Section 423.112 - Establishment of prescription drug plan service areas(a)Service area for prescription drug plan sponsors. The service area for a prescription drug plan sponsor other than a fallback prescription drug plan sponsor consists of one or more PDP regions as established under paragraphs (b) and (c) of this section.(b)Establishment of PDP regions -(1)General. CMS establishes PDP regions in a manner consistent with the requirements for the establishment of MA regions as described at § 422.455 of this chapter.(2)Relation to MA regions. To the extent practicable, PDP regions are the same as MA regions. CMS may establish PDP regions that are not the same as MA regions if CMS determines that the establishment of these regions improves access to prescription drug plan benefits for Part D eligible individuals.(c)Authority for territories. CMS establishes a PDP region or regions for States that are not within the 50 States and the District of Columbia.(d)Revision of PDP regions. CMS may revise the PDP regions established under paragraphs (b) and (c) of this section.(e)Regional or national plan. Nothing in this section prevents a prescription drug plan from being offered in two or more PDP regions in their entirety or in all PDP regions in their entirety. 70 FR 4525 , Jan. 28, 2005, as amended at 75 FR 19816 , Apr. 15, 2010