AstraZeneca's Covid-19 antibody jab approved for adults medically unsuitable for vaccination: HSA

SINGAPORE — The Health Sciences Authority (HSA) on Monday (Aug 1) granted interim authorisation for AstraZeneca's Covid-19 antibody drug for adults who are medically unsuitable for vaccination against the coronavirus.

The Evusheld treatment comprises two monoclonal antibodies and is administered via intramuscular injection.

HSA said the treatment is approved for the prevention of Covid-19 in adults who have not had a known recent exposure to someone infected with the disease and are unlikely to mount an adequate immune response to Covid-19 vaccination.

This may be due to their immunocompromised state from a medical condition or from receiving immunosuppressive medications or treatments.

Such medical conditions or treatments include those who are in an immunocompromised state from organ, blood or bone marrow transplants, immune deficiencies, human immunodeficiency virus (HIV) infections, as well as the use of corticosteroids or other immunosuppressive medicines.

The Evusheld jab is not a substitute for vaccination in individuals for whom the Covid-19 vaccine is recommended, said HSA.

"The treatment must be prescribed by a doctor and the suitability of use on the individual patient will require a careful clinical assessment by the prescribing doctor."

"RELATIVE RISK REDUCTION"

HSA said the drug's efficacy data was based on an ongoing Phase 3 study in more than 5,000 participants aged 18 to 99.

The participants were all unvaccinated and either had risk factors for inadequate Covid-19 vaccination response or increased risk for coronavirus infection.

Results showed that there was a "relative risk reduction" of symptomatic Covid-19 illness by 77 per cent with Evusheld compared to a placebo, with a duration of protection of about six months for non-Omicron variants of the Sars-CoV-2 virus.

"At the time the clinical study was conducted, the circulating variants of concern included Alpha, Beta, Gamma, and Delta," said HSA.

Recent in-vitro data showed that certain Omicron subvariants are less susceptible to Evusheld, hence the duration of protection against the subvariants is currently unknown, HSA added.

According to Reuters, the lab-made antibodies in Evusheld are designed to linger in the body for months to contain the virus in case of an infection.

HSA said safety data also showed that the drug was "well-tolerated" and the incidence of adverse events reported in the clinical study were generally low.

Common adverse events reported were mild to moderate in severity, and included headache, throat pain, runny nose, nasal congestion and muscle pain.

"While the study reported a higher incidence of cardiovascular adverse events with Evusheld, the causal relationship has not been established based on current available data," said HSA, adding that it will continue to closely monitor for any "further cardiovascular safety signal".

The available clinical evidence "preliminary demonstrated" that Evusheld has a favourable benefit-risk profile for the prevention of Covid-19 in individuals who are unlikely to mount an adequate immune response to the Covid-19 vaccines or for whom Covid-19 vaccination is not recommended.

"Emerging data on Evusheld’s effectiveness against the currently circulating Omicron variant will be required to further determine its continued benefits," said HSA.

As there was no clinical data on pregnant women, breastfeeding mothers and children, no recommendation could be made in these groups, the agency added.

CONTINUOUS REVIEW OF DATA

Evusheld was granted interim authorisation under the Pandemic Special Access Route (PSAR), which facilitates early access to critical novel vaccines, medicines and medical devices during a pandemic.

HSA said it will actively review the evolving effectiveness and safety data to ensure that the benefits of Evusheld continue to outweigh the known risks.

"As a condition for the interim authorisation under PSAR, AstraZeneca is required to collect and submit the relevant safety data from ongoing clinical studies to ensure the continued safety and efficacy of Evusheld, including its efficacy against prevailing variants," it added.

PSAR interim authorisation may be terminated if new data suggest that the benefits of Evusheld no longer outweigh the risks.

"To obtain full registration for Evusheld, AstraZeneca will need to submit the complete dataset based on prevailing international standards." CNA