The ENSEMBLE 2 trial is being conducted in collaboration with the UK National Institute for Health Research (NIHR). It will enrol up to 30,000 participants in the UK, the US, France, Germany, South Africa, Spain, Belgium, Colombia, and the Philippines. Clinical trial sites have been selected on the basis of countries or areas with high incidence of COVID-19 and the ability to start the study quickly.
The study will assess the efficacy of the vaccine after both the first and second dose to see if a 2-dose regimen can increase the duration of protection given by the vaccine.
Johnson & Johnson’s vaccine candidate differs from most other frontrunners in that it is based on a 1-dose regimen: as is being tested in its first ENSEMBLE trial which started in September (this trial is recruiting up to 60,000 people across the US, Argentina, Brazil, Chile, Colombia, Mexico, Peru and South Africa).
However, the potential of a 2-dose regimen is already being explored in earlier stage trials: with J&J now announcing its progression into Phase 3 trials yesterday [November 15].
At a glance: ENSEMBLE and ENSEMBLE 2
Phase 3 ENSEMBLE trial: 1 dose regimen
- A randomized, double-blind, placebo-controlled Phase 3 study to assess the efficacy and safety of the vaccine candidate for the prevention of SARS-CoV-2-mediated COVID-19 in adults aged 18 and over.
- Launched September 2020
- 60,000 people across the US, Argentina, Brazil, Chile, Colombia, Mexico, Peru and South Africa
- Single-dose vaccine (dose level of 5×1010 virus particles) administered on Day 1.
- Study protocol published here and study information here
Phase 3 ENSEMBLE 2 trial: 2 dose regimen
- A randomized, double-blind, placebo-controlled Phase 3 study to assess the efficacy and safety of the vaccine candidate for the prevention of SARS-CoV-2-mediated COVID-19 in adults aged 18 and over.
- Launched November 2020
- 30,000 people across the UK, the US, France, Germany, South Africa, Spain, Belgium, Colombia, and the Philippines.
- Participants will receive the vaccine on day 1 and day 57.
- Study information here.
The Janssen COVID-19 vaccine candidate, JNJ-78436735 (also known as Ad.26.COV2.S), is a recombinant vector vaccine that uses a human adenovirus to express the SARS-CoV-2 spike protein in cells.
It uses the company’s existing AdVac technology platform (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 and ENSEMBLE 2 trials follow positive interim results from the J&J's ongoing Phase 1/2a clinical study, which is studying the safety profile and immunogenicity of both a single-dose and two-dose vaccination. The interim analysis showed that a single dose of the COVID-19 vaccine candidate induced a robust immune response and was generally well-tolerated.
The vaccine is estimated to remain stable for two years at -20 °C and at least three months at 2-8° C. This would make the vaccine candidate compatible with standard vaccine distribution channels, says J&J.
