This pilot study is an open-label interventional study, prospective, non-comparative, sequential (two stages), national, multicenter study.

Patients starting therapy with sunitinib or pazopanib as standard first line treatment for advanced or metastatic renal cell carcinoma will enter the study in one of the two cohorts (115 patients will be treated by sunitinib and 99 patients will be treated by pazopanib).

The purpose of this study is to examine the feasibility of sunitinib and pazopanib dose individualisation based on therapeutic drug monitoring (TDM) and to assess the benefit of this approach in terms of tolerance and efficacy compared with the current empirical method based only on tolerance observation.

Inclusion Criteria:

1. Patients starting therapy with sunitinib or pazopanib as standard first line treatment for advanced or metastatic renal cell carcinoma.
2. Measurable tumours as defined by RECIST criteria version 1.1.
3. Age ≥ 18 years old.
4. WHO Performance Status ≤ 2.
5. Life expectancy ≥ 6 months.
6. Adequate cardiac function (baseline Left Ventricular Ejection Fraction (LVEF) ≥ 50% determined by Multiple Gated Acquisition scan (MUGA) or echocardiography) and pulmonary function.
7. Renal function defined as creatinine clearance (Cockcroft and Gault formula) > 30 mL/min.
8. Adequate liver function defined as: total bilirubin ≤ 1.5 x Upper Limit of Normal (ULN); Alanine AminoTansferase (ALAT) and Aspartate AminoTransferase (ASAT) ≤ 2.5 x ULN; Concomitant elevation in bilirubin and ASAT/ALAT above 1.0 x ULN is not allowed.
9. Patients must provide written informed consent prior to performance of study-specific procedures or assessments, and must be willing to comply with treatment and follow-up.
10. Negative pregnancy test for women in childbearing potential.
11. Women of childbearing potential must be using an adequate method of contraception to avoid pregnancy throughout the study (before study entry and until 30 days after the last administration of study treatment).
12. Patients affiliated to a social health insurance.

Exclusion Criteria:

1. Patients without any venous access for blood sampling.

2. Hypersensitivity to the active substance or to any of the excipients.

3. History or clinical evidence of central nervous system (CNS) metastases, except for individuals who have previously-treated CNS metastases.

4. Corrected QT interval (QTc) > 480msecs using Bazett's formula.

5. Patients with other concurrent severe and/or uncontrolled medical disease which could compromise participation in the study, such as, but not limited to:

   • Uncontrolled infection.
   • Cardiovascular conditions within the last 6 months such as cardiac angioplasty or stenting, myocardial infarction, unstable angina, coronary artery bypass graft surgery, symptomatic peripheral vascular disease, Class III or IV congestive heart failure, as defined by the New-York Heart Association (NYHA), clinically significant irregular heartbeat requiring medication.
   • Poorly controlled hypertension [defined as systolic blood pressure of ≥140 mmHg or diastolic pressure of ≥90 mmHg).
   • History of cerebrovascular accident including transient ischemic attack (TIA), pulmonary embolism or deep venous thrombosis (DVT) within the past 6 months.

   Note: patients with recent DVT who have been treated with therapeutic anti-coagulating agents for at least 6 weeks are eligible.

6. Evidence of active bleeding or bleeding diathesis.

7. Patients being treated with drugs recognized as being strong inhibitors or inducers of the isoenzyme cytochrome P450 isoenzyme 3A4 (CYP3A4) within the last 14 days prior to inclusion and/or during the study.

8. Patients already treated with an anticancer treatment in the previous four weeks or patient requiring anticancer treatment during the study (chemotherapy, immunotherapy, hormonotherapy, radiotherapy or surgery).

9. Pregnant or breast-feeding women.

10. Positive diagnostic of HIV, B and C hepatitis.

11. Patients with serious and/or unstable pre-existing medical, psychiatric, or other condition that could interfere with patient's safety, provision of informed consent, or compliance to study procedures.

12. Patients who has forfeited his/her freedom by administrative or legal award or who is under guardianship.](streamdown:incomplete-link)