Gemigliptin

# Overview
Gemigliptin (rINN), previously identified as LC15-0444, is an oral anti-hyperglycemic agent (anti-diabetic drug) of the new dipeptidyl peptidase-4 (DPP-4) inhibitor class of drugs. It is well known that glucose lowering effects of DPP-4 inhibitors are mainly mediated by GLP-1 and gastric inhibitory polypeptide (GIP) incretin hormones which are inactivated by DPP-4.
Gemigliptin was initially developed solely by LG Life Sciences. In 2010, Double-Crane Pharmaceutical Co. (DCPC) joined with LGLS to co-develop the final compound and collaborate on the marketing of the drug in China. LGLS also announced on Nov., 2010 that NOBEL Ilac has been granted rights to develop and commercialize gemigliptin in Turkey.
A New Drug Application (NDA) for gemigliptin in the treatment of type 2 diabetes was submitted to the Korea Food & Drug Administration (KFDA) in July 2011. Then on June 27, 2012, the KFDA has approved the manufacture and distribution of LG Life Sciences diabetes treatment, Zemiglo, the main substance of which is gemigliptin. Clinical trials for evaluating the safety and efficacy of gemigliptin in combination with metformin have been completed.

# History
The NDA for gemigliptin was submitted to KFDA in July, 2011 and it was approved on June 27, 2012.
By the end of 2012, gemigliptin will be marketed in Korea as Zemiglo which is the fifth new DPP-4 inhibitor diabetes treatment in the world.

# Mechanism of action
DPP-4 is a serine protease located on the cell surfaces throughout the body. In plasma, DPP-4 enzyme rapidly inactivates incretins including GLP-1 and GIP which are produced in the intestine depending on the blood glucose level and contribute to the physiological regulation of glucose homeostatis. Active GLP-1 and GIP increase the production and release of insulin by pancreatinc beta cells. GLP-1 also reduces the scretion of glucacon by pancreatic alpha cells, thereby resulting in a decreased hepatic glucose production. However these incretins are rapidly cleaved by DPP-4 and their effects last only for a few minutes. DPP-4 inhibitors block the cleavage of the gliptins and thus lead to an increasee insulin level and a reduced glucagon level in a glucose-dependent way. This results in a decrease of fasting and postprandial glycemia, as well as HbA1c levels.

# Preclinical studies
Gemigliptin is a competitive, reversible DPP-4 inhibitor (IC50 = 16 nM) with excellent selectivity over other critical human proteases such as DPP-2, DPP-8, DPP-9, elastase, trypsin, urokinase and cathepsin G. Gemigliptin was rapidly absorbed after single oral dosing and the compound was eliminated with a half-life of 3.6 h, 5.2 h, and 5.4 h in the rat, dog, and monkey, respectively.
The bioavailability of gemigliptin in the rat, dog, and monkey was species-dependent with the values of 94%, 73%, and 26%, respectively. Following the oral administration of gemigliptin in the rat, dog and monkey, about 80% inhibition of plasma DPP-4 activity were observed at the plasma levels of 18 nM, 14 nM and 4 nM, respectively.
In the diet-induced obese (DIO) mice, gemigliptin reduced glucose excursion during OGTT in a dose dependent manner with the minimum effective dose of 0.3 mg/kg and enhanced glucose-stimulated plasma GLP-1 increase in a dose dependent manner reaching the maximum effect at the dose of 1 mg/kg.
Following 4 week oral repeat dosing in the DIO mice, gemigliptin reduced significantly HbA1c with the minimum effective dose of 3 mg/kg. In the beagle dog, gemigliptin significantly enhanced active GLP-1, decreased glucagon, and reduced glucose excursion during OGTT following a single dosing.
Studies on animals suggest its positive effect on hepatic and renal fibrosis
. Data on human patients are still inconclusive

# Clinical studies
The dose-range finding phase 2 study was performed and 145 patients (91men and 54 women) with type 2 diabetes mellitus were enrolled. All three doses (50,100 and 200 mg groups) of gemigliptin significantly reduced the HbA1c from baseline compared to the placebo group without a significant difference between the doses.
Subjects with a higher baseline HbA1c (8.5%) had a greater reduction in HbA1c. Insulin secretory function, as assessed using homeostasis model assessment-beta cell, C-peptide and the insulinogenic index, improved significantly with gemigliptin treatment. Insulin sensitivity, as assessed using homeostasis model assessment-insulin resistance, also improved significantly after 12 weeks of treatment.
The 50 and 200 mg groups had significantly reduced total cholesterol and low-density lipoprotein cholesterol levels at 12 weeks compared to the placebo group.
The incidences of adverse events were similar in all study subjects. Gemigliptin monotherapy (50 mg for 12 weeks) improved the HbA1c, FPG level, oral glucose tolerance test results, -cell function and insulin sensitivity measures, and was well tolerated in subjects with type 2 diabetes.
Results of Phase 3 clinical trials which have been finished recently will be updated near future.