Covid-19 roundup: Regeneron scores $2.6B US supply deal for antibody cocktail; Brazilian researchers walk back efficacy rate for Sinovac's candidate
The US is continuing to buy up every dose of antibody cocktail that Regeneron can produce, signing off on a $2.625 billion deal to follow $450 million of investments made in July.
Whether Regeneron can deliver the best-case scenario — 1.25 million doses by the end of June — depends in large part on the FDA’s stance on the 1,200mg dose. The pair of antibodies, casirivimab and imdevimab, is currently authorized only at the 2,400mg dose level (1,200mg each). Right now, the big biotech is in the process of delivering doses to treat 300,000 people following the emergency use authorization in November.
So if regulators don’t expand the EUA to cover the lower-dose regimen — still under clinical testing for the same population, non-hospitalized, mild to moderate Covid-19 patients at high risk of progression — soon, Regeneron will only be able to supply around 750,000 finished doses.
In a pivotal outpatient trial, only the higher dose helped patients achieve statistically significant reductions in virus levels and require fewer medical visits. But company execs emphasized the data on seronegative patients, noting that those who are most at risk benefited the most from their drug, even at low doses.
“Additionally, as expected, the virus continues to mutate, with the possibility of developing resistance to any one antibody,” president and CSO George Yancopoulos said in a statement. “The Regeneron cocktail of two antibodies, each targeting a different site on the virus, reduces the possibility of the virus becoming resistant.”
The Department of Health and Human Services and the Department of Defense are purchasing the antibodies from Regeneron and plan to offer them to Americans at no cost, though hospitals may charge for administration. To date, the HHS Office of the Assistant Secretary for Preparedness and Response says it has allocated more than 127,700 treatment courses.
“With COVID-19 cases continuing to rise, treating people with mild or moderate infections can help prevent hospitalizations, which will reduce the burden on healthcare systems,” said Robert Kadlec, HHS Assistant Secretary for Preparedness and Response.
Outside the US, Regeneron has teamed up with Roche to develop, manufacture and distribute casirivimab and imdevimab globally. The goal is to have more than 2 million treatment doses available annually.
Brazilian researchers walk back efficacy rate for Sinovac’s candidate
Less than a week after touting a 78% efficacy rate for Sinovac’s Covid-19 candidate, Brazil’s Butantan Institute is walking back that claim. Scientists are now saying the vaccine is only 50.4% effective at preventing symptomatic infections — just high enough to meet regulatory standards, Reuters reported.
Why the stark difference? Researchers said partial results showed a 78% efficacy rate against “mild-to-severe” cases, leaving out another group of “very mild” cases entirely, according to Reuters.
Trial sites around the world have reported varying efficacy rates for the Chinese vaccine, dubbed CoronaVac. Researchers in Turkey said the candidate was 91.25% effective based on an interim analysis. And scientists in Indonesia said interim data showed a 65% efficacy rate.
The 50.4% figure is much lower than the efficacy rates of Pfizer/BioNTech and Moderna’s candidates, which are 95% and 94.5% effective at preventing symptomatic cases, respectively.
The news comes weeks after unnamed sources involved in the Brazilian trials told the Wall Street Journal that Sinovac’s candidate was at least 50% effective.
Brazilian president Jair Bolsonaro is a known skeptic of the Chinese vaccine. However, a state governor said last month that Brazil would buy 46 million doses, Reuters reported.
CoronaVac uses inactivated virus to trigger an immune response. It was authorized for emergency use by the Chinese government back in July. And in June, Sinovac signed a deal with Instituto Butantan to advance clinical trials to Phase III.
Brazil briefly put the trial on hold in November, following the death of a participant. It resumed shortly after, and the state government revealed that the volunteer had died by suicide.
In early December, Sinovac struck a deal with China’s Sino Biopharmaceutical for $515 million to double production capacity. In return, Sino Biopharmaceutical will get a 15.03% interest in Sinovac Life Sciences. At the time, Sinovac said it would be able to pump out up to 600 million doses annually with an added production facility. — Nicole DeFeudis
Synairgen doses first patient with repurposed interferon beta-1a treatment
Synairgen has dosed the first patient in a Phase III trial to see if its COPD and asthma candidate works against Covid-19.
In a small Phase II trial, Synairgen says hospitalized Covid-19 patients who took its inhalable interferon beta-1a formulation, SNG001, were twice as likely to recover within 14 days than patients on a placebo. Parexel Biotech is now helping conduct the Phase III trial which has already initiated several UK sites, with more in the US and the EU expected to follow. The study will take place across 20 countries, enrolling a total of 610 Covid-19 patients who require supplemental oxygen.
“We need treatments as well as vaccines to fight highly pathogenic viruses such as SARS-CoV-2,” CEO Richard Marsden said in a statement. “Development of treatments like ours will remain necessary in cases where vaccines are not effective, for those who do not get vaccinated, and in case the virus mutates to the point where vaccines become less effective.”
Marsden told Endpoints News in November that what interested the biotech most during Phase II was time to full recovery. For the purposes of the study, Synairgen defined “full recovery” as the point where a patient no longer experiences limitations in everyday activities. By that measure, 21 patients (44%) in the treatment arm reached full recovery over the 14-day treatment course, versus 11 (22%) in the placebo group.
“The thing that we’re most excited about is getting people back to this level of no limitation of activities, and you’re more than twice as likely — approaching three times as likely in some of the analyses — of getting back to that level if you’re on drug compared to placebo,” Marsden said in November.
After primary and secondary endpoint results are reported, participants in Phase III will continue to be assessed for long-term Covid-19 symptoms. — Nicole DeFeudis
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