Sunitinib administered prior to radiotherapy in patients with non-resectable glioblastoma: results of a Phase II study

Sunitinib is a tyrosine kinase inhibitor with direct anti-tumor and anti-angiogenesis activity targeting VEGFR 1-2, PDGFR alpha-beta, c-kit, bFGF, (CSF-1), FLT3 and RET. The present trial examined the activity of sunitinib in 12 patients with newly diagnosed, non-resectable glioblastoma. Patients (<= 75 years of age with performance status [PS] >= 2 and minimental status [MMS] >= 25) were treated post-biopsy with sunitinib 37.5 mg daily for 8 weeks pre-radiotherapy, during radiotherapy (60 Gy, 6 weeks) and post-radiotherapy until disease progression. The primary endpoints were overall response rate (ORR; RANO criteria) after 8 weeks of sunitinib and patient tolerance. Secondary endpoints were percentage of patients free of neurological deterioration pre-radiotherapy, percentage of patients completing radiotherapy, progression-free survival (PFS), overall survival (OS), and 1-year survival. A Simon 2-stage design (12 -> 20) based on ORR was applied to calculate the number of patients needed to detect at least 10 % response with a error of 0.05 and beta error of 0.10. The trial was closed because it did not meet minimal activity criteria. ORR was 0 % with only 1/12 patients (8.3%) achieving stable disease after sunitinib treatment. No patient showed reduction in gadolinium enhancement. The most frequent G3/4 toxicities were fatigue (24.9 %) and diarrhea (16.6 %); one patient died of a CNS hemorrhage; 10/12 patients (83.3 %) deteriorated neurologically before radiation therapy; median PFS was 7.7 weeks (95 % CI: 7.2-8.2); median OS was 12.8 weeks (95 % CI: 0.5-23.8 weeks); 1-year survival was 0 %. Sunitinib has no activity as monotherapy in glioblastoma, and further investigation of its efficacy in this setting is unwarranted.