The standard of care for locoregional clear-cell renal cell carcinoma (RCC) is partial or radical nephrectomy, despite nearly half of patients eventually experiencing recurrence and distant metastasis after surgery. Additionally, no adjuvant therapy has been globally accepted and guidelines only recommend active surveillance or entry into a clinical trial. [1,2]
Angiogenesis has a known role in RCC, therefore vascular endothelial growth factor (VEGF) inhibitors, sorafenib and sunitinib, were evaluated against each other and a placebo control in the phase III ASSURE trial for patients who had kidney cancer that has been removed by surgery, but they failed to substantially improve disease-free survival.  Contradictorily, sunitinib, a VEGF inhibitor, was found to provide significant improvement in disease-free survival versus placebo in the S-TRAC trial for patients at high risk of recurrence of RCC, subsequently leading to approval for use in the US.  Despite the positive results in S-TRAC, the conflicting conclusions of the two trials and the toxicity profile of the treatment have kept sunitinib from being approved in the European Union, and have not solved the need for better therapy options in RCC. It is hypothesized that the differences, in part, could be due patient selection because the staging viewpoint inclusion criteria was different between the two trials. 
Immunotherapy a cancer treatment that harnesses the immune system fight cancer, with the most popular being immune checkpoint inhibitors (ICIs). In particular, the ICIs targeting anti-programmed death (PD-1) antibodies, such as pembrolizumab, have demonstrated activity as both monotherapy and combination therapy for renal cell carcinoma. [6-11] Therefore, the KEYNOTE-564 trial evaluated whether pembrolizumab after nephrectomy improved clinical outcomes in patients with intermediate to high-risk of recurrence, with the first interim analysis recently published in The New England Journal of Medicine.  Patients enrolled in the trial had histologically confirmed locoregional RCC with a clear-cell component and met protocol-defined criteria for high-risk recurrence. They could not have received previous systemic therapy for RCC and had to have undergone surgery with negative surgical margins within 12 weeks before randomization. A total of 994 patients were randomized 1:1 to receive pembrolizumab or placebo after nephrectomy, with or without metastasectomy.
109 events of disease recurrence or death occurred in the pembrolizumab group compared to 151 in the placebo group. There was a 32% lower risk of disease recurrence or death in the pembrolizumab group than with placebo (hazard ratio for recurrence or death, 0.68; 95% confidence interval [CI], 0.53 to 0.87; P=0.002 [two-sided]). At 24 months the estimated percentage of patients who were alive was 77.3% (95% CI, 72.8 to 81.1) in the pembrolizumab group and 68.1% (95% CI, 63.5 to 72.2) in the placebo group. The median disease-free survival was not reached in either group at the data cut-off date.
96.3% of the patients who received pembrolizumab had at least one adverse event of any grade or cause compared to 91.1% of those who received the placebo. In terms of severe events, 32.4% of patients treated with pembrolizumab and 17.7% of patients given the placebo had a grade 3 to 5 adverse event. The most common adverse event in both groups was fatigue followed by diarrhea, pruritus, and arthralgia. For patient reported outcomes, change from baseline to week 52 in the FKSI-DRS score was −1.12 (95% CI, −1.53 to −0.71) in the pembrolizumab group and −0.45 (95% CI, −0.84 to −0.05) in the placebo group. For the EORTC QLQ-C30 physical functioning score, the change from baseline was −1.81 (95% CI, −3.19 to −0.43) in the pembrolizumab group and −0.90 (95% CI, −2.23 to 0.44) in the placebo group. The scores were stable over time and not significantly different between groups.
The authors suggest that the preliminary results of the study indicate that the use of pembrolizumab as adjuvant immunotherapy might become a new standard of care in patients with RCC that is intermediate to high-risk of recurrence. The results from the longer follow-up at the next prespecified analysis timepoint should help further determine the effect of overall survival.
The success of immunotherapy has led to the use of checkpoint inhibitors in multiple tumor types. At MEDSIR we are also evaluating checkpoint inhibitors in our PECATI trial for thymic cancer and our ATRACTIB trial for breast cancer. For more information about our immunotherapy trials or if you want to be connected with our network of investigators, contact us!
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