Pilot Study of Cabozantinib Efficacy, Safety and Tolerability in Metastatic Renal Carcinoma in Aged Fragile Patients: CABOMAYOR Study

Aged fragile patients are not usually included in clinical trials and efficacy and tolerability of the different available treatments in this population are unknown. Conversely, ageing has been associated with a decrease in the efficacy of immune checkpoint inhibitors due to a decline in the effectiveness of the immune system (immunosenescence). In the Checkmate 025 trial comparing nivolumab with everolimus, the Hazard Ratio (HR) in patients older than 75 years old favoured everolimus, 1.23 (0.66-2.31). Thus, TKis might be a better treatment option for this population. However, the absence of data and concerns about possible secondary effects associated, can preclude clinicians to treat aged fragile patients with cabozantinib. A pilot phase II trial would help to have data on safety and efficacy of cabozantinib in this aged fragile population. In METEOR trial around 60% of patients reduced the dose of cabozantinib because of toxicity and tolerance problems. It is suspected that the efficacy of cabozantinib in the population to be included in this trial (aged and fragile) will be similar to that observed in CABOSUN trial (disease control rate around 75%). However, there is no information available in this group of patients. On the other hand, in the \>75 years old subgroup within the METEOR trial, 37% discontinued due to adverse events, 85% needed dose reductions and median average daily dose was 33,6 mg. For this reason, the cabozantinib initial dose chosen for patients to be included in this study is 40 mg/day.