pazopanib compared with 2.3 months (95% CI, 2.1 – 3.3) without pazopanib (HR, 0.59; 95% CI, 0.37 – 0.96; P = .03).
Of the 41 patients in the best supportive care alone group, 88% switched to pazopanib following disease progression. These patients had a median progression-free survival from pazopanib initiation of 3.5 months (95% CI, 2.2 – 5.2).
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In terms of safety, 72% of the 76 pazopanib-treated patients reported treatment-related grade 3 or higher adverse events. The most common was hypertension. Of note, 26% of patients who received the kinase inhibitor experienced pazopanib-related serious adverse events, including pulmonary embolism. Three patients died as a result of pazopanib treatment.
- Mir O, Cropet C, Toulmonde M, et al. Pazopanib plus best supportive care versus best supportive care alone in advanced gastrointestinal stromal tumours resistant to imatinib and sunitinib (PAZOGIST): a randomised, multicentre, open-label phase 2 trial [published online ahead of print April 5, 2016]. Lancet Oncol. doi: 10.1016/S1470-2045(16)00075-9.