On Tuesday, a group of physicians from around the nation traveled to Washington, D.C., intending to demand that the Health and Human Services Department immediately stop the Medicare experiment, which is known as direct contracting.

The doctors were denied the right to present HHS with a petition signed by more than 1,500 physicians who believe the direct contracting pilot threatens “the future of Medicare as we know it.”

Advocates have been publicly sounding the alarm about the program for months, warning that it could fully hand traditional Medicare over to Wall Street investors and other profit-seekers, resulting in higher costs for patients and lower-quality care.