In metastatic renal cell carcinoma (mRCC) the PD-1 immune-checkpoint inhibitor (ICI) Nivolumab became a standard second line treatment option in 2015 based on a significant improvement of overall survival compared to Everolimus. Current pivotal phase 3 studies showed that PD-1 ICI-based combinations were more efficacious than the VEGFR-TKI Sunitinib, a previous standard of care, leading to approval of three new regimens as guideline-recommended first-line treatment. Nivolumab plus Ipilimumab is characterized by a survival advantage, a high rate of complete response and durable remissions in intermediate and poor prognosis patients. Despite frequent immune-mediated side effects, fewer symptoms and a better quality of life were observed compared to Sunitinib. Pembrolizumab or Avelumab plus Axitinib were characterized by an improved progression-free-survival and a high response rate with a low rate of intrinsic resistance. In addition, Pembrolizumab plus Axitinib reached a significant survival benefit. The side effect profile is driven by the chronic toxicity of Axitinib, but there is additional risk of immune-mediated side effects of the PD-1/PD-L1 ICIs. The quality of life data published so far do not suggest any improvement regarding patient-reported outcomes compared to the previous standard Sunitinib. The PD-1/PD-L1 ICIs thus form the backbone of the first-line therapy of mRCC.

Immune checkpoint inhibitors (ICI) are now, among other cancers, routinely used for the treatment of advanced or metastatic renal cell carcinoma (mRCC). In mRCC various combinations of ICIs and inhibitors of the vascular epidermal growth factor receptor tyrosine kinase (VEGFR-TKIs) as well as dual checkpoint inhibition (nivolumab + ipilimumab), the latter for patients with intermediate and poor risk according to IMDC only (international metastatic renal cell carcinoma database consortium), are now standard of care in the first line setting. Therefore, a profound understanding of immune-related adverse events (irAE) and the differential diagnosis of adverse reactions caused by other therapeutic agents in combination therapies is of paramount importance. Here we describe prevention, early diagnosis and clinical management of the most relevant irAE derived from ICI treatment focusing on the new VEGFR-TKI/ICI combinations.

PURPOSE: Several anti–programmed cell death (ligand)-1 (PD-[L]1) immune checkpoint inhibitors are approved in advanced/metastatic urothelial carcinoma (mUC). Recently, improved activity of an anti–PD-1/anticytotoxic T-cell lymphocyte-4 (CTLA-4) combination versus anti–PD-1 monotherapy has been reported. We report a response-based approach starting treatment with nivolumab monotherapy with nivolumab/ipilimumab as immunotherapeutic boost. METHODS: After four doses of nivolumab induction, responders continued with nivolumab maintenance therapy. Patients with stable/progressive disease received nivolumab 3 mg/kg plus ipilimumab 1 mg/kg once every 3 weeks for 2 doses followed by nivolumab 1 mg/kg plus ipilimumab 3 mg/kg once every 3 weeks for 2 doses, if not responding to the initial boost. Responders to boosts continued with nivolumab maintenance. Between July 2017 and April 2019, 86 patients were enrolled. The median follow-up is 7.7 months. The primary end point is objective response rate (ORR) per RECIST1.1. Secondary end points include efficacy of nivolumab induction, remission rate with nivolumab/ipilimumab boosts, overall survival, and safety. RESULTS: Of all patients, 42, 39, and five were first- (1L), second- (2L), and third-line (3L), respectively. The median age was 68 years. The ORR with nivolumab monotherapy (assessed at week 8) was 29% in 1L and 23% in 2/3L, respectively. Forty-one patients received early (week 8) and 11 received later nivolumab/ipilimumab boosts. ORRs with nivolumab with or without nivolumab/ipilimumab (best overall response) were 45% and 27% in 1L and 2/3L, respectively. In 1L, 7 of 17 patients receiving boosts at week 8 improved, compared with 2 of 24 in 2/3L. CONCLUSION: The tailored approach of TITAN-TCC shows meaningful clinical activity supporting dual checkpoint inhibition in 1L mUC. However, starting therapy with nivolumab exclusively appears inadequate given the aggressive nature of mUC. In 2/3L, nivolumab/ipilimumab boosts with escalating ipilimumab dose did not improve efficacy outcomes versus nivolumab monotherapy. An independent 2L cohort of TITAN-TCC receiving nivolumab 1 mg/kg plus ipilimumab 3 mg/kg once every 3 weeks for 4 doses is ongoing.

Systemic therapy for metastatic renal cell carcinoma has continuously evolved over the last two decades. Significant improvements in overall survival and quality of life of patients with advanced disease have been observed. With the approval of combination therapies with PD(L)-1 immune checkpoint inhibitors (ICI) as first-line therapy in 2019, the previous standard VEGFR-TKI monotherapy has been replaced as the primary treatment option. In addition to immunotherapy with nivolumab and ipilimumab, three VEGFR-TKI/ICI combinations are now approved. Therapy selection should be preceded by risk stratification using defined criteria from the International Metastatic Renal Cell Carcinoma Database Consortium (IMDC). Clinical parameters, as well as detailed patient counseling on differences in the efficacy profile (response rate, long-term progression-free survival), potential side effects, and impact on quality of life, are of key importance in the individual treatment decision.