The therapeutic success of interventions targeting glucokinase (GK) activation for the treatment of type 2 diabetes has been limited by hypoglycemia, steatohepatitis, and loss of efficacy over time. The clinical characteristics of patients with GK-activating mutations or GK regulatory protein (GKRP) loss-of-function mutations suggest that a hepatoselective GK activator (GKA) that does not activate GK in β cells or affect the GK-GKRP interaction may reduce hyperglycemia in patients with type 2 diabetes while limiting hypoglycemia and liver-associated adverse effects. Here, we review the rationale for TTP399, an oral hepatoselective GKA, and its progression from preclinical to clinical development, with an emphasis on the results of a randomized, double-blind, placebo- and active-controlled phase 2 study of TTP399 in patients with type 2 diabetes. In this 6-month study, TTP399 (800 mg/day) was associated with a clinically significant and sustained reduction in glycated hemoglobin, with a placebo-subtracted least squares mean HbA1c change from baseline of −0.9% (P < 0.01). Compared to placebo, TTP399 (800 mg/day) also increased high-density lipoprotein cholesterol (3.2 mg/dl; P < 0.05), decreased fasting plasma glucagon (−20 pg/ml; P < 0.05), and decreased weight in patients weighing ≥100 kg (−3.4 kg; P < 0.05). TTP399 did not cause hypoglycemia, had no detrimental effect on plasma lipids or liver enzymes, and did not increase blood pressure, highlighting the importance of tissue selectivity and preservation of physiological regulation when targeting key metabolic regulators such as GK.

Increasing evidence supports the role of the Receptor for Advanced Glycation Endproducts (RAGE) in the pathology of Alzheimer’s disease. Azeliragon (TTP488) is an orally bioavailable small molecule inhibitor of RAGE in Phase 3 development as a potential treatment to slow disease progression in patients mild AD. Preclinical studies in animal models of AD (tgAPPSwedish/London) have shown azeliragon to decrease Aβ plaque deposition; reduce total Aβ brain concentration while increasing plasma Aβ levels; decreases sAPPβ while increasing sAPPα; reduce levels of inflammatory cytokines; and slow cognitive decline and improve cerebral blood flow. In the Phase 2b study, 18-months treatment in patients with mild-to-moderate AD indicated a baseline to endpoint change in ADAS-cog of 3.1 points in favor of drug. A greater magnitude of effect was evident in the sub-group of patients with mild AD (MMSE 21-26) with a baseline to endpoint change of 4 points on the ADAS-cog in favor of azeliragon and a 1 point change in CDR-sb in favor of drug. Azeliragon 5 mg/day delayed time to cognitive deterioration (7-point change in ADAS-cog from baseline, logrank p=0.0149). Based on promising results from the Phase 2b study, a Phase 3 registration program (STEADFAST) is being conducted under a Special Protocol Assessment from FDA. The ongoing Phase 3 program, if successful may demonstrate azeliragon can slow cognitive decline in mild AD patients.

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In this paper we report that, compared with term rat neonates, both mitochondrial content and function are diminished in liver of preterm neonates (delivered 24 h before full term) compromising cellular energy provision in the postnatal period. In addition, there is a parallel reduction in the content of mRNAs encoding mitochondrial proteins in preterm rats. Also, efficient oxidative phosphorylation is not attained in these pups until 3 h after birth. Although isolated liver mitochondria from preterm neonates show a two-fold increase in F1-ATPase beta-subunit and cytochrome c oxidase activity 1 h after birth, the abnormal coupling efficiency between respiration and oxidative phosphorylation (ADP/O ratio) is due to maintenance of high H(+)-leakage values in the inner mitochondrial membrane. Postnatal reduction of the H+ leak occurs concomitantly with an increase in intra-mitochondrial adenine nucleotide concentration. Accumulation of adenine nucleotides in preterm and term liver mitochondria parallels the postnatal increase in total liver adenine nucleotides. Delayed postnatal induction of adenine biosynthesis most likely accounts for the lower adenine nucleotide pool in the liver of preterm neonates. The delayed postnatal accumulation of adenine nucleotides in mitochondria is thus responsible for the impairment in oxidative phosphorylation displayed by organelles of the preterm liver.