- A Novavax coronavirus vaccine candidate has completed its Phase 1 trial with promising results.
- The drug NVX-CoV2373 induced neutralizing antibodies in all the volunteers who received the injections. The AT cell response was also seen in part of the group of volunteers, the company said.
- Pending the successful completion of a Phase 3 trial, the company could deliver up to 100 million doses of the drug by the end of 2020.
Several candidate vaccines are in advanced stages of human trials, and research may be ready this fall. At this point, new coronavirus drugs could be used under emergency use authorizations in the United States and other countries. The investigational drugs Moderna, AstraZeneca / Oxford and Pfizer / BioNTech have made significant progress in the early stages of human trials and will each include around 30,000 volunteers in their phase 3 trials. But there is no guarantee that any of the first vaccines to have reached the final stage of testing will confirm the initial conclusions of this next phase. Needless to say, not achieving the necessary efficiency would prevent regulators from approving drugs for public news. The good news is that more than 150 COVID-19 vaccination efforts are underway around the world, and many more investigational drugs are being studied in early-stage clinical trials. The more shots on goal the world takes when it comes to developing a vaccine, the better the chances of at least one of them reaching the net. And of course, the world could use more than one effective COVID-19 vaccine to speed up vaccination programs in the years to come.
Novavax has just announced two sets of results for its experimental vaccine and both are very encouraging. The drug elicited the desired immune response in all phase 1 volunteers, including neutralizing antibodies that can prevent the virus from replicating and T cells that can fuel an immune response after these antibodies disappear.
The company included 131 healthy Australian adults between the ages of 18 and 59 in the Phase 1 portion of its Phase 1/2 trial, dividing them into multiple groups that received either version of the compound or a placebo. The drug NVX-CoV2373 was tested at doses of 5 and 25 μg which were administered twice to each volunteer.
The vaccine was genetically engineered “using Novavax’s recombinant nanoparticle technology to generate an antigen derived from the coronavirus (S) peak protein”. Novavax used an adjuvant called Matrix-M in combination with the investigational medicine to stimulate the immune response. The drug stimulates “the entry of antigen presenting cells into the injection site” and improves “the presentation of the antigen in the local lymph nodes, stimulating the immune response,” the company said in a press release. .
The most common side effects after the first injection included tenderness and pain, although some patients experienced headaches, fatigue, and myalgia. The side effects were more severe after the second injection, but the symptoms disappeared after about two days.
The company claims that all subjects developed neutralizing “anti-spike” antibodies capable of blocking the virus, regardless of the dosage used. The resulting antibodies were at the same level or higher than the antibodies measured in the patients who survived the infection. Cellular immune responses were measures in a subset of patients, while researchers looked for “antigen-specific polyfunctional CD4 + T cell responses induced by NVX-CoV2373 with a strong bias in favor of the Th1 phenotype.”
Recent studies have shown that circulating antibodies can disappear from the blood of COVID-19 survivors within three months of infection. But immunity doesn’t just go away. T cells in the blood remember the pathogen and trigger a rapid immune response on a second encounter which may include the destruction of infected cells and the production of new antibodies. Other vaccines have also shown the same double response of the immune system.
It should be noted that Novavax is one of the drugmakers that received money under the Operation Warp Speed program. The $ 1.6 billion funding is being used to complete late-stage development, including a Phase 3 trial. Novavax plans to deliver 100 million doses of NVX-CoV2373 by the end of 2020, once the approval received. It is not known when phase 3 will begin.
Novavax has submitted its research for peer review to a scientific journal and will publish a pre-printed version in medRxiv at some point in the future. A second study that will be shared soon shows preclinical results for the same drug. The researchers tested NVX-CoV2373 on cynomolgus macaques, which were exposed to the virus after receiving the injections. The vaccine prevented viral replication in the upper and lower respiratory tract in subjects. CNN reports that one of 12 monkeys tested showed signs of infection in the lungs, but they disappeared just two days later.