If an expected HHS proposed rule on rebates and safe harbors under the anti-kickback statute portends a significant change to PBMs’ business model, experts predict the administration would face legal challenges. Officials who know details of the proposal’s contents have kept mum, but available information indicates that it would make economically significant changes to the current rebate system for plans and pharmacy benefit managers. The proposal has languished at the White House Office of Management and Budget for the past...