Axitinib is an orally bioavailable tyrosine kinase inhibitor currently approved in EU for treatment of patients affected by metastatic renal cell carcinoma (mRCC) progressed after another anti VEGFR-tyrosine kinase inhibitor (TKI).~Axitinib inhibits the proangiogenic cytokines vascular endothelial growth factor (VEGF) and platelet-derived growth factor receptor (PDGF), thereby exerting an anti-angiogenic effect.~Avelumab is a human immunoglobulin G1 (IgG1) monoclonal antibody directed against the human immunosuppressive ligand programmed death-ligand 1 (PD-L1) protein, with potential immune checkpoint inhibitory and antineoplastic activities. Upon administration, avelumab binds to PD-L1 and prevents the interaction of PD-L1 with its receptor programmed cell death protein 1 (PD-1). This inhibits the activation of PD-1 and its downstream signaling pathways. This may restore immune function through the activation of cytotoxic T lymphocytes (CTLs) targeted to PD-L1-overexpressing tumor cells. In addition, avelumab induces an antibody-dependent cellular cytotoxic (ADCC) response against PD-L1-expressing tumor cells. PD-1, a cell surface receptor belonging to the immunoglobulin superfamily expressed on T cells, negatively regulates T-cell activation and effector function when activated by its ligand, and plays an important role in tumor evasion from host immunity. PD-L1, a transmembrane protein, is overexpressed on a variety of tumor cell types and is associated with poor prognosis.~The combination of axitinib plus avelumab has been recently reported to be better than sunitinib alone for treatment of previously untreated mRCC patients (Motzer RJ, et al. NEJM 2019). The study reported a median PFS of 13.8 for the combination of axitinib plus avelumab compared to 8.4 months for sunitinib (p<0.001).~To improve the treatment related toxicity, a previous study suggests that the discontinuation of the TKI in patients achieving a tumor response may lead to a longer definitive progression free survival (22.4 months) and overall survival (34.8 months) with a better safety profile (Ornstein MC et al. JCO 2017). Despite the new response to TKI after its reintroduction, the majority of patients progressed after the first months of treatment discontinuation suggesting the necessity to maintain the tumor response.~This study aims to test if patients achieving a tumor response with the combination of axitinib plus avelumab, can discontinued the axitinib in order to delay the resistance to the anti VEGFR-TKI and decrease the related toxicity of the combination therapy.~This is a phase II trial with a partial treatment discontinuation design in patients who achieved tumor decrease greater than 30% compared to baseline during the first 36 weeks of therapy.~All patients enrolled in the trail will receive axitinib at 5 mg BID plus avelumab at 10 mg/Kg every two weeks.~Treatment will be continued until progression of disease during the first 36 weeks of therapy. At week 36, patients achieving a tumor decrease ≥ 30% will discontinue axitinib and continue avelumab until progression of disease defined as ≥ 20% increase compared to the tumor burden measured at week 36. At disease progression, axitinib will be restarted at the same dosage used before discontinuation for at least 24 weeks if progression did not occur before. Patients who achieved again tumor decrease of ≥ 30% after 24 weeks of therapy rechallenge with axitinib and avelumab may discontinue axitinib and maintain avelumab until progression of disease in an intermittent manner.
This study aims to test if patients achieving a tumor response with the combination of axitinib plus avelumab, can discontinued the axitinib in order to delay the resistance to the anti VEGFR-TKI and decrease the related toxicity of the combination therapy.