Regeneron said on Nov. 30 that its COVID-19 antibody drug cocktail could lose effectiveness against Omicron, providing further indication that the arsenal of medical products developed to fight the disease may need modification to be effective against the new strain. The drugmaker said in a statement (pdf) that early tests show that the high number of mutations in Omicron indicate that “there may be reduced neutralization activity of both vaccine-induced and monoclonal antibody conveyed immunity.” Regeneron President and Chief Scientific Officer, George Yancopoulos, told The Wall Street Journal that the full picture of the efficacy of the company’s antibody treatment against the new variant will only be known in several weeks, after more tests. It comes as researchers have raised doubts about the efficacy of COVID-19 therapeutics and vaccines that target the virus’ spike protein, as Regeneron’s product does, since Omicron has been found to have multiple mutations of the …