Medicare supplement policies; annual open enrollment period. Requires an insurer, health services plan, or health maintenance organization issuing Medicare supplement policies or certificates in the Commonwealth to offer to an individual currently insured under any such policy an annual open enrollment period commencing on the day of the individual's birthday and remaining open for at least 60 days thereafter, during which time the individual may purchase any Medicare supplement policy made available by any insurer in the Commonwealth that offers the same benefits as or lesser benefits than those provided by the current coverage. The bill also requires such insurer, health services plan, or health maintenance organization to notify, at least 15 days but not more than 30 days prior to the commencement of such annual open enrollment period, each individual to whom such open enrollment period applies of the dates of that open enrollment period, the rights of the individual during that open enrollment period, and any modification of benefits provided by or adjustment of premiums charged for such Medicare supplement policy.