The KEYNOTE-B61 trial, evaluating pembrolizumab (Keytruda) plus lenvatinib (Lenvima), has demonstrated more robust data compared to the CA-209 9KU trial for the treatment of non-clear cell renal cell carcinoma (non-ccRCC). This Phase 2 trial's findings are influencing treatment paradigms for this challenging cancer subtype.
KEYNOTE-B61 Trial Details
The single-arm KEYNOTE-B61 trial enrolled 158 patients with non-ccRCC, encompassing chromophobe (n = 29), papillary (n = 93), and unclassified (n = 21) disease subtypes. The larger sample size and broader representation of histologic subtypes in KEYNOTE-B61 resulted in narrow confidence intervals and relatively reliable findings. The trial reported a median progression-free survival (PFS) of 18 months (95% CI, 14-not reached), with insufficient follow-up data to determine the median overall survival.
CA-209 9KU Trial Context
The CA-209 9KU trial (NCT03635892) was a single-center trial that enrolled 47 patients with non-ccRCC. While the combination investigated in CA-209 9KU, nivolumab (Opdivo) and cabozantinib (Cabometyx), is familiar to many oncologists and may be a first-line treatment choice for patients with clear cell RCC, the strength of evidence from CA-209 9KU is limited due to its noncomparative design and small sample size. Data from rarer non-ccRCC subtypes, such as chromophobe RCC, were not consistently reported in subsequent updates.
Treatment Paradigm
According to Thomas Westbrook, MD, assistant professor, Department of Internal Medicine, Rush University, the KEYNOTE-B61 regimen has emerged as a preferred non-ccRCC treatment option for many oncologists, although nivolumab plus cabozantinib may also be considered. Cross-trial comparisons between CA-209 9KU and KEYNOTE-B61 are unreliable due to differences in the trials’ baseline patient populations. However, the KEYNOTE-B61 regimen has emerged as a preferred non-ccRCC treatment option for many oncologists.
