Nearly all patients (about 99% in each group) had an adverse event (AE). Hypertension was the most common side effect, with grade 3 or higher seen in 12.5% in the nivolumab plus cabzantinib group and 13.1% in the sunitinib group. Other grade 3 or higher side effects occurring in at least 10% of patients in any group were hyponatremia, diarrhea, palmar-plantar erythrodysesthesia, hypothyroidism, and fatigue. AEs of any cause leading to discontinuation of the therapy occurred in 19.7% in the nivolumab plus cabzantinib group vs 16.9% of the sunitinib group. One death was considered to be treatment-related (small intestinal perforation) in the nivolumab plus cabozantinib group vs 2 treatment-related deaths with sunitinib (pneumonia and respiratory distress). In the nivolumab plus cabozantinib group, 57% of the patients had a dose reduction of cabozantinib and 52% had a reduction in sunitinib dosage.
Using the Functional Assessment of Cancer Therapy-Kidney Symptoms Index, patients in the nivolumab plus cabozantinib group reported better health-related quality of life and less disease-related symptoms compared to the sunitinib group.
Commentary
The treatment landscape for frontline therapy for patients with advanced RCC has rapidly expanded over the last several years and has revolutionized cancer care. Ushered in by the results from the CheckMate 214 study highlighting the efficacy of dual checkpoint inhibition with nivolumab and ipilimumab in intermediate and poor risk patients, several subsequent trials have demonstrated improved outcomes with combination therapy with immune checkpoint inhibitors and tyrosine-kinase inhibitors (TKI). To date, data from Keynote-426 (pembrolizumab plus axitinib vs sunitinib), Javelin Renal 101 (avelumab plus axitinib vs sunitinib) and the CLEAR trial (lenvatinib plus pembrolizumab vs levatinib plus everolimus vs sunitinib) have demonstrated superiority of immune checkpoint inhibitor/TKI combinations over sunitinb in the first-line setting.1-5
The current phase 3, CheckMate 9ER trial adds yet another dynamic option for patients with advanced clear cell RCC. While cross-trial comparisons are fraught with important caveats, the median PFS of almost 16.6 months and complete response rate of 8% the nivolumab plus cabozantinib group compares favorably with other combinations. Data from the CLEAR study with the combination of lenvatinib and pembrolizumab showed a complete response rate approaching 16%. Importantly, the current study highlights improved quality of life with the combination of cabozantinib and nivolumab compared to sunitinib alone adding to the efficacy and benefits of this combination treatment.
The selection of first line therapy for patients with advanced RCC should be always guided by individual patient characteristics, and any single immune checkpoint inhibitor/TKI combination is not “superior” to any other. Perhaps more importantly is developing an understanding of the overlapping toxicity profiles of checkpoint inhibitors and TKIs. Again, this trial results are consistent with prior studies in terms of the adverse event profile which were not trivial, and almost all patients (99%) experienced AEs. It is important for oncologists to understand the management of the toxicities with these combinations and dose reductions as appropriate. It is worth noting that 19% of patients with nivolumab plus cabozantinib received glucocorticoids for management of immune-related AEs.
While long-term follow-up data will be needed to further understand the durability of response to this combination, nivolumab-cabozantinib represents an exciting new option for patients with advanced clear cell RCC. As we continue to see improvement in outcomes in clear cell histology, further work must focus on optimization of therapy in non-clear cell RCC as this is a population that is not represented in these data sets. Furthermore, future efforts should begin to explore triplet combinations and biomarker driven patient selection for upfront therapy in ordercontinue to improve outcomes in patients with advanced RCC.
Applications for Clinical Practice
The combination of nivolumab plus cabozantinib adds to the growing list of highly active checkpoint inhibitor/TKI combinations for first-line treatment of advanced RCC. With significant higher response rates, improved outcomes, and improvement in the quality of life, this combination will add another standard treatment option for patients with previously untreated advanced RCC.