The Phase I part of the study consists of a staggered inclusion of subjects in two cohorts of 3, to confirm the safety of the intended dose (320 µg RNA per antigen), with a lower dose to be considered in case of dose-limiting toxicity (DLT) being reported in greater than or equal to 2 out of 3-6 subjects; in this way, the recommended dose (RD) for the Phase IIa part of the study will be established. In the Phase IIa part of the study, additional subjects will be included at the RD, to confirm the safety and explore the activity of that dose.