mRNA Electroporated Autologous Dendritic Cells for Stage III/IV Melanoma

This is an open label, 2-arm, 1-stage, randomized controlled phase II study in patients with AJCC stage IIIB/C \& -IV melanoma. At baseline tumor assessment (using total body FDG-PET/CT), patients should be free from measurable tumor lesions (according to RECISTv1.1 definitions) following prior local therapy (e.g. following surgical resection, isolated limb perfusion, radiofrequency ablation, cryotherapy, radiotherapy, electrochemotherapy, …). Patients should not have symptomatic non-measurable tumor lesions (e.g. bone metastasis, or pleural effusion), and lesions treated by prior local therapy should be free from progression. Patients should not have received any prior systemic therapy (non-experimental or experimental). * Patients will be randomized between two treatment arms (Arm-A and -B). In study Arm-A, patients will receive DC-administrations during one year following randomization. Salvage treatment by local therapies will be allowed during the study treatment in Arm-A. In study Arm-B, patients will initiate DC-administrations only after documented recurrence of the melanoma that cannot be salvaged by local therapy. * The primary endpoint of this clinical trial is to determine the rate (%) of patients who are free from macrometastases (: measurable tumor lesions and symptomatic non-measurable tumor lesions) at 1-year (= 52 weeks) after randomization. Patients treated on Arm-B will serve as a contemporary control-arm to help interpreting the outcome of patients treated in Arm-A. By design (phase II) this trial will not be powered to statistically prove a predefined difference between the two study arms (this would require a phase III design). Patients treated in Arm-B will be able to initiate immunotherapy with autologous DC at the time of recurrence that can not be salvaged by local therapy. Documentation of the anti-tumor activity and survival following DC-treatment at recurrence in Arm-B patients will be a secondary objective of this clinical trial.