COVID-19: UK Scientists using antibodies to create treatments that protect against COVID-19.

 

In 2020, scientists in the United Kingdom, began an innovative trial to test a drug made from antibody created by vaccine maker AstraZeneca. They hoped this drug known as AZD7442 will provide instant and long lasting protection against COVID-19.

The trial was separated into two studies which are being run by the University College London Hospitals NHS Trust (UCLH). The UCLH has declared that these antibodies are Long Acting AntiBody (LAAB).

UCLH had also said its new vaccine research centre, which opened in December to help accelerate the development of new vaccines and treatments during the pandemic, was running the clinical trials testing the LAAB combination treatment to protect against COVID-19.

The first study, called Storm Chaser is led by UCLH virologist Dr. Catherine Houlihan, who recruited the first participant in the world for the study earlier this month and has recruited 10 participants since then.

"We know that this antibody combination can neutralise the virus, so we hope to find that giving this treatment via injection can lead to immediate protection against the development of COVID-19 in people who have been exposed - when it would be too late to offer a vaccine," said Houlihan.

The second study, called Provent, used AZD7442 in people who may not respond to vaccination, for instance where someone has a compromised immune system or are at increased risk of COVID-19 infection due to factors such as age and existing conditions.

"We will be recruiting people who are older or in long-term care, and who have conditions such as cancer and HIV which may affect the ability of their immune system to respond to a vaccine.

"We want to reassure anyone for whom a vaccine may not work that we can offer an alternative which is just as protective," said Dr Nicky Longley, UCLH infectious diseases consultant leading the Provent study.

Antibodies are protein molecules that the body produces to help fight infections. Monoclonal antibodies are artificially produced in a laboratory and designed as possible medical treatments. They are designed to be injected directly into the body, unlike vaccines which "train" the immune system itself to produce antibodies.

"These two clinical trials are an important addition to testing new therapeutic approaches, as antibody treatments may offer an alternative to patient groups who cannot benefit from a vaccine, such as immuno-compromised patients," said Professor Stephen Powis, the medical director of National Health Service (NHS) England.

The LAABs have been engineered with AstraZeneca's "proprietary" half-life extension technology to increase the durability of the therapy for six to 12 months after a single dose of the drug. The combination of two LAABs is also designed to reduce the risk of treatment resistance by the COVID-19 virus.

"AZD7442 has the potential to be an important preventative and therapeutic medicine against COVID-19, focusing on the most vulnerable patients. This work complements our vaccine development programme," said Mene Pangalos, AztraZeneca Executive Vice-President for BioPharmaceuticals Research and Development.

"Storm Chaser is exploring the use of a combination of monoclonal antibodies given intramuscularly in those who have been exposed to SARS-CoV-2 - a setting where vaccination would not have time to work and we have no other proven therapies to date. This makes Storm Chaser an important study that may have a large impact on our ability to control this infection," noted Professor Andrew Ustianowski, who is the chief investigator of the new studies.

UCLH said that in both Provent and Storm Chaser, researchers will assess whether the treatment reduces the risk of developing COVID-19 and/or reduces the severity of infection compared to a placebo.

Key participant groups in the Storm Chaser trial will include healthcare workers, students who live in group accommodation, and patients who are exposed to anyone with the SARS-CoV-2 virus as well as residents of long-term care facilities and industrial/military sector.

"Both Storm Chaser and Provent are crucial to finding a solution to this pandemic," said Professor Vincenzo Libri, who leads the UCLH Clinical Research Facility backed by the UK's National Institute for Health Research (NIHR).

"The opening of our new Vaccine Research Centre will help to propel our fight against the virus, meet our aspiration to save as many lives as possible, and ensure a return to normality," he said.

"The recent progress on vaccines is hugely welcome, and developing these additional treatments will be vital to ensure everyone in society can be offered protection against COVID-19," UCLH Chief Executive, Professor Marcel Levi said.

What is the latest on Storm Chaser?

On June 15, 2021, AstraZeneca announced results from the trial assessing the safety and efficacy of AZD7442, a long-acting antibody (LAAB) combination, for the prevention of symptomatic COVID-19 in participants recently exposed to the SARS-CoV-2 virus. Unfortunately, the trial did not meet the primary endpoint of post-exposure prevention of symptomatic COVID-19 with AZD7442 compared to placebo.

The trial participants were unvaccinated adults 18 years and over with confirmed exposure to a person with a case of the SARS-CoV-2 virus within the past eight days. In the overall trial population, AZD7442 reduced the risk of developing symptomatic COVID-19 by 33% (95% confidence interval (CI): -26, 65) compared to placebo, which was not statistically significant.

The trial included 1,121 participants in a 2:1 randomisation AZD7442 to placebo. Twenty-three (23) cases of symptomatic COVID-19 emerged in the AZD7442 group (23 out of  749 participants) and 17 cases emerged in the placebo group (17 out of 372 participants). All participants had a negative SARS-CoV-2 antibody test on the day doses were administered to exclude prior infection, and a nasopharyngeal swab was also collected and subsequently analysed for SARS-CoV-2 by RT-PCR to detect virus.

In a pre-planned analysis of SARS-CoV-2 PCR positive (detectable virus) and PCR negative (no detectable virus) participants, AZD7442 was able to reduce the risk of developing symptomatic COVID-19 by 73% (95% CI: 27, 90) compared with placebo group, in participants who tested negative on their PCR test at the time of dosing. In a post-hoc analysis, in participants who were PCR negative at baseline, AZD7442 reduced the risk of developing symptomatic COVID-19 by 92% (95% CI: 32, 99) versus placebo more than seven days following dosing, and by 51% (95% CI: -71, 86) up to seven days following dosing.

Myron J. Levin, MD, Professor of Pediatrics and Medicine, University of Colorado School of Medicine, US, and principal investigator on the trial, revealed: "The results of STORM CHASER suggest that AZD7442 may be useful in preventing symptomatic COVID-19 in individuals not already infected. The PROVENT trial will give us more clarity in this patient population. While COVID-19 vaccination efforts have been successful, there is still a significant need for prevention and treatment options for certain populations, including those unable to be vaccinated or those who may have an inadequate response to vaccination."

This is still good news. Why? Even though it cannot be used for persons who are already infected it can be an alternative treatment for persons who want to protect themselves from the novel coronavirus but for one reason or another cannot take the current vaccines. Persons with autoimmune diseases for example, can take these antibodies when they become available or another more improved version of the treatment.

Conclusion

It's quite possible that any day now scientists will come up with effective treatments to deal with the COVID-19 virus besides the vaccines. Let's hope for the best. We need all of them!

References:

Astrazeneca. Update on AZD7442 STORM CHASER trial in post-exposure prevention of symptomatic COVID-19, Published 15 June 2021, https://www.astrazeneca.com/media-centre/press-releases/2021/update-on-azd7442-storm-chaser-trial.html