Insurance coverage of medical foods for treatment of inherited metabolic disorders

Inherited metabolic disorders (IMDs) are a complex group of genetic conditions in which an enzyme deficiency prevents normal metabolism. When the enzyme deficiency prevents normal use of nutrients, effective treatment of the associated IMD depends primarily on dietary restriction because use of off-the-shelf foods containing substances that cannot be metab-olized by the affected person results in toxic effects. Typically, a health-care provider prescribes a specialized diet restricting the food component that cannot be metabolized. For example, individuals affected with phenylketonuria are unable to prop-erly metabolize the amino acid phenylalanine, which must be selectively limited in their diet to prevent severe intellectual disability. For some disorders, food products restricted in the offending material are available without modification of con-ventional products, e.g., galactosemia is treated in infancy by conventional formulas using sucrose as a sugar source rather than the galactose-containing disaccharide, lactose. For oth-ers, particularly disorders of amino acid metabolism, conven-tional products that restrict the offending amino acid(s) are not available. Treatment of disorders of amino acid metabolism requires products specially manufactured to exclude an offend-ing amino acid or amino acids. These are typically supplied in powdered formula or in other product forms such as bars, cap-sules, or ready-to-consume liquids. Beyond powdered formu-las, bars, and capsules, physicians can also prescribe modified low-protein foods: products specially manufactured to provide versions of common foods made with restricted protein con-tent. Such preparations are referred to collectively as “medi-cal foods,” defined by the US Food and Drug Administration in section 5(b) of the Orphan Drug Act (21U.S.C. 360ee (b) (3)) as “food which is formulated to be consumed or adminis-tered enterally under the supervision of a physician and which is intended for specific dietary management of the disease or condition for which distinctive nutritional requirements, based on recognized scientific principles, are established by medical evaluation.”