Efficacy and safety of cabozantinib in metastatic renal cell carcinoma patients: Russian multicenter observational study

Abstract

Purpose: an assessment of efficacy and safety of cabozantinib in unselected patients with metastatic renal cell carcinoma in the first and subsequent lines of therapy.Materials and methods. Russian multicenter observational study included 92 consecutive patients with morphologically verified metastatic renal cell carcinoma treated with cabozantinib (60 mg/d) in 16 Russian centers. Median age of the patients was 56 (19-79) years, a male-to-female ratio - 3:1. At the start of cabozantinib therapy 27.2 % of patients had ECOG PS 2. Most common histological type of kidney cancer was clear-cell RCC (90.2 %). Most patients were diagnosed with synchronous (71.7 %) multiple metastases (60.9 %). Previous nephrectomy was performed in 87.0 % of cases. Prognosis according to International Metastatic Renal Cancer Database Consortium (IMDC) score was assessed as favorable in 5.4 %, intermediate - in 58.7 % and poor - in 35.9 % patients. Cabozantinib as the first-line therapy was administered in 9 (9.8 %), following 1-5 lines of systemic treatment - in 83 (90.2 %) cases. Median follow-up was 11 (2.3-44.5) months.Results. In patients, receiving cabozantinib as the first-line therapy, objective response rate was 66.7 %, tumor control was reached in 100 % of cases. Median time to the objective response was 2.6 (1.9-3.6) months, median objective response duration - 13.2 (6.2-21.5) months. Median progression-free survival (PFS) and overall survival (OS) were not reached, 6- and 12-months PFS was 77.8 % and 77.8 %, 6- and 12-months OS - 88.9 % and 88.9 % respectively. Cabozantinib as the second and subsequent lines of therapy provided objective response rate of 34.9 %, tumor control rate - 97.6     %. Median time to the objective response was 2.5 (1.8-4.1) months, median objective response duration - 12.6 (5.5-27.3) months. Median PFS was not reached (6- and 12-months PFS - 92.5 % and 73.1 % respectively), median OS was 32.6      months (6- and 12-months OS - 97.4 % and 80.8 % respectively). Any adverse events (AE) developed in 88.8 %, AE grade III-IV - in 32.6 % of cases. Most frequent AE grade III-IV included arterial hypertension (18.5 %), diarrhea (6.5 %) and palmar-plantar erythrodysesthesia (6.5 %). Unacceptable toxicity demanded treatment cancellation in 2.2 %, therapy interruption - in 16.3 % and dose reduction - in 30.4 % of patients.Conclusion. Cabozantinib as the first and subsequent lines of therapy for metastatic renal cell carcinoma patients in the real world practice demonstrated high efficacy and better tolerability comparing with population assigned for cabozantinib monotherapy in the randomized phase II-III trials.