Janssen Discloses Updated COVID-19 Vaccine Candidate Results to the FDA

The U.S. FDA's Vaccines and Related Biological Products Advisory Committee posted the JANSSEN BIOTECH, INC., Sponsor Briefing Document Addendum on February 24, 2021, for COVID-19 Vaccine Ad26.COV2.S VAC31518 (JNJ-78436735) meeting scheduled for February 26, 2021. 

At the time of submission of the EUA application (February 4, 2021), Janssen included the analysis on asymptomatic SARS-CoV-2 infections based on 965 Day 71 serology results.

In this addendum, Janssen highlights the impact of an updated analysis on asymptomatic SARS-CoV2 infections based on 2,892 Day 71 serology results.

Both the initial and updated analyses are based on the database cutoff for the primary analysis (January 22, 2021). Note that this is still an interim analysis of the Day 71 serology results.

Below is a copy of the impacted paragraphs of Section 7.1.6.6 of the Sponsor Briefing Document.

In a preliminary analysis of asymptomatic or undetected SARS-CoV-2 infection based on an assessment of (SARS-CoV-2 N IgG) seroconversion in 2,650 individuals with Day 71 results available, 50 asymptomatic or undetected cases occurred in the placebo group versus 18 cases in the Ad26.COV2.S group resulting in VE of 65.5% (95% CI: 39.91; 81.08).

When a sensitivity analysis was done removing all participants with symptoms at any time since screening prior to the SARS-CoV-2 N IgG positive result (i.e., removing the undetected cases with symptoms), 10 and 37 seroconversions occurred in the Ad26.COV2.S and placebo group, respectively (VE [95% CI]: 74.2% [47.13; 88.57]).

Based on 50 cases and 1,304 participants in the serology at-risk set in the placebo group, the seroconversion attack rate equals 3.8%.

Since these analyses are based on a larger number of N serology results, they supersede the results and conclusions on vaccine effectiveness against asymptomatic or undetected SARS-CoV-2 infections presented in the Sponsor Briefing Document.