Seven GOP Senate Finance members wrote a letter to HHS Secretary Kathleen Sebelius and CMS Administrator Don Berwick suggesting that due to the outpouring of concern from the provider community — including key health care integrated systems such as the Mayo Clinic, Billings Clinic, Intermountain Healthcare and Cleveland Clinic — CMS officials should pull the regulation and rewrite it so that ACOs can deliver on their promise of real reform.

“In principle, the model of an ACO still holds promise,” the senators wrote. “An ACO model that can increase provider coordination and patient accountability would be a step in the right direction compared with today’s fragmented delivery system. However, it is increasingly clear this proposed rule missed the target.”

The letter does not mention the “pioneer” ACO demo that CMS launched last week, which will be run through the Center for Medicare and Medicaid Innovation. The Pioneer program includes two initiatives: One offers opportunities for “more mature” systems to move to population-based — or capitated — payment systems, the other provides advanced payments for providers that want to participate in the ACO shared savings program.

The letter was signed by Sens. Tom Coburn (OK), Mike Enzi (WY), Richard Burr (NC), Jon Kyl (AZ), Pat Roberts (IS), Mike Crapo (ID) and John Cornyn (TX).