 4. Untreated brain metastasises that may be considered active. Patients with previously treated brain metastases may participate provided they are stable i.e., without evidence of progression by imaging for at least 6 weeks prior to the first dose of study treatment, and any neurologic symptoms have returned to baseline, and there is no evidence of new or enlarging brain metastases, and the patient does not require any systemic corticosteroids for management of brain metastases within 4 weeks prior to the first dose of REGN2810 certain exceptions may apply. 