Anti PD-1 monoclonal antibodies (nivolumab and pembrolizumab) alone or in association with antiCTLA4 (Ipilimumab) are established as indisputable treatment of metastatic melanoma, with unprecedented overall survival, and are indicated for first-line treatment including patients with BRAF mutation. Given their high molecular weight, their penetration in the brain sanctuary is uncertain and relies on disruption of the Blood Brain Barrier (BBB) which occurs occasionally.

SonoCloud® is an implantable device delivering low intensity pulsed UltraSound (US). Along with systemic injection of an US resonator, SonoCloud® demonstrated safe and efficient at repetitively opening the BBB. The investigators anticipate that BBB opening could help at increasing brain penetration of monoclonal antibodies and potentially boosting immunity in the brain. This could translate in controlling brain disease with the same magnitude as for extra-cranial disease. This would also open avenues for optimizing the treatment of brain metastases in combination with checkpoint inhibitors in many other cancers.

Inclusion Criteria:

• Patients with histologically confirmed metastatic melanoma
• Patients must have recovered from all side effects of their most recent systemic or local treatment for metastatic melanoma (grade ≤ 1).
• At least one measurable brain metastasis between 5 mm and 35 mm in diameter, not previously treated with surgery and/or radiosurgery and located less than 5 cm from the skull
• Patients may have received -or not- prior radiosurgery and/or surgery for brain metastases; if they have received prior local treatment, they must have at least 1new RANO and RECIST assessable brain metastases.
• BRAF status wild type or mutated (and in that case previous treatment with BRAF inhibitor and MEK inhibitor allowed)
• Eastern Cooperative Oncology Group (ECOG) performance status (PS) ≤ 1.
• Age >18 year
• Hemoglobin ≥10g/dl
• Platelets ≥ 100000mm3
• Neutrophils ≥1500/mm3
• Creatinine Clearance ≥ 50ml/mn
• AST <3N
• ALT<3N
• Total bilirubin <1.5N
• Alkaline phosphatase <3N
• INR < 1.5
• Prothrombin ≥70%
• TCA <1.2
• No Hepatocellular insufficiency
• No unhealed wound on the head
• No allergy to poly isoprene
• Signed informed consent
• Patient with health insurance coverage
• Life expectancy > 3 months

Exclusion Criteria:

• Patient previously treated by antiPD1 (except adjuvant antiPD1 therapy)
• Ocular melanoma
• Symptomatic or diffuse leptomeningeal involvement.
• Symptomatic hemorrhagic brain metastases.
• Symptoms of incoercible intracranial pressure; patients receiving corticosteroids and patients presenting intermittent seizures can be enrolled if they have a stable dose of corticosteroids (≤ 30mg/day corticotherapy) and anti-epileptic treatment since at least 2 weeks before enrolment.
• Indication for urgent neurosurgery or radiotherapy
• Prior malignancy active within the previous 2 years except for locally curable cancers that have been apparently cured or stage I untreated Chronic Lymphoid Leukemia.
• Known human immunodeficiency viruses (HIV) infection and any ongoing infectious disease or significant background.
• Concurrent administration of any anticancer therapies other than those administered in this study.
• Treatment with any cytotoxic and/or investigational drug, antiCTLA4 or targeted therapy ≤ 4 weeks or <5 half lives for targeted therapies or chemotherapy, prior to day 1 of study.
• Prior whole brain radiotherapy