Covid-19 roundup: Top analyst pokes hole in AstraZeneca/Oxford data while scientists tamper hope for fast rollout
AstraZeneca and Oxford may have outshone Pfizer and BioNTech — at least in terms of media attention — with Phase I results on its Covid-19 vaccine initially. But a closer look suggests the adenovirus-based candidate doesn’t exactly match the bar set by mRNA vaccines on offer, including one from Moderna.
The bottom line, writes Bernstein’s Ronny Gal, is that while the AstraZeneca data are clearly positive, “in the competitive context they fail to impress.”
To be sure, all we’ve seen so far is preliminary biomarker data on antibodies and T cells that may indicate but by no means guarantee efficacy. Yet Gal takes issue, albeit with caveat, with the immunogenicity levels on display in AstraZeneca and Oxford’s dataset, published in The Lancet:
(i) The titers from immunized patients were lower than convalescent patients, where as BioNtech and Moderna vaccines both elicited IgGs substantially higher than convalescent controls (but each company used different convalescent group, so direct comparison is not possible).
(ii) Even the prime boost group was at most even with convalescent patients (lower on some of the assays).
(iii) Markers of cellular immunity are present, but not broken down between CD4 and CD8, peakearly and decline, and the magnitude is difficult to interpret.
It doesn’t help that the data are written up to highlight the small, 10-person group that received the prime/boost regimen, while reference values of convalescent sera and details on cellular immunity were missing.
“While these are common issues with scientific data presentation, in the context of the C19 global effort, the level of organization here is unimpressive,” he wrote.
Pfizer and BioNTech, by contrast, offered a much more positive impression in their not-yet peer-reviewed preprint. Antibody response was stronger in the vaccine group compared to patients who recovered from Covid-19, across a variety of viral mutants. CD4 and CD8 were presented separately with a breakdown for cytokines. There was even correlation between cellular and humoral immunity.
That said, any data supporting potential efficacy is good news, even if the strong results belong to the mRNA players, Gal wrote. They also seem to point to prime-boost as a favorable approach — an attitude that AstraZeneca execs echoed.
“Efficacy data will be out by September, these results suggest some efficacy is likely – let’s see how much (and for how long),” he concluded.
Rollout of Oxford vaccine by end of year possible but ‘there’s absolutely no certainty’ — lead scientist
As expectations mount following the publication of data, Oxford scientists and UK officials are both cautious about the precise timeline for a vaccine to become available.
The hope, expressed by their partners at AstraZeneca as recently as Monday, had been to have it for emergency use before 2020 ends. It’s a sentiment shared by the US, where the White House has set up Operation Warp Speed to hit the goal.
“The end of the year target for getting vaccine roll-out, it’s a possibility but there’s absolutely no certainty about that because we need three things to happen,” Sarah Gilbert, who leads the team that developed the adenovirus-based vaccine, told BBC Radio.
The ongoing late-stage trials would need to show that it works; the manufacturing partners would have to deliver on the million doses slated for September; and a signoff from regulators would be the final gating factor.
Even chief medical officer Chris Whitty and his deputy Jonathan Van-Tam don’t seem to agree on just how optimistic the country should be.
“The chance of us getting a vaccine before Christmas that actually is highly effective are, in my view, very low,” Whitty told lawmakers, per Reuters, while Van-Tam said he was “cautiously optimistic” it would happen.
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