What is a monoclonal antibody cocktail? How is Evusheld different from Covishield vaccine or any other vaccine in the market?
Evusheld is a combination of two long-acting monoclonal antibodies (mAbs) – tixagevimab and cilgavimab – derived from convalescent patients after SARS-CoV-2 virus. Combining two monoclonal antibodies allows them to work synergistically to enhance the potential for improving the effectiveness of treatment, and to evade the potential resistance that might emerge with the appearance of new variants and strains of SARS-CoV2.15.
It is the only antibody therapy authorised for emergency use in the US for the pre-exposure prophylaxis (prevention) of COVID-19. The cocktail is intended to help protect the most vulnerable populations, such as the immunocompromised, who may not mount a sufficient immune response to COVID-19 vaccination.
Preventing immunocompromised individuals from getting COVID-19 rather than waiting to treat this vulnerable population once they become infected is an important goal in the fight against the pandemic.
Evusheld is also authorised for emergency use for prevention of COVID-19 in several other countries, including France, Spain, Germany, Italy, Bahrain and Egypt, with rolling reviews underway in the UK and the EU.
Tell us about the recent developments of this monoclonal antibody cocktail. Is this effective against all the variants of corona virus?
By combining two potent antibodies with different and complementary activities against the virus, Evusheld was designed to evade potential resistance with the emergence of new COVID-19 variants.
A new independent study by the US Food and Drug Administration (FDA) shows that Evusheld retains neutralising activity against the Omicron SARS-CoV-2 variant (B.1.1.529). The pre-clinical data was generated by pseudovirus testing of the full Omicron variant spike and showed that the combination of the antibodies comprising Evusheld, retains neutralisation activity against the Omicron variant.
These data add to the growing body of pre-clinical evidence demonstrating that Evusheld retains activity against all tested variants of concern to date.
The Omicron variant was not in circulation during the Evusheld clinical trials. Further data are needed to understand the implications of this observation in clinical practice. We are conducting additional studies to further evaluate Evusheld against the Omicron variant. Data from this research is anticipated soon.
We remain optimistic that Evusheld will retain its efficacy against the Omicron variant and continue to provide a robust level of protection.
What went behind making this long-acting antibody (LAAB)? Tell us in detail about what was found in the Provent and Tackle trials.
No one vaccine or therapy can eliminate COVID-19, but multiple approaches could help to reduce the spread of the virus, defend those most vulnerable to infection, deliver better outcomes for patients and ultimately allow the world to return to normal. Despite the roll out of vaccines across the world, there remains an unmet need for vulnerable populations, including those who might receive little to no protection from vaccines or prior COVID-19 infection, such as those with suppressed immune systems.
These vulnerable populations may need added defence or more immediate protection than vaccines can provide, e.g., those with weakened immune systems, sub-optimal vaccine response, those that require immediate protection, highrisk patients with increased risk of exposure due to work or living situations.
The need for targetted prophylaxis will still be there even if we have multiple effective vaccines. There is also the need for treatment of both outpatients and sicker, hospitalised patients.
Evusheld showed robust, long-lasting protection against symptomatic COVID-19 that continues for at least six months, as demonstrated in the Provent phase-III trial. In Provent, it reduced the risk of developing symptomatic COVID-19 by 77 per cent at the primary analysis and 83 per cent at a six-month analysis compared to placebo.
In the Tackle phase-III outpatient treatment trial, it reduced the risk of developing severe COVID-19 or death (from any cause) by 50 per cent compared to placebo in non-hospitalised patients with mild-to-moderate COVID-19 who had been symptomatic for seven days or less (the primary endpoint), 67 per cent when patients were treated within five days of symptoms, and 88 per cent when treated within three days. Ninety per cent of Tackle participants were at high risk for developing severe COVID-19.
Can this antibody cocktail be used as a third dose for people of all age groups?
Evusheld may offer added protection to a range of different groups where there is currently an unmet need, including those who, it may not be possible to vaccinate, for example, those with allergies or other intolerance of the vaccines; and those who have an inadequate response to vaccines, for example, the immunocompromised.
Most US guideline recommendations, including those put forth by the National Institutes of Health (NIH), are aligned to the US FDA EUA indication/fact sheet and are largely supported by Provent results.
This vaccine is developed for immunocompromised patients. When do you think it can hit the Indian market?
Regulatory dossiers are being compiled as per the requirements of various countries, including India. We are sharing this emerging therapeutic option as evidence generated with stakeholders and seeking their insights to arrive at our strategy, regulatory filing and timelines.
Further plans regarding the dissemination of this LAAB? Which all markets do you intend to cater to in the upcoming days?
AstraZeneca is in discussions with several markets on agreements for Evusheld now that data from Provent has demonstrated AZD7442 can significantly reduce the risk of developing COVID-19. Based on available near-term supply and ongoing discussions, we are prioritising discussions with markets and regions where there is demonstrated interest and clear unmet need and early access mechanisms in place.