Well, it’s definitely been a Vaccine Week around here, but it’s understandable. And we’ll finish off the week with a look at some types that we haven’t seen report yet. The news is. . .mixed.
First off is a preliminary report on the inactivated virus vaccine from Sinopharm – more specifically, their China National Biotec Group division, and even more specifically CNBG’s Beijing Institute of Biological Products. As a side note, if you find the organizational structure of these Chinese efforts somewhat confusing, come sit right over here next to me. A press release from the United Arab Emirates’ Ministry of Health and Prevention says that a trial there showed 86% efficacy and that there were no serious safety concerns. I would bet that this is a higher figure than most people expected from an inactivated-virus candidate – it’s an older technology that doesn’t always come through (but has certainly also generated some very useful vaccines in the past).
Unfortunately, that’s about all the release has to say – there are few further details. The 86% is said to be for preventing coronavirus infection, but we don’t know if this was measured by number of patients with symptoms or counting in asymptomatics via PCR testing. The release also says that the vaccine was 100% effective in preventing moderate or severe cases, which is also very good, of course. It’s a two-shot dosing regimen, and the vaccine itself is said to have no special storage requirements. So there’s a lot of promising stuff here, but there’s a lot to wonder about as well. I know that we’ve had a lot of press releases in this vaccine clinical trial business so far, but most of them have them have been a bit more informative than this. And although some of the Chinese development efforts have released and published good data sets, others have been very much lacking, and this is one of them.
For example, neither Sinopharm nor the Chinese authorities have had any comment on this announcement. And that’s odd. Indeed, the New York Times reports that one of their reporters got through to Sinopharm only to have them hang up the phone when asked for comment. So I’m not just being hard on this one because it’s from a Chinese company – this is weird by any nation’s standards. If I’m going to give Oxford and AstraZeneca grief for the way they rolled out their recent trial announcement – and I do, because they deserve some – then I’m going to give Sinopharm some for this. If they weren’t ready for a press release from the UAE government, they should say so. Hanging up the phone on people is not the way to build confidence in your organization and its skills. At any rate, the efficacy numbers from this single press release are good news. The UAE has now approved it, and shipments of it are already going to Egypt and Indonesia, among other countries. I would just feel better if I could hear the actual developers of the vaccine say something about it, and with some more numbers attached.
We also had news this morning from the GSK/Sanofi effort, but the news is not good. They have been working on a recombinant protein vaccine with the addition of GSK’s adjuvant, but the companies announced that a look at immunogenicity in Phase I volunteers showed an inadequate response in older patients. The 18-49 year old cohort apparently looked good, but when compared to convalescent plasma antibody levels, the levels in the older vaccinated patients were not. The companies plan to start up again in the clinic in February with an improved antigen formulation, but this will definitely delay their vaccine to (probably) the end of next year, and that’s assuming that the new version works as hoped.
That’s unfortunate. We need as many solid vaccines as we can get, and I don’t think anyone was really expecting something like this from the Sanofi/GSK team (they certainly weren’t). The two companies have a long track record in this area, but immunology is what it is – these results show that we can take nothing for granted. In fact, together with the lower efficacy seen in the Oxford/AZ candidate, I have to say that this is making the mRNA platforms look stronger all the time. More on this in a separate post next week. Anyway, in the same way that the Oxford/AZ data make me very curious about what we’ll see from J&J’s trial, these results make me similarly ready to see what Novavax will report with their own recombinant protein/adjuvant candidate. But they did have reasonable antigenicity numbers, at least. And in that first link in this post, the team at Science says that they believe that another inactivated-virus candidate (from Sinovac) may soon report on its trial in Brazil, so we’re going to have plenty of comparisons to think about.
Finally, word has come that an unusual vaccine candidate has had to stop development. In my earlier huge vaccine roundup posts, I mentioned the University of Queensland and their “molecular clamp” technique. Here’s more on how that is supposed to work. The idea is to use a trimeric protein that’s from HIV, a part of its gp41 glycoprotein, as a molecular platform to display the antigen proteins from whatever other virus you choose. The Queensland candidate (which was being developed with biotech company CSL) displayed the coronavirus spike protein this way, in what was believed to be exclusively its pre-fusion conformation. The idea looked like it would be readily adaptable to many viral proteins, and easier to realize than some of the other scaffolding ideas like this that have also been looked at.
Unfortunately, the use of this protein fragment also caused antibodies to be raised to it as well as to the Spike protein part, and that led to false-positive HIV tests in the trial participants. It’s important to note that these are indeed false positives – the vaccines used only a piece of one HIV protein and this has nothing to do with an actual HIV infection, of course. But wide use of such a vaccine would basically blow up the ability to do routine HIV blood screening, and that’s not good. Especially when there are other vaccine candidates out there with no such liability. Work on this one has ceased, and this would appear to throw into doubt any further plans to use the gp41 platform for future vaccines.
Update: there’s some more news. AstraZeneca today says they’re looking at combinations of the Oxford/AZ adenovirus vector vaccine with others. That includes the mRNA candidates and (interestingly) the Russian “Sputnik” vaccine from Gamaleya. Details on that latter one have been very much lacking. I’ve written here about the possibility of people getting more than one type of vaccine, so I’ll be glad to see some controlled data on the mix-and-match approach in general, while keeping in mind that (immunology!) every one of these situations could be different, all the way down to what order the vaccines are given in. To me, this also suggests that AstraZeneca is hedging against the possibility that their candidate may simply not be able to compete as a standalone agent in the eventual coronavirus vaccine landscape. . .