The coalition said in a letter sent to the FTC Thursday that the deal could reduce access to GLP-1s, and harm competition in development of cell and gene therapies.

U.S. Public Interest Research Group, Service Employees International Union (SEIU) and others expressed concerns in a letter to the FTC about the $16.5 billion deal, which Novo Holdings has said would boost supply of Wegovy, Novo's blockbuster GLP-1 injectable weight-loss drug.

Five U.S. consumer groups and two big labor unions are pushing for the Federal Trade Commission to block Novo Nordisk Foundation's planned $16.5 billion acquisition of Catalent (NYSE:CTLT), arguing that a deal would hurt competition in weigh-loss drugs.