Comparative Study of Two Vaccination Schedules for the Subunit Herpes Zoster Vaccine in Multiple Sclerosis and Neuromyelitis Optica Spectrum Disease Patients Treated With Anti-CD20 Therapy: an Open-label Randomised Controlled Trial

Shingles, caused by reactivation of varicella zoster virus (VZV), is a common condition in immunocompromised people. Its prevention, which has long remained a medical need unmet among these patients, was improved thanks to the availability of the recombinant glycoprotein-based VZV vaccine E (gE). Based on demonstrated clinical efficacy and safety profile in the general population as well as in immunocompromised patients, this vaccine is recommended in France according to a two-person schedule doses spaced two months apart in immunocompromised patients aged ≥ 18 years. However, further studies are needed in order to optimize vaccination strategies according to the different types of immunosuppression. Patients with MS or NMOSD, who are at increased risk of herpes zoster, are extensively treated with anti-CD20 monoclonal antibodies, which are known to significantly alter immune responses to vaccines, in particular when vaccination is carried out early after the infusion of anti-CD20. We hypothesize that in patients with MS or NMOSD treated with anti-CD20 administered every six months, a two-dose M0-M6 vaccination schedule, consisting of deferring the second dose to six months after the first, that is, five months after the anti-CD20 infusion, could improve vaccine immunogenicity and, consequently, the effectiveness of the vaccine. In this phase IV randomized, controlled, open-label, parallel-group trial, we will compare, within a homogeneous population of patients with MS or NMOSD receiving antiCD20, the humoral response induced by a two-dose vaccination schedule administered at 2 months (M0-M2, "2-month" or standard group) or 6 months (M0-M6, "6-month" or experimental group). After the screening and inclusion phase, patients randomized to the M0-M2 (standard) and M0-M6 (experimental) groups will receive a first dose of recombinant herpes zoster vaccine (RZV) one month before the next scheduled infusion of anti-CD20 monoclonal antibodies (M1). The second dose of RZV will be given at either 2 months ("2-month group", M2) or 6 months ("6-month group", M6). Patients will receive their usual anti-CD20 monoclonal antibody infusions at the appropriate time M1, M7 and M13. The primary outcome will be evaluated one month after the second vaccine dose (M3 for the "2 months" group and M7 for the "6 months" group). The kinetics, intensity, and persistence of humoral and cellular immune responses, as well as safety, will be analyzed as criteria for secondary judgments during the scheduled follow-up visits until M13.