In this review article, we discuss the unique PK/PD properties of a novel inhaled formulation, Technosphere® insulin (TI), approved by the U.S. Food and Drug Administration as Afrezza® (insulin human) inhalation powder and inhaler (MannKind Corporation, Westlake Village, CA), that support its use in patient populations with T1D or T2D. This evidence concerns the gene INS and type 1 diabetes mellitus.