Johnson & Johnson’s lead vaccine candidate protected against infection with SARS-CoV-2, the virus that causes COVID-19, in preclinical studies. Data shows the investigational adenovirus serotype 26 (Ad26) vector-based vaccine elicited a robust immune response as demonstrated by "neutralizing antibodies," successfully preventing subsequent infection and providing complete or near-complete protection in the lungs from the virus in non-human primates (NHPs) in the preclinical study. A Phase 1/2a first-in-human trial of the vaccine Ad26.COV2.S in healthy volunteers began in the U.S. and Belgium.

The Janssen COVID-19 clinical trial program, including the Phase 1/2a trial and the Phase III clinical trial program, will evaluate both one- and two-dose regimens of Ad26.COV2.S in parallel studies. The Phase 1/2a trial will evaluate the safety, reactogenicity (expected reactions to vaccination, such as swelling or soreness), and immunogenicity of Ad26.COV2.S in over 1,000 healthy adults aged 18 to 55 years, as well as adults aged 65 years and older. Planning also is underway for a Phase IIa study in the Netherlands, Spain and Germany and a Phase I study in Japan.

Discussions are underway with partners with the objective to start a pivotal Phase III trial of the single vaccine dose versus placebo in September, pending the interim data of the Phase I and II trials and approval of regulators. The company also is planning to start a parallel Phase III trial of a two-dose regimen versus placebo.