Johnson & Johnson Starts Phase 3 Study of COVID-19 Vaccine Candidate

Johnson & Johnson launched a late-stage study of its COVID-19 vaccine candidate JNJ-78436735 following positive interim results from a phase 1/2a trial. The ENSEMBLE study will enroll up to 60,000 volunteers and will evaluate the safety and efficacy of a single vaccine dose versus placebo in preventing COVID-19.

Chief scientific officer Paul Stoffels suggested that results of the ENSEMBLE trial are expected by year end or early in 2021. The trial is designed to test for a vaccine that is 60% effective, with Stoffels noting that Johnson & Johnson will start counting cases of COVID-19 infections within the study population 15 days after individuals are vaccinated.

JNJ-78436735, which utilizes Johnson & Johnson’s AdVac technology platform, will also be studied in a separate phase 3 trial to explore a two-dose regimen of the vaccine candidate. The company announced last month, alongside a supply deal, that the UK agreed in principle to co-fund a late-stage study exploring a two-dose regimen of JNJ-78436735.

Single dose produces immunogenicity

Johnson & Johnson initiated the phase 1/2a study of JNJ-78436735, also known as Ad26.COV2.S, at the end of July. The drugmaker said Wednesday that interim results from the trial demonstrated the safety and immunogenicity after a single vaccination, supporting further development. Stoffels noted that the safety and level of protection in the study were on par with that seen in animal studies, with a single dose offering sufficient protection “for a long time.” The data are due to be published online imminently.

According to Johnson & Johnson, it has continued the scaling up of its manufacturing capacity for JNJ-78436735 and remains on track to produce one billion doses of the vaccine each year. The company added that the first batches of its COVID-19 vaccine are expected to be available for emergency use authorization in early 2021.