Photo: Rodger Bosch Agence France-Presse
The first phase of clinical trials expected to begin this summer on 100 to 200 young adults in good health.
The quebec-based company Medicago has developed a vaccine against the COVID-19 announced today that it has received very encouraging results in the animal. Strong of this first success, it plans to launch clinical trials in healthy people, as early as this summer.
The researchers of this biopharmaceutical company have administered a first dose of the vaccine to mice in order to verify its safety and its ability to induce a good immune response. They then proceeded to take blood samples of the animals, ten days after being vaccinated. The analysis of these blood samples revealed that ” the vaccine had stimulated the production of a good antibody level. Depending on the dose and the formulation administered, the antibody level was 100 to 10,000 times higher than before vaccination, ” said Nathalie Charland, senior director, scientific affairs and medical in Medicago.
Some animals have received the vaccine alone, whereas others were administered the vaccine combined with an adjuvant, that is to say, an immunostimulating designed to increase the immune response. “Many childhood vaccines, including the HPV vaccine, contain adjuvants. The addition of an adjuvant could reduce the effective dose, that is to say, the dose of the vaccine [antigen] needed to induce a good immune response. This would thus make it possible to produce more doses with the same quantity of vaccine [antigens] and therefore reach more people. The adjuvant can also be used to obtain an immune response faster, extend the duration of the protection afforded by the vaccine, or avoid the use of a booster dose, ” says Ms. Charland.
Precisely, the mice that have been vaccinated several weeks ago, have received, a few days ago, a booster dose. We will check in a few weeks if the latter has increased the immune response or not. “It is common to administer a booster dose of a vaccine that must protect against a new virus to which no one has ever been confronted with. Young children often need to receive more than one dose of vaccine, since they have never been exposed to viruses and bacteria that circulate. For example, adults receive only one dose of flu vaccine, while children younger than six months often have a need for a second dose to produce a good level of antibodies against the virus “, explains Ms. Charland.
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The positive data that have been collected up to now, as well as those that will be following the booster dose will help ” build a case that we will present to Health and the FDA, in the United States, in order to obtain authorization to conduct clinical trials in humans “, she says.
The first phase of clinical trials expected to begin this summer on 100 to 200 young adults in good health. It will aim to verify the safety of the vaccine and to determine the effective dose. To do this, we will administer a different dose for each group of people, and we measure then the immune response that leads to each of these doses, which will determine the dose that will protect best against disease.
If this first phase is successful, we will proceed with a second phase this fall, which will aim to validate the dose seemed to be the most adequate for a greater number of participants. This second phase will also confirm or refute the safety of the vaccine. In principle, one should also conduct a third phase which will be to “confirm the effectiveness of the vaccine on thousands of people, but the regulatory authorities may decide that there is an urgent need to vaccinate people as soon as possible,” says Ms. Charland.
If all of these clinical trials confirmed the efficacy and safety of the vaccine, doses could be produced in large scale in the facilities of Medicago, in Quebec city, as well as in those of North Carolina, where you will be able to prepare, respectively, 20 million doses, and 100 million doses per year. “We can vaccinate our own people “, noted Ms. Charland.
The vaccine that Medicago has developed is based on a technology that has proven its value since it is also used for vaccines against HPV and hepatitis A and B. The vaccine developed by Medicago consists of virus-like particles (VLPS), which were produced by plants which were inoculated with the gene responsible for the synthesis of spicules that emerge at the surface of SARS-CoV-2. The particles produced by plants are similar as well to the virus and act as a decoy for the immune system which then induces an immune response against this foreign body.
Of course, the vaccine developed by Medicago has not moved through the first step of a long process. “Laboratory mice often respond favorably to a foreign antigen because they have not been in contact with many pathogens. There is hope that the vaccine will work in humans, although this is not guaranteed. Nevertheless, this first step gives us the tools to continue the development of the vaccine “, says dr. Charland.