A phase 2b, Randomized, double blinded comparison of the safety and efficacy of the monoclonal antibody mixture SYN023 and human rabies immune globulin in patients exposed to rabies
Publication Date
1-1-2024
Document Type
Article
Publication Title
Vaccine
Abstract
Background: SYN023 is an anti-rabies monoclonal antibody mixture administered as part of post-exposure prophylaxis regimens. The rabies virus neutralizing antibody (RVNA) concentration generally accepted as an adequate immune response to vaccination is ≥ 0.5 IU/mL. Methods: Within 54 h of potential rabies exposure, 448 patients in two risk substrata of WHO Category III exposure were randomized to receive either 0.3 mg/kg SYN023 or 0.133 mL/kg human rabies immunoglobulin (HRIG) injected in and around the wound site(s) plus a course of rabies vaccination. Patients were followed for safety and absence of rabies for ≥ 365 days. Results: GMT RVNA was higher with SYN023 throughout the 2-week post-treatment period. In the primary analysis group (n = 368), 99.4 % of SYN023 recipients versus 4.5 % of HRIG recipients had protective RVNA levels on Day 4. On Day 8, 98.1 % SYN023 versus 12.2 % HRIG recipients were protected. The SYN023:HRIG ratio of geometric mean titer of RVNA (RVNA GMTs) on Day 8 (19.42) exceeded the 10 % superiority margin (P < 0.0001) indicating higher Day 8 RVNA with SYN023. On Day 99, the SYN023:HRIG RVNA GMT ratio (0.66) was below the non-inferiority margin of 20 % (P = 0.9485) suggesting some moderation of vaccine immune response by SYN023 relative to HRIG. The ratio of percent SYN023:HRIG recipients achieving RVNA ≥ 0.5 IU/mL on Day 99 (0.98) met the non-inferiority margin of 20 % (P = 0.013) indicating anti-rabies immune response with SYN023 was non-inferior to HRIG despite this effect. There were no probable/confirmed rabies cases in any patient. Study regimens were well tolerated. Conclusions: SYN023 provided higher RVNA than HRIG soon after rabies exposure. By Day 99 post-treatment, GM RVNA with SYN023 was lower than HRIG, however, the percent of SYN023 recipients with a protective response was not inferior at this time point. No rabies cases were reported in the study. The SYN023 safety profile was acceptable. ClinicalTrials.gov ID: NCT03961555.
APA Citation
Quiambao, B.,
Payumo, R.,
Roa, C.,
Borja-Tabora, C.,
Emmeline Montellano, M.,
Reyes, M.,
Zoleta-De Jesus, L.,
Capeding, M.,
Solimen, D.,
Barez, M.,
Reid, C.,
Chuang, A.,
Tsao, E.,
&
McClain, J.
(1-1-2024).
A phase 2b, Randomized, double blinded comparison of the safety and efficacy of the monoclonal antibody mixture SYN023 and human rabies immune globulin in patients exposed to rabies.
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DOI:10.1016/j.vaccine.2024.05.066