Regulatory Decision Summary for Vaxchora

The purpose of this New Drug Submission (NDS) was to seek authorization for Vaxchora for the active immunization against diarrheal disease caused by Vibrio cholera serogroup O1 in persons 2 through 64 years of age traveling to cholera-affected areas.

The submission was reviewed using the international review work sharing model with the Access Consortium. Health Canada reviewed the Quality module, and the Australian Therapeutic Goods Administration (TGA) reviewed the Clinical module.

The decision to authorize Vaxchora for ‘the active immunization against diarrheal disease caused by Vibrio cholera serogroup O1 in persons 2 through 64 years of age traveling to cholera-affected areas’ was based on the efficacy and safety presented in the submitted clinical study program.

• The vaccine is taken by mouth and is used to help protect people who are travelling to an area where there is a risk of diarrhea caused by cholera. It stimulates the body’s natural defense in the gut and mimics the natural infection.

• The vaccine is used for protection from cholera in persons 2 to 64 years of age. The vaccine is effective against the most common serogroup of cholera (O1) but does not work against uncommon serogroups such as O139.

• Vaxchora vaccine prepares the immune system (the body's defenses) to fight against cholera bacteria if you come in contact with it. When you take the vaccine, the immune system makes proteins called antibodies against the cholera bacterium and its toxin (harmful substance) that causes diarrhea.

• The efficacy of Vaxchora in preventing moderate to severe diarrhea was demonstrated in adults aged 18-45 years showing that the vaccine protected against a live virulent V. cholerae O1 El Tor Inaba challenge at 10 days and 3 months post-vaccination. The primary endpoint was the occurrence of moderate or severe diarrhea (≥3.0 L cumulative purge) post-challenge. The co-primary objectives of the study were to demonstrate that the lower 95% confidence bound on the protective efficacy was at least 30% at both of these time points. Success of both the 10-Day and 3-Month Challenges was required to achieve success for the trial as a whole. The co-primary objectives of the study were met with 10-Day protective efficacy of 90.3% (lower 95% Confidence Interval [CI] bound of 62.7%) and 3-Month protective efficacy of 79.5% (lower 95% CI bound of 49.9%). These results reflect a clinically meaningful level of protection for Vaxchora.

• The safety profile of Vaxchora was favorable, there were no severe adverse events association with the vaccine. The vaccine-associated diarrhea was typically mild and resolved spontaneously within 2 days in the majority of cases.

• The vaccine should not replace standard preventive hygiene measures. Travellers should take all necessary precautions to avoid contact with or ingestion of potentially contaminated food or water. Rehydration measures must be taken in the event of diarrhea.

For further details about Vaxchora, please refer to the Product Monograph, approved by Health Canada and available through the Drug Product Database.