• Patient ≥18 months old and ≤ 17 years old

• Relapsed or refractory Wilms tumor, histologically proven at diagnosis

• After at least 2 lines of chemotherapy (conventional or high dose, which may include the trial molecules) or after 1 line for high risk relapse for which there would not be any curative therapy. If 1 line for high risk relapse, the enrolment should be confirmed by coordinators.

• Radiologically measurable or evaluable disease (visible, target or non-target-lesion on MRI or CT-scan)

• Performance status: Karnofsky performance status (for patients \>16 years of age) or Lansky Play score (for patients ≤16 years of age) ≥ 70%.

• Able to take oral medication or nasal gastric tube or authorized gastrostomy

• Adequate biological criteria:

‣ Neutrophils \> 1000/mm3 ; Platelets \> 75 000/mm3

⁃ Transaminases (ALT/ AST) ≤ 3 times ULN (or ≤ 6 times ULN if liver metastasis); total bilirubin ≤ 2 ULN (except in case of Gilbert's disease)

• Creatinine ≤ 1,5 ULN or clearance ≥ 60 mL/ min/ 1,73m2 (In case of doubt, to be confirm by assessment of cystatin )

• Females of childbearing potential must have a negative seric pregnancy test within 7 days prior to initiation of treatment.

• Sexually active patients must agree to use adequate and appropriate contraception (at least one highly effective contraception or two complementary methods of contraception), 1 month before beginning of treatment while on trial drug and for 7 months after stopping the trial drug for female patients and after 6 months for male patients.

• Written informed consent from parents/legal representative, patient, and age-appropriate assent before any trial-specific screening procedures according to national guidelines.

• Patient covered by the French Social Security regime