A subgroup analysis of the phase 3 CABINET trial revealed that cabozantinib (Cabometyx) significantly improved progression-free survival (PFS) in patients with advanced extrapancreatic neuroendocrine tumors (NETs) originating in the gastrointestinal (GI) tract, marking a potential advancement in the treatment of this challenging cancer. The findings, presented at the 2025 Gastrointestinal Cancers Symposium, highlight the efficacy of cabozantinib in delaying tumor growth in this patient population.
The study focused on patients with extrapancreatic NETs who had progressed after prior therapy. Patients treated with cabozantinib experienced a median PFS of 8.5 months, compared to 5.6 months in the placebo arm (stratified HR, 0.50; 95% CI, 0.28-0.88; 1-sided stratified log-rank P = .007).
Efficacy Across Subgroups
Dr. Jonathan Strosberg, leader of the Neuroendocrine Tumor Division at Moffitt Cancer Center, noted the potential benefits observed across various clinical factors, including tumor grade, functional status, concurrent somatostatin analog use, and prior treatments. The most pronounced benefit was observed in patients who had not received prior lutetium Lu 177 dotatate, had grade I disease, had an ECOG performance score of 1 or 2, and had a primary tumor site of midgut GI.
Safety Profile
The safety profile of cabozantinib was consistent with previously reported data. Grade 3 to 4 adverse events occurred in 60% of patients treated with cabozantinib, compared to 18% in the placebo group. Common adverse events included hypertension (19%), diarrhea (13%), and fatigue (10%).
Mechanism of Action and Comparison to Existing Therapies
Cabozantinib is an oral tyrosine kinase inhibitor that targets VEGFR and MET receptors on cell surfaces. Dr. Strosberg explained that while sunitinib is approved for pancreatic NETs, cabozantinib could potentially be the first in its class approved for GI-NETs. He also noted that in the CABINET study, the benefit of treatment was seen consistently across the population, regardless of whether tumors were functional or nonfunctional, or whether they originated in the midgut or non-midgut.
Study Design and Patient Characteristics
The CABINET trial enrolled patients with grade I to III well to moderately differentiated NETs who had experienced disease progression within 12 months following treatment with at least one prior FDA-approved systemic therapy. Patients were randomized to receive either 60 mg of cabozantinib or placebo. The primary endpoint of the trial was PFS.
Baseline characteristics of the subgroup analysis showed a median age of 66 years in the cabozantinib arm and 67 years in the placebo arm. The median number of prior systemic therapies received was one in both arms. Most patients had previously received everolimus (Afinitor) or lutetium Lu 177 dotatate (Lutathera).
Implications for Treatment
The results of the CABINET trial suggest that cabozantinib could offer a valuable treatment option for patients with advanced GI-NETs who have progressed on prior therapies. The observed PFS benefit and manageable safety profile support its potential role in delaying tumor growth and improving outcomes in this patient population.
