NEW YORK —

Representative Chris Collins, one of President Trump’s earliest and most vocal supporters, was charged with insider trading Wednesday. The Republican from upstate New York was accused of tipping off his son and others to sell stock in an Australian pharmaceutical company before the results of one of its failed drug tests became public, federal prosecutors said.

The charges against Collins stem from his involvement with Innate Immunotherapeutics Ltd., a drug maker based in Sydney whose primary business was the research and development of a medication designed to treat a form of multiple sclerosis, according to an indictment.