Johnson & Johnson Begins Phase 3 Trial of One-Dose COVID-19 Vaccine Candidate

Johnson & Johnson (New Brunswick, NJ, USA) has launched its large-scale, pivotal, multi-country Phase 3 trial (ENSEMBLE) for its COVID-19 vaccine candidate, JNJ-78436735, being developed by its Janssen Pharmaceutical Companies (Beerse, Belgium).

The Janssen COVID-19 vaccine candidate leverages the company’s AdVac technology platform, which was also used to develop and manufacture Janssen’s European Commission-approved Ebola vaccine and construct its Zika, RSV, and HIV vaccine candidates. The Phase 3 ENSEMBLE study is a randomized, double-blind, placebo-controlled clinical trial designed to evaluate the safety and efficacy of a single vaccine dose versus placebo in up to 60,000 adults 18 years old and older, including significant representation from those that are over age 60. The trial will include those both with and without co-morbidities associated with an increased risk for progression to severe COVID-19, and will aim to enroll participants in Argentina, Brazil, Chile, Colombia, Mexico, Peru, South Africa and the US. In order to evaluate the effectiveness of Janssen’s COVID-19 vaccine, countries and clinical trial sites which have a high incidence of COVID-19 and the ability to achieve a rapid initiation will be activated.


The initiation of the ENSEMBLE trial follows positive interim results from the company’s Phase 1/2a clinical study, which demonstrated that the safety profile and immunogenicity after a single vaccination were supportive of further development. Based on these results and following discussions with the US Food and Drug Administration (FDA), ENSEMBLE will enroll up to 60,000 volunteers across three continents and will study the safety and efficacy of a single vaccine dose versus placebo in preventing COVID-19. With Janssen’s AdVac technology, the vaccine, if successful, is estimated at launch to remain stable for two years at -20 °C and at least three months at 2-8° C. This makes the vaccine candidate compatible with standard vaccine distribution channels and would not require new infrastructure to get it to the people who need it. Johnson & Johnson has continued the scaling up of its manufacturing capacity and remains on track to meet its goal of providing one billion doses of a vaccine each year. The company anticipates the first batches of a COVID-19 vaccine to be available for emergency use authorization in early 2021, if proven to be safe and effective.

“As COVID-19 continues to impact the daily lives of people around the world, our goal remains the same - leveraging the global reach and scientific innovation of our company to help bring an end to this pandemic,” said Alex Gorsky, Chairman and Chief Executive Officer, Johnson & Johnson. “As the world’s largest healthcare company, we are bringing to bear our best scientific minds, and rigorous standards of safety, in collaboration with regulators, to accelerate the fight against this pandemic. This pivotal milestone demonstrates our focused efforts toward a COVID-19 vaccine that are built on collaboration and deep commitment to a robust scientific process. We are committed to clinical trial transparency and to sharing information related to our study, including details of our study protocol.”

“We remain fully focused on developing an urgently needed, safe and effective COVID-19 vaccine for people around the world,” said Paul Stoffels, M.D., Vice Chairman of the Executive Committee and Chief Scientific Officer, Johnson & Johnson. “We greatly value the collaboration and support from our scientific partners and global health authorities as our global team of experts work tirelessly on the development of the vaccine and scaling up our production capacity with a goal to deliver a vaccine for emergency use authorization in early 2021.”

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