Denosumab and pembrolizumab in clear cell renal carcinoma (KEYPAD): A phase II trial (ANZUP1601)

TPS367 Background: Inhibitors of the programmed death-1 pathway (PD-1) are effective in clear cell renal cell cancer (ccRCC). Preclinical data and case reports suggest that denosumab, an inhibitor of Receptor Activator of Nuclear Factor κ-B Ligand (RANKL) signaling, could potentiate the anti-tumour effects of anti-PD1 inhibitors without overlapping toxicities. We aim to determine the activity and safety of combining denosumab and pembrolizumab in advanced ccRCC. Methods: This single arm, multi-center, phase II trial will recruit 70 participants with metastatic or unresectable ccRCC, progressing during or after treatment with vascular endothelial growth factor receptor (VEGFR) tyrosine kinase inhibitors, and with no prior treatment with immunotherapy or denosumab. Participants will receive pembrolizumab 200mg IV every 3 weeks plus denosumab 120mg SC on days 1, 8 and 22 and then every 3 weeks until disease progression, prohibitive toxicity or maximum treatment of 24 months. Response will be assessed at weeks 12, 18, 24, then every 12 weeks until disease progression. Bloods for translational studies are collected at baseline, week 6 and on disease progression. The primary endpoint is objective tumour response rate (OTRR) per RECIST 1.1. Secondary endpoints include OTRR per iRECIST, progression free survival (PFS), time to OTRR, time to first skeletal related event, adverse events, and frequency of treatment delays/discontinuations. Correlative studies will include identification of prognostic and/or predictive biomarkers relating to immune and RANKL signaling. A sample size of 70 provides 90% power with a 1-sided type 1 error rate of 10% to distinguish the observed OTRR (and PFS at 6 months) from an OTRR of 40% (worthy of pursuit) versus 25% (not worthy of pursuit). 15 sites are open across Australia. As of September 23, 2020, 40 patients have been recruited. Clinical trial information: NCT03280667 .