Section 11A. (a) For an insured member who (1) is receiving an active course of medical treatment from a health care provider for a serious disease, including but not limited to cancer or cystic fibrosis, that if disrupted in the course of medical treatment would pose an undue hardship to the patient and (2)(i) began this active course of treatment before being enrolled in a reduced or selective network plan where the provider is not part of the reduced or selective network or (ii) began this active course of treatment before being enrolled in a tiered network plan where the provider is in the highest cost-sharing tier, the carrier shall provide coverage for those medically necessary and covered services that are part of that active course of treatment provided by that health care provider, to the extent required by subsection (b).

(b) A carrier to which subsection (a) applies shall cover the health care provider's services for the duration of the active course of treatment during the plan year, if (1) the insured's employer offers the insured only a choice of reduced or selective network plans in which the health care provider is not part of any of the offered reduced or selective networks, or a choice of tiered network plans in which the health care provider is in the highest cost-sharing tier; (2) that health care provider is a comprehensive cancer center, pediatric hospital or pediatric specialty unit as defined in section 1 of chapter 118G; and (3) that health care provider is providing the insured with an active course of medical treatment that is not available from another provider in the network of the insured's plan.

(c) For services provided under this section from a provider that is not in the network of the insured's plan, patient cost-sharing shall be at the lowest cost-sharing level applicable to those services in the plan, and reimbursement shall be based on median in-network rates of the specific health care provider in that carrier's private plans in a manner consistent with data filed by that carrier with the division of health care finance and policy; provided, however, that if the specific health care provider does not participate in any other plan of the carrier, then based on negotiated rates. For services provided under this section by a provider in the highest cost-sharing tier of a tiered network plan, patient cost-sharing shall be based on the second-highest cost-sharing tier in that plan.

(d) The commissioner shall adopt regulations to carry out this section.