Covid-19: Monoclonal antibodies ineffective against variants

The European Medicines Agency (EMA) warned on Friday that monoclonal antibody treatments are proving ineffective against the increasingly dominant new strains of COVID-19.

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A large number of monoclonal antibodies targeting the spike protein of the virus, given in hospitals by injection or infusion, have helped overcome the peak of the wave.

But, for the EMA, they are “no longer effective against new strains” or variants.

Laboratory tests have shown that they are “not very effective against Omicron BA.4.6, BA.2.75.2 and XBB types,” the press release of the European agency in The Hague underlined.

“They failed to significantly neutralize BQ.1 and BQ.1.1, which are expected to become dominant strains within the EU in the next few weeks.”

The main antibody-based therapies are Evusheld from AstraZeneca, Ronapreve from Roche and Xevudy from GSK and Vir Laboratories.

The EMA says antiviral treatments such as Paxlovit from Pfizer Laboratories should be effective.

Monoclonal antibodies were initially able to reduce the risk of hospitalization and death by 80%, but became less effective as the virus mutated.

In September, the WHO recommended that Xevudy and Ronapreve be discontinued because they did not work against the new variants.

The EMA approved the Pfizer/BioNTech and Moderna vaccines against BA.4 and BA.5 strains in September and October, respectively.

The regulator clarified on Tuesday that both vaccines can now “be used for primary vaccination”.

While earlier variants like Alpha and Delta will eventually fade away, Omicron and its sub-lines are expected to dominate throughout 2022 and remain at the top in 2023.

In particular, types BA.4 and BA.5 have contributed to an increase in the number of new cases of the disease in Europe and the United States in recent months.

All omicron variants cause slow disease progression because they colonize less in the lungs and more in the upper respiratory tract, causing symptoms such as fever, fatigue, and loss of smell.