The FDA has approved cabozantinib (Cabometyx) for previously untreated patients with advanced renal cell carcinoma (RCC), based on a meaningful improvement in progression-free survival (PFS) versus sunitinib (Sutent) in the CABOSUN trial.
Cabozantinib showed similar superiority to sunitinib across all prespecified patient subgroups, including risk, bone metastases, and MET status. In those with poor-risk disease, there was a 69% reduction in disease progression or death (HR, 0.31; 95% Ci, 0.11-0.92). In the intermediate group, the HR for PFS was 0.52 in favor of cabozantinib (95% CI, 0.32-0.82).
The median duration of treatment exposure was doubled in the cabozantinib arm (6.5 vs 3.1 months) with fewer dose reductions required with cabozantinib (46% vs 35%). Treatment discontinuation due to adverse events (AEs) was similar between each group (21% vs 22%). Subsequent therapies were similar between each group.
The rate of grade 3/4 AEs was similar between the cabozantinib and sunitinib arms, respectively (68% vs 65%). Grade 5 AEs, regardless of cause, were experienced by 4% of patients in the cabozantinib arm compared with 10% in the sunitinib group.
When compared with cabozantinib, sunitinib led to higher rates thrombocytopenia (61% vs 38%), anemia (46% vs 33%), nausea (39% vs 32%), neutropenia (35% vs 15%), and leukopenia (35% vs 12%). However, compared with sunitinib, cabozantinib was associated with more diarrhea (73% vs 55%), hypertension (67% vs 44%), liver enzyme elevation (AST, 60% vs 31%; ALT, 55% vs 28%), decreased appetite (47% vs 32%) and weight loss (32% vs 17%, dysgeusia (41% vs 29%), and palmar-plantar erythrodysesthesia (42% vs 33%).
“We at the Alliance for Clinical Trials in Oncology are very gratified that the CABOSUN study supported the approval of Cabometyx for the potential first-line treatment of all patients with advanced renal cell carcinoma," senior author of the study Michael J. Morris, MD, medical oncologist at Memorial Sloan Kettering Cancer Center, and Chair of the Alliance Genitourinary (GU) Committee, said in a statement. "This trial exemplifies how NCI-sponsored studies can be efficient, accrue rapidly, and yield results highly relevant to the field."
Cabozantinib was initially approved by the FDA as a treatment for advanced RCC following one prior anti-angiogenic therapy in April 2016. This indication was based on findings from the phase III METEOR trial, in which cabozantinib showed a 4.9-month median OS benefit versus everolimus as a second-line therapy for advanced RCC. The risk of disease progression or death was reduced by 49% with cabozantinib over everolimus.
Choueiri TK, Hessel C, Halabi S, et al. Progression-free survival (PFS) by independent review and updated overall survival (OS) results from Alliance A031203 trial (CABOSUN): Cabozantinib versus sunitinib as initial targeted therapy doe patients (pts) with metastatic renal cell carcinoma (mRCC). In: Proceedings from the 2017 ESMO Congress; September 8-12, 2017; Madrid, Spain. Abstract LBA38.