The most sought-after goal in tackling the global COVID-19 will be the development of an effective vaccine that induces effective and long-lasting immunity against the virus, says IHS Markit in the latest report - Photo by Sinovac Office

JAKARTA (TheInsiderStories) – The most sought-after goal in tackling the global COVID-19 will be the development of an effective vaccine that induces effective and long-lasting immunity against the virus, says IHS Markit in the latest report. As of August 27, thirty vaccine candidates are currently in clinical trials, and these and other promising candidates are listed in the table below.

To date, five vaccine candidates from AstraZeneca (Britain), Sinovac (China), Moderna (United States), and two from Sinopharm (China) have entered Phase III development, one is in Phase II/III (from a collaboration between BioNTech from Germany and US’ Pfizer), four are in Phase II, and several more are in Phase I/II and Phase I.

One Phase I/II candidate from the Gamaleya Institute (Russia) has received a temporary authorization for public access on an initially limited basis in the country, prior to entering Phase III development, although little evidence has been released on the efficacy of this candidate. Several more candidates are expected to enter Phase III during September.

Gustav Ando, head of life sciences and industry services from IHS Markit, said, that several of the most advanced projects are based on non-replicating adenoviral vector technology, and the COVID-19 market may mark a breakthrough for this type of vaccine, which is as yet unproven, though widely researched, said IHS Markit in the latest survey.

He said, such vaccines may give rise to robust and effective immune responses, and are relatively safe, although there may be issues of pre-existing immunity to vectors based on human adenoviruses in individuals who have recently had adenoviral common colds.

“Several others are based on mRNA or plasmid DNA-based technologies, which are more experimental in nature, although generally acknowledged to be safe, easy to scale up, and with a strong research base indicating the potential for such vaccines to be effective,” He noted.

As with adenoviral vaccines, the pandemic may be proving ground for the DNA/RNA vaccine sector – which is backed by many years of research, but without approvals so far, said Ando.

“However, several vaccines using more conventional approaches, such as inactivated (killed) whole virions or isolated recombinant proteins (subunit vaccines), are also in clinical-stage development, and it will be interesting to see whether tried-and-tested approaches pay off in the end,” he rated.

Selected promising preclinical-stage projects, some of which are very close to initiating clinical development, have been listed. The success of any of these will depend on safety, level of neutralizing immunogenicity, strength and duration of protection, which are best measured in a large-scale randomized, double-blind, placebo-controlled Phase III trial, preferably in a country with a high background level of infections, in order to allow adequate differentiation of post-vaccination protection against real-world infections versus placebo.

“Several repurposed drugs have passed into emergency use in certain countries as potential direct anti-viral, but the clinical evidence base is still not strong. The injectable-only RNA replicase inhibitor remdesivir is the one showing the strongest evidence base for efficacy so far and has recently received conditional approvals in Europe, Canada, and certain other countries and many EUAs in Japan, the United States, and elsewhere,” Ando said.

An oral RNA replicase inhibitor, Avigan (favipiravir), has shown promising initial data in Japan, but is still awaiting full confirmation of efficacy in its original version, both in Japan and in many controlled trials around the world. Recently, he continued, the chloroquines have fallen out of favour in many territories, despite the initial granting of EUAs in countries such as France and America (now revoked).

Its now looking increasingly unlikely that they will retain their position as a recommended emergency therapeutic in any country, and they are likely to be supplanted by more promising direct anti-virals as they emerge. IHS Markit has evaluated current evidence and status for a selection of promising medicines under evaluation for COVID-19 infection and its complications.

Many of the drugs under the closest scrutiny currently are repurposed versions of existing medicines that have established safety profiles and could be approved relatively quickly, once the evidence base is confirmed to be adequate. Medicines that are currently receiving EUAs are highly likely to be superseded by more effective products – some with similar mechanisms – as results from controlled trials become available.

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