The study of the blood concentration of ITK what are pazopanib and cabozantinib at 1 month and 3 months from the start of treatment will allow to evaluate the impact of renal failure on their efficacy and toxicity in patients with metastatic kidney cancer.

This study involves patients treated with cabozantinib or pazopanib in their metastatic renal cancer.

Indeed, the aim of this study is to assess the blood concentration of these two drugs as well as their tolerance, in relation to their renal function (normal renal function or moderate or severe renal failure).

Pazopanib and cabozantinib are kinase inhibitors that are indicated for a number of cancer conditions, including metastatic kidney cancer.

Both of these oral therapies require a daily intake of the drug to ensure its effectiveness.

For this, the patient must have optimal compliance and benefit from regular follow up to assess clinical and biological tolerance.

Chronic renal failure is a factor that may impact the efficacy and toxicity of pazopanib and cabozantinib. This may be due either to a elimination default of the drug or to much elimination if the drug is filtered after dialysis.

As a result, kinase inhibitors could be impacted by chronic renal failure and thus modify the safety and efficacy of the treatment.

A study-specific blood test will be taken at 1 month and at 3 months during a consultation (this blood test is in addition to the routine blood test). Its analysis will evaluate the quantity of medication present in the blood.

The other objective of this study is to evaluate the side effects of the drug taken by the patient (pazopanib or cabozantinib).

This will alow to propose possible dose adjustments for each of these treatments and thus improve the management of these patients.

Inclusion Criteria:

1. Patient followed for metastatic clear cell renal cell carcinoma.
2. Age ≥18 years old.
3. Performance Status (PS) according to Eastern Cooperative Oncology Group (ECOG) = 0, 1 or 2
4. Patient treated with a VEGF-R inhibitor: pazopanib or cabozantinib for metastatic kidney cancer.
5. If patient doesn't have renal failure -> group 1, or if patient has chronic renal failure according to the moderate stage Chronic Kidney Disease - Epidemiology (CKD-EPI) formula (Clr <60 ml / min, stage 3) -> group 2, or if patient have chronic renal failure according to the CKD-EPI formula of severe or terminal stage (Clr <30 ml / min, stage 4 and stage 5), with or without dialysis -> group 3.
6. Willingness and ability to comply with scheduled visits, treatment plan, laboratory tests and other study procedures.
7. Patient having given informed, written and express consent.
8. Affiliation to the French Social Security System.

Exclusion Criteria:

1. Indication other than clear cell renal cell carcinoma for these same ITKs
2. Pregnant or breast-feeding subjects
3. Patient whose regular follow-up is impossible for psychological, family, social or geographic reasons,
4. Patient under guardianship, curatorship or safeguard of justice
5. Participation in another clinical study with a research product during the last 30 days before inclusion.

Individual Participant Data will not be shared at an individual level. Those data will be part of the study database including all enrolled patients.