Avelumab Plus Intermittent Axitinib in Previously Untreated Patients with Metastatic Renal Cell Carcinoma. The Tide-A Phase 2 Study

Background: Combinations of vascular endothelial growth factor receptor (VEGFR) tyrosine kinase inhibitors (TKIs) plus immune checkpoint inhibitor (ICI) against PD1/PD-L1 are the standard first-line therapy for patients with metastatic renal cell carcinoma (mRCC), irrespective of the prognostic class. Objective: To investigate the feasibility and safety of withdrawing VEGFR-TKI but continuing anti-PD1/PD-L1 in patients who achieve a response to their combination. Design, setting, and participants: This was a single-arm phase 2 trial in patients with treatment-naïve mRCC with prior nephrectomy, without symptomatic/bulky disease and no liver metastases. Intervention: Enrolled patients received axitinib + avelumab; after 36 wk of therapy those who achieved a tumour response interrupted axitinib and continued avelumab maintenance until disease progression. Outcome measurements and statistical analysis: The primary endpoint was the rate of patients without progression 8 wk after the axitinib interruption. The secondary endpoints were the median value for progression-free (mPFS) and overall (mOS) survival and the safety in the overall population. Results and limitations: Seventy-nine patients were enrolled and 75 were evaluated for efficacy. A total of 29 (38%) patients had axitinib withdrawn, as per the study design, with 72% of them having no progression after 8 wk and thus achieving the primary endpoint. The mPFS of the overall population was 24 mo, while the mOS was not reached. The objective response rate was 76% (12% complete response and 64% partial response), with 19% of patients having stable disease. In the patients who discontinued axitinib, the incidence of adverse events of any grade was 59% for grade 3 and 3% for grade 4. This study was limited by the lack of a comparative arm. Conclusions: The TIDE-A study demonstrates that the withdrawal of VEGFR-TKI with ICI maintenance is feasible for selected mRCC patients with evidence of a response to the VEGFR-TKI + ICI combination employed in first-line therapy. Axitinib interruption with avelumab maintenance leads to decreased side effects and should be investigated further as a new strategy to delay tumour progression. Patient summary: We evaluated whether certain patients with advanced kidney cancer treated with the fist-line combination of axitinib plus avelumab can interrupt the axitinib in case of a tumour response after 36 wk of therapy. We found that axitinib interruption improved the safety of the combination, while the maintenance with avelumab might delay tumour progression.