(Bloomberg) -- The antibody drugs GSK Plc and Regeneron Pharmaceuticals Inc. developed against Covid don’t appear to work for omicron and its subvariants, a panel of experts advising the World Health Organization said, recommending against the use of the medicines.

The group’s decision comes amid “evidence from laboratory studies that these drugs are not likely to work against currently circulating variants,” the panel said in the medical journal BMJ Friday.

The new guideline is a blow to Regeneron, GSK and its partner Vir Biotechnology, replacing a conditional endorsement of the treatments with a “strong recommendation” against their use. But it’s not entirely surprising: GSK and Vir’s sotrovimab had already lost its US authorization in April because the therapy was unlikely to work against the dominant omicron BA.2 subvariant. 

GSK said in a statement that it’s disappointed with the WHO recommendation against its Covid antibody therapy and it continues to look for real world evidence on the drug’s effectiveness.

Regeneron said the US Food and Drug Administration in January had excluded the use of its Covid antibody cocktail in regions where infections were caused by newer variants, and that the treatment hasn’t being used anywhere in the US for some time. The company, meanwhile, is working on “next generation” antibodies that can work against current and future variants.

The WHO panel of more than 60 international experts also backed Gilead Sciences Inc.’s remdesivir -- one of the medicines used at the start of the pandemic -- for patients with severe Covid, in addition to the prior recommendation for non-severe cases. The drug still shouldn’t be used for critical cases, they said.

(Corrects recommended use of remdesivir in last paragraph of story originally published Sept. 16.)

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