CABOSUN
In previously untreated intermediate/poor-risk metastatic RCC, does cabozantinib improve PFS versus sunitinib?
Absolute Effect
A fixed-time PFS rate was not reported in the primary publication, so NNT is not calculated. The median difference (3.3 months) is descriptive and is not converted into NNT.
Subgroups: PFS results were consistent across IMDC risk and bone-metastasis strata; MET expression did not identify a clear predictive subgroup.
Safety: Grade 3–4 adverse events occurred in 68% vs 65%. The small phase II sample and open-label design limit precision for toxicity and OS.
Interpretation & limitations
CABOSUN is important as a randomized demonstration of activity of cabozantinib versus an older VEGFR-TKI comparator, but its small sample and phase II design make fixed-time absolute benefit estimation inappropriate.
Primary source
Choueiri TK, et al. J Clin Oncol. 2017;35:591–597; updated OS analysis.