VAXCHORA Rx

Efficacy Against V. cholerae Challenge 

• Study 2 

• The efficacy of Vaxchora was evaluated in a randomized, double-blind, placebo-controlled human challenge study (n=197) of US volunteers aged 18–45 years old. Of the total volunteers, 68 Vaxchora recipients and 66 placebo recipients were challenged by oral ingestion of Vibrio cholerae. The efficacy of Vaxchora was 90.3% (95% CI, 62.7-100) among those challenged 10 days post-vaccination, and 79.5% (95% CI, 49.9-100) among those challenged 3 months post-vaccination. 

Immunogenicity 

Vibriocidal Antibody Against the Vaccine Strain (classical Inaba)  

• A vibriocidal antibody assay was used to measure serum levels of neutralizing antibodies against the vaccine strain.

• Study 2 

• In the subset of subjects challenged in Study 2, 91% [95% CI, 82%-97%] of vaccinees seroconverted prior to challenge and 9% developed moderate to severe cholera following challenge, while 2% of placebo recipients seroconverted prior to challenge and 59% developed moderate to severe cholera following challenge.  

• Study 1 

• Vaxchora was evaluated in the randomized, double-blind, placebo-controlled safety and immunogenicity study conducted in the US and Australia. A total of 3146 patients 18 to 45 years of age who were not previously exposed to cholera were randomly assigned 8:1 to receive one dose of Vaxchora or placebo. The classical Inaba vibriocidal antibody seroconversion rates were 93.5% (95% CI, 92.5%-94.4%] in vaccine recipients and 4% (95% CI, 2%-7%) in placebo recipients at 10 days post-vaccination.

• Study 4 

• The safety and immunogenicity of Vaxchora was evaluated in a randomized, double-blind, placebo-controlled study conducted in the US. A total of 398 patients 46 to 64 years of age with no prior history of cholera infection or travel to a cholera-endemic era in the previous 5 years were randomly assigned 3:1 to receive one dose of Vaxchora or placebo. The classical Inaba vibriocidal antibody seroconversion rates were 90.4% (95% CI, 86.4%-93.5%] in vaccine recipients at 10 days post-vaccination.

Vibriocidal Antibody Against Classical Ogawa, El Tor Inaba and El Tor Ogawa

• V. cholerae serogroup O1 consists of four major subtypes: classical Inaba, classical Ogawa, El Tor Inaba and El Tor Ogawa. Serum vibriocidal antibody against the three types of V. cholerae not contained in the vaccine, namely classical Ogawa, El Tor Inaba and El Tor Ogawa, was also measured in Study 2 and Study 4. The percentages of vaccine recipients who seroconverted against each of the 4 major biotype/serotypes of V. cholerae serogroup O1 at 10 days postvaccination (71.4% to 91.4%).

Pediatric Trial - Vibriocidal Antibody Against the Vaccine Strain (classical Inaba)

• Study 5

• The safety and immunogenicity of Vaxchora was evaluated in a randomized, double-blind, placebo-controlled study conducted in the US, which included a total of 550 patients 2 through 17 years of age who were not previously exposed to cholera. Patients were randomly assigned 6:1 to receive one dose of Vaxchora or placebo. Randomization was stratified by age into 3 age cohorts: 12 to less than 18 years of age (Cohort 1); 6 to less than 12 years of age (Cohort 2); and 2 to less than 6 years of age (Cohort 3).

• The classical Inaba vibriocidal antibody seroconversion rates were 98.5% (95% CI, 96.2%-99.4%] in vaccine recipients at 10 days post-vaccination.