Trial to Evaluate the Immunogenicity of Dose Reduction Strategies of the MVA-BN Monkeypox Vaccine

Plain-language summary

This study is a Phase 2 randomized, open-label, non-placebo controlled, multi-site clinical trial that will evaluate two intradermal (ID) regimens for Modified Vaccinia Ankara-Bavarian Nordic (MVA-BN) vaccine compared to the standard subcutaneous (SC) regimen in healthy, vaccinia-naïve adults 18 to 50 years of age, inclusive. At least 210 participants will be enrolled and randomized to one of three study arms. The two dose sparing strategies include one-fifth (2 x 10\^7) and one-tenth (1 x 10\^7) of the standard dose of MVA-BN administered ID on Day 1 and 29 (Arm 1 and 2, respectively). The comparator arm (Arm 3) will be the 2-dose standard (1 x 10\^8) MVA-BN SC regimen. The study will enroll a 1:1:1 randomization allocation. Participants will not be stratified by clinical trial site, demographic characteristics or human immunodeficiency virus (HIV) infection status; however, these data will be collected during screening and enrollment. Each participant may be screened either in a separate visit in the 7 days prior to Day 1 or on Day 1. The primary hypothesis involves a two-step hierarchical process. The study will first test non-inferiority of the 2 x 10\^7 ID regimen relative to 1 x 10\^8 SC (standard dose regimen). If the 2 x 10\^7 ID regimen is non-inferior to the standard dose regimen, hypothesis testing will proceed to test non-inferiority of the 1 x 10\^7 ID regimen relative to the standard dose regimen. The primary objectives are: 1) to determine if peak humoral immune responses following an ID regimen of 2 x 10\^7 50% Tissue Culture Infectious Dose (TCID50) MVA-BN are non-inferior to the licensed regimen of 1 x 10\^8 MVA-BN administered SC; 2) to determine if peak humoral immune responses following an ID regimen of 1 x 10\^7 TCID50 MVA-BN are non-inferior to the licensed regimen of 1 x 10\^8 MVA-BN administered SC.

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Trial details