Axitinib is a “promising” treatment option for unresectable and metastatic carcinoid tumors, according to a preliminary analysis of data from a small phase 2 clinical trial (NET Abstract #C9) presented at the 7th Annual Neuroendocrine Tumors (NET) conference in Nashville, TN. The meeting was organized by the North American Neuroendocrine Tumors Society (NANETS).
“The 12 month [progression-free survival (PFS)] rate associated with axitinib in advanced carcinoid tumors is promising when compared to results observed in phase 2 studies of other antiangiogenic TKIs such as sunitinib or pazopanib,” said lead study author Mauro Cives, MD, of the H. Lee Moffitt Cancer Center and Research Institute in Tampa, FL, and colleagues. “Although rates of hypertension were high, axitinib treatment was overall well tolerated.”
The coauthors enrolled 30 patients with advanced carcinoid NETs, of whom 22 could be assessed for response.
Axitinib (5 mg, twice daily) was associated with a PFS rate of 65% (SD ± 13%) at 12 months, they reported. The 1-year overall survival (OS) rate was 93% (SD ± 4.9%).
Median PFS has not yet been determined due to the small number of events.
Axitinib was also associated with a 90% hypertension rate in this study, with grade 3 hypertension occurring in 18 (60%) of study participants, and grade 4 hypertension being observed in 2 (7%) of patients. Hypertension led to treatment discontinuation in 2 patients, they reported; interruption “prompted a fast recovery without sequelae,” they reported.
Among 25 patients whose Chromogranin A (CgA) levels were elevated at baseline, “only 4 experienced major reductions (>50%) of the tumor marker,” the authors noted.
Neuroendocrine tumors are “highly vascularized neoplasms overexpressing [vascular endothelial growth factor] (VEGF) as well as VEGFR [VEGF receptor],” the researchers said. Axitinib is a tyrosine kinase receptor inhibitor that targets VEGFR-1, -2 and -3, and platelet-derived growth factor receptor (PDGFR)-β.