The Centers for Medicare and Medicaid Services (CMS) is proposing a new Part D access rule for immunosuppressants and antidepressants that would no longer require every drug in every class to have a place on the formulary, BioCentury reports. These two drug classes have been part of what’s considered a protected class in Medicare Part D, a category which includes anticonvulsants, antineoplastics, antipsychotics and antiretrovirals.

The proposed rule says the remaining four classes would still be protected. The proposed change could give payers more leverage in rebate negotiations with pharmaceutical firms—insurers have claimed, the rule notes, that the protected status means companies have no incentive to lower prices because the current rule secures Part D formulary status.