Days after making some headlines with a press release about the data, the Novavax (NVAX) vaccine attempt has published on medRxiv. This is the first look at human data we have from an approach using coronavirus reconcinante proteins (plus an adjuvant, in this case a natural proprietary saponin product). The protein itself is produced in the good ol ‘Sf9 / baculovirus cell expression system, a true carcass over the years for recombinant proteins. I’m glad to see this because we need as many different techniques as we can get. So how well does it work?
This was done in 131 adults, with two injections three weeks apart. These were either 5 micrograms or 25 micrograms of protein, with and without the company owner̵7;s assistant. As seen in some of the other trials, there were six patients in a “sentinal” group who underwent the first observational dosing before the rest of the groups were vaccinated (five groups, 25 / group, with a placebo group). The antigen itself is the full-length Spike protein, with the mutated fur protein site and two protein substitutions introduced to stabilize the conformation. This is almost all the protein that the J&J vaccine (JNJ) is causing cells to produce through its adenovirus vector, so in this case, it is simply injected directly.
The reactions to the vaccine themselves look nice – the usual pain at the injection site and some reports of mild transient fever. These were most evident in the helper group, which basically tells you that the helper is probably just doing his immunogenic things. Overall, there seem to be no clear safety signs to worry about.
And indeed, the helper really helps a lot. On Day 21 (before the second injection), antibody levels against the Spike protein antigen were ten times higher in the support group compared to simple injections. The response was also stronger after the second injection, and by 14 days after that (Day 35 in general), antibody levels for the support groups were at least 100x higher than the non-supportive ones. So solve this! It is interesting that the levels were quite similar for 5 micrograms and 25 micrograms, so they should also help in the overall production of vaccines.
The effect on antibody neutralization was even more remarkable – it’s auxiliary or bust when measured that way (which is really the main figure, anyway). After the second vaccination, the printer reports that the neutralizing antibodies were 4x those seen in the convulsive serum of outpatient treated coronavirus cases, and that included the same range as the hospitalized convulsion cases. 16 patients were randomly selected from treatment groups to control the T cell response, and these showed CD4 + cells that were highly biased towards Th1. We do not know how long a response lasts – this paper covers up to two weeks on the second dose, but you can be sure that these numbers are being added up.
These look like strong results, and I am pleased that this candidate is in evidence of human efficiency. This is something to emphasize – we are all (enough of course) trying to do what calls can be based on Phase I immunogenicity data and challenging non-human experiments. But what matters is the real human data from the field through Phase II / III clinical trials. Right now, we have some vaccines that seem to have a good chance of working (that much between them). And we will list them in the only way they can be solved.
Editor’s note: The bullets for this article were selected by the editors of Seeking Alpha.