Daniel Best, the health official overseeing the Trump administration's efforts to lower drug costs, has died, the Department of Health and Human Services announced Thursday.

“It is with tremendous sadness that I learned of the passing of our friend and colleague," HHS Secretary Alex Azar said in a statement. "I had the great privilege to know Dan Best for the past decade. He joined me here at HHS out of a desire to serve the American people by making healthcare more affordable. He brought his deep expertise and passion to this task with great humility and collegiality. All of us who served with Dan at HHS and in the administration mourn his passing and extend our thoughts and prayers to his wife Lisa and the entire Best family at this difficult time.”

The administration did not disclose a cause of death, and HHS said it did not have any additional comments.

Best, a former CVS executive, joined HHS in March 2018 to work on drug pricing policies. Best had served as the corporate vice president of industry relations for CVS Health’s Medicare Part D business, and before that was at Pfizer Pharmaceuticals for 12 years.

When Azar nominated him he said that he had the "deep experience necessary to design and enact reforms to lower the price of medicines that help Americans live healthier and longer lives." Best's job was to advise Azar on drug pricing reform issues.

The administration has rolled out proposals to lower prescription drugs for several months, including requiring drug companies to post the list prices of their products in commercials and allowing Medicare to pay less for treatments administered by doctors. Best on Tuesday wrote a blog post about the proposal to answer questions for the public.

President Trump has said that lowering drug prices is a priority.