A Phase IIa Study of Vitamin D3 Tolerogenic Dendritic Cells (tolDC) for Multiple Sclerosis

The investigators propose to design and conduct a phase IIa clinical trial to treat patients with progressive forms of multiple sclerosis (MS) by vaccination with tolerogenic dendritic cells (tolDC), generated using Good Manufacturing Practices (GMP). Hereby, the investigators want to demonstrate the efficacy and safety of administrating clinical-grade vitamin D3-treated tolDC loaded with myelin-derived peptides to patients with progressive forms of MS. In vitro generation of dedicated and stable immunomodulatory DC followed by in vitro loading of antigens to ensure tolerance and safety of DC-directed therapy is a promising strategy with the potential to induce long term tolerance.

This is an open-label, self-controlled, multi-center phase IIa clinical trial designed to evaluate the proof-of-concept for both efficacy and safety of tolDC-based therapy. The primary objective is to determine whether treatment with tolDC is effective (using a surrogate primary outcome-change in EDSS score) and safe (the occurrence and severity of adverse events). Secondary evaluations will include the clinical outcomes (assessed using 9HPT, SDMT and number and severity of relapses) and MRI-based markers. Participants will serve as their own controls, with data from 24 weeks pre-treatment period (documented by their neurologist). Following six tolDC administrations, a 24-weeks follow-period will take place. Furthermore, participants can enroll voluntarily into an optional additional follow-up phase of 52 weeks. Completion of screening assessments and confirmation of eligibility criteria should take no longer than 8 weeks.