Critères d'inclusion : - Woman older than 18 years
- Patients with gestational trophoblastic disease resistant to mono-chemotherapy (methotrexate and/or actinomycine-D) or polychemotherapy (such as EMA-CO; EMA-EP; BEP; … regimens) without limitation in the number of previous chemotherapy lines
- Patients with Eastern Cooperative Oncology Group (ECOG) performance status ≤ 2
- Patients with adequate bone marrow function measured within 28 days prior to administration of study treatment as defined below : Absolute granulocyte count ≥ 1.5 x 10 9 /L ; Platelet count ≥ 100 x 10 9 /L ; Haemoglobin ≥ 9.0 g/dL (may have been blood transfused)
- Patients with adequate renal function : Calculated creatinine clearance ≥ 30 ml/min according to the Cockcroft-Gault formula (or local institutional standard method)
- Patients with adequate hepatic function : Serum bilirubin ≤ 1.5 x UNL and AST/ALT ≤ 2.5 X UNL (≤ 5 X UNL for patients with liver metastases)
- Patients must have a life expectancy ≥ 16 weeks
- Confirmation by a gynecologist of non-childbearing status for women of childbearing potential.
An evolutive pregnancy can be ruled out in the following cases: previous hysterectomy ; if serum hCG level ≥ 2 000 IU/L and no intra or extra-uterine gestational sac is detected on pelvic ultrasound ; if serum hCG level < 2 000 IU/L on a first measurement and serum hCG increases <100% on a second measurement performed 3 days later.
- Highly effective contraception if the risk of conception exists. (Note: The effects of the trial drug on the developing human fetus are unknown; thus, women of childbearing potential must agree to use 2 highly effective contraceptions, defined as methods with a failure rate of less than 1 % per year. Highly effective contraception is required at least 28 days prior, throughout and for at least 60 days after avelumab treatment.
- Patients who gave its written informed consent to participate to the study
- Patients affiliated to a social insurance regime
- Patient is willing and able to comply with the protocol for the duration of the study including undergoing treatment and scheduled visits and examinations including follow up.
Critères de non-inclusion : - Prior therapy with an anti-PD-1, anti-PD-L1, anti-PD-L2, anti-CD137, or anti-cytotoxicT lymphocyte-associated antigen 4 (CTLA 4) antibody (including ipilimumab, tremelimumab or any other antibody or drug specifically targeting T-cell co-stimulation or immune checkpoint pathways).
- Illness, incompatible with avelumab, such as congestive heart failure; respiratory distress; liver failure; allergy.
- Patients with second primary cancer, except: adequately treated non-melanoma skin cancer, curatively treated in-situ cancer of the cervix, or other solid tumours curatively treated with no evidence of disease for ≥ 5 years.
- All subjects with brain metastases, except those meeting the following criteria: Brain metastases that have been treated locally and are clinically stable for at least 2 weeks prior to enrollment ; No ongoing neurological symptoms that are related to the brain localization of the disease (sequelae that are a consequence of the treatment of the brain metastases are acceptable) ; Subjects with brain metastases must be either off steroids except a stable or decreasing dose of <10mg daily prednisone (or equivalent).
- Patients receiving any systemic chemotherapy, radiotherapy (except for palliative reasons), within 2 weeks from the last dose prior to study treatment (or a longer period depending on the defined characteristics of the agents used). The patient can receive a stable dose of bisphosphonates for bone metastases, before and during the study as long as these were started at least 4 weeks prior to treatment with study drug.
- Persistent toxicities (>=CTCAE grade 2) with the exception of alopecia and sensory neuropathy, caused by previous cancer therapy.
- Treatment with other investigational agents.
- Bowel occlusive syndrome or other gastro-intestinal disorder that does not allow oral medication such as malabsorption.
- Known severe hypersensitivity reactions to monoclonal antibodies, any history of anaphylaxis, or uncontrolled asthma
- Known human immunodeficiency virus (HIV) or acquired immunodeficiency syndrome (AIDS) related illness.
- Active infection requiring systemic therapy.
- Positive test for HBV surface antigen and / or confirmatory HCV RNA (if anti-HCV antibody tested positive)
- Administration of a live vaccine within 30 days prior to study entry.
- Current or prior use of immunosuppressive medication within 7 days prior to start of study treatment. The following are exceptions to this exclusion criterion: Intranasal, inhaled, topical steroids, or local steroid injections (eg, intra-articular injection); Systemic corticosteroids at physiologic doses not to exceed 10 mg/day of prednisone or equivalent; Steroids as premedication for hypersensitivity reactions (eg, CT scan premedication).
- Active autoimmune disease that might deteriorate when receiving an immunostimulatory agents. Patients with diabetes type I, vitiligo, psoriasis, hypo- or hyperthyroid disease not requiring immunosuppressive treatment are eligible.
- Female patients who are pregnant or lactating, or are of childbearing potential and not practicing a medically acceptable method of birth control.
Treatment with oral anticoagulant such Coumadin.