We seek to develop an ultra-fast insulin analog formulation for the treatment of diabetes mellitus. An ultra- fast pharmacokinetic/dynamic (PK/PD) profile promises to enable superior performance of pump therapy (continuous subcutaneous insulin infusion) with enhanced safety and more robust integration with glucose- sensing technologies. Ultra-fast kinetics would also facilitate post-prandial glycemic control following meal- time injections. An innovative structural approach is proposed based on non-standard mutagenesis of the insulin molecule. The current barrier to more rapid subcutaneous absorption is the rate of disassembly of the zinc insulin hexamer. This rate is controlled by the stability of an anti-parallel b-sheet at the dimer interface of the hexamer. Partial progress towar accelerated disassembly following subcutaneous injection was achieved in the 1990s by conventional site-directed mutagenesis at the periphery of this b-sheet. Insulin aspart (the activecomponent of NovologR; Novo-Nordisk) and insulin lispro (the active component of HumalogR; Eli Lilly) contain such partially destabilizing mutations (ProB28.Asp in Novolog; ProB28.Lys and LysB29.Pro in Humalog ('KP')). Because their designs were limited by the conventional mutagenesis technologies available in the 1990s, however, neither of these products could fully exploit structural strategies to promote disassembly of the core b-sheet in the insulin hexamer. The core b-sheet of the insulin hexamer is remarkable for the confluence of 8 conserved aromatic rings (TyrB16, PheB24, PheB25, TyrB26, and their dimer-related mates). The thermodynamic and kinetic stability of this classical interface is regulated by an intricate seriesof aromatic-aromatic interactions. We have discovered that the substitution of PheB24 by its non-aromatic analog cyclohexanylalanine (Cha) is compatible with native- like structure and function, but markedly enhances the rate of disassembly of KP-insulin. We therefore propose to synthesize and characterize ChaB24-KP-insulin and ChaB24-AspB28-insulin (as candidate ultra-rapid zinc insulin analog formulations) to obtain improved versions of respective current products HumalogR and NovoR. Dr. B. Frank (principal investigator) was co-inventor of HumalogR during his prior career at Eli Lilly. Thermalin Diabetes, LLC has an exclusive license to ChaB24-related IP, which is owned by CWRU.
By manipulating the aromatic rings on the side chain of an amino acid within the insulin molecule; we can induce accelerated disassembly of the insulin hexamer and speed-up absorption by the body. We have used this principal in Cyclolog-1 and Cyclolog-2; which promise to be ultra-rapid acting and provide better glycemic control and reduced diabetes-related complications relative to other fast-acting analogs currently in use or development. This project will complete feasibility testing on Cyclolog-1 and Cyclolog-2.
