Proof-of-concept of a low-dose unmodified mRNA-based rabies vaccine formulated with lipid nanoparticles in human volunteers: A phase 1 trial.

INTRODUCTION: In a first-in-human study immune responses to rabies virus glycoprotein (RABV-G)-mRNA vaccine were dependent on the route of administration, necessitating specialized devices. Following successful preclinical studies with mRNA encapsulated in lipid nanoparticles (LNP), we tested an mRNA-LNP formulation (CV7202). METHODS: In this phase 1, multi-center, controlled study in Belgium and Germany we enrolled 55 healthy 18-40-year-olds to receive intramuscular injections of 5 µg (n = 10), 1 µg (n = 16), or 2 µg (n = 16) CV7202 on Day 1; subsets (n = 8) of 1 µg and 2 µg groups received second doses on Day 29. Controls (n = 10) received rabies vaccine, Rabipur, on Days 1, 8 and 29. Safety and reactogenicity were assessed up to 28 days post-vaccination using diary cards; immunogenicity was measured as RABV-G-specific neutralizing titers (VNT) by RFFIT and IgG by ELISA. RESULTS: As initially tested doses of 5 µg CV7202 elicited unacceptably high reactogenicity we subsequently tested 1 and 2 µg doses which were better tolerated. No vaccine-related serious adverse events or withdrawals occurred. Low, dose-dependent VNT responses were detectable from Day 15 and by Day 29%, 31% and 22% of 1, 2 and 5 µg groups, respectively, had VNTs ≥ 0·5 IU/mL, considered an adequate response by the WHO. After two 1 or 2 µg doses all recipients had titers ≥ 0.5 IU/mL by Day 43. Day 57 GMTs were not significantly lower than those with Rabipur, which elicited adequate responses in all vaccinees after two doses. CV7202-elicited VNT were significantly correlated with RABV-G-specific IgG antibodies (r2 = 0.8319, p < 0.0001). CONCLUSIONS: Two 1 µg or 2 µg doses of CV7202 were well tolerated and elicited rabies neutralizing antibody responses that met WHO criteria in all recipients, but 5 µg had unacceptable reactogenicity for a prophylactic vaccine. ClinicalTrials.gov Identifier: NCT03713086.

Establishing a reference interval for bone turnover markers in 637 healthy, young, premenopausal women from the United Kingdom, France, Belgium, and the United States.

Robust reference intervals are needed for the interpretation of bone turnover markers in large phase III fracture trials. The objectives of the study were to (1) estimate reference intervals for serum bone alkaline phosphatase (bone ALP), serum procollagen type I N propeptide (PINP), serum beta cross-linked C-telopeptides of type I collagen (S-betaCTX), and urinary cross-linked N-telopeptides of type I collagen (U-NTX) in healthy young premenopausal women; (2) examine geographical differences on bone turnover markers; and (3) assess factors known to influence bone turnover and test whether these explain any regional differences. We studied 637 eligible women from four countries that participated in the Horizon-PFT study (United Kingdom, France, Belgium, United States). The women were 30-39 yr of age (mean, 34.6 yr), with regular cyclic menses. Subjects completed a medical and lifestyle questionnaire. Two-sided 95% reference intervals were estimated on transformed values and transformed back to the original scale using the proposed methodology of the International Federation of Clinical Chemistry. S-betaCTX was significantly higher in France relative to the United Kingdom (p = 0.01), and PINP was higher in France (p < 0.001) and Belgium (p = 0.02) relative to the United Kingdom and significantly higher in France relative to the United States (p < 0.01) by ANOVA. Overall, one could associate low bone turnover markers with nonsmoking, use of a contraceptive pill, exercise, being close to the time of ovulation, and having high 25-hydroxyvitamin D levels. Countries differed by these characteristics, and once allowed for in the statistical model, any country differences were attenuated or removed.