Anagliptin

Table 1. Basic profile of anagliptin

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Table 2. Chemical and physical properties (PubChem).

*Note: Predicted values may slightly vary from source to source. 

Anagliptin, is an orally active, antidiabetic drug that works by inhibiting the enzyme dipeptidyl peptidase-4 (DPP-4) (Kato et al., 2011). In response to food intake, endocrine cells in the gastrointestinal tract release incretin hormones, GLP-1 and GIP, to stimulate insulin secretion. Normally, DPP-4 degrades the incretin hormones within a few minutes of their release, thereby playing a key role in regulating the duration of incretin hormone function. Anagliptin, like sitagliptin, is a non-substrate-like inhibitor of DPP-4. By blocking DPP-4 enzymatic activity, anagliptin increases the half-life of incretin hormones, which in turn stimulates increased secretion of insulin by pancreatic β-cells and reduces secretion of glucagon by pancreatic α-cells. Collectively, these functions lower blood glucose levels. Since incretins are only released by the small intestine after eating, DPP-4 inhibitors typically do not induce hypoglycemia (Aschner et al., 2006). 

 Learn more about DPP-4 here.

Each molecule of the DPP-4 enzyme is a transmembrane glycoprotein made up of 766 amino acids and consists of five regions:

• a cytoplasmic region (residues 1–6) not crystallized/not shown
• a trans-membrane region (residues 7–28) not crystallized/not shown
• a highly-glycosylated region (residues 29–323) colored cyan
• a cysteine-rich region (residues 324–551) colored pink
• a catalytic region (residues 552–766) colored orange

The overall structure of the extracellular portion of the enzyme, showing the highly glycosylated, cysteine-rich, and catalytic regions can be seen in Figure 2.

Figure 2. Overall structure of human DPP-4 monomer, complexed with anagliptin. The enzyme is shown in ribbon representation highlighting the N- and C-termini, and various regions of the protein - cysteine-rich region (pink), highly glycosylated region (cyan) and catalytic domain (orange). Anagliptin is shown in a ball-and-stick representation (PDB ID: 3wqh; Watanabe et al., 2015).

The DPP-4 enzyme functions as a dimer, composed of two copies of the same protein (Figure 3).Anagliptin is a non-substrate-like inhibitor of DPP-4. It does not mimic the DPP-4 substrates, but binds to DPP-4 through non-covalent interactions. In this class of inhibitors, an aromatic or proline-like group usually occupies the S1 hydrophobic sub-pocket of the active site of DPP-4 (Figure 3).

Figure 3. X-ray crystal structure of the DPP-4 dimer (ribbons) with bound anagliptin (ball-and-stick). The DPP-4 monomer on the right is color-coded by region as in Figure 2 and the monomer on the left is shown as a grey ribbon (PDB ID: 3wqh; Watanabe et al., 2015). Surface of the active site of DPP-4 is shown in the inset. Anagliptin is shown in a ball-and-stick representation, color-coded by atom type (C: gray; N: blue; O: red). Selected residues in the active sites are shown in the stick figure representation. 

 
Closer examination of the co-crystal structure of DPP-4 and anagliptin (PDB entry 3wqh, Watanabe et al., 2015) reveals the interactions of the drug with its pharmacological target, DPP-4 (Figure 4). While anagliptin does not covalently bind to Ser630 of DPP-4, a dipole interaction occurs between Ser630 and the cyano group of anagliptin. One end of anagliptin, the cyanopyrrolidine group, binds to the S1 subsite and it surrounded by several tyrosines, including Tyr662. The amino group of the drug, in the middle of the molecule, participates in hydrogen bonding with Glu205 and Glu206. The adjacent carbonyl group forms a hydrogen bond with Arg358 while the pyrazolopyrimidine group has π-stacking interactions with Phe357. Together, these interactions account for the tight binding of anagliptin with DPP-4 (IC₅₀ < 4 nm).

Figure 4. Hydrogen bonding interactions (green lines) between anagliptin (ball-and-stick) and active site residues (stick figures) (PDB ID: 3wqh; Watanabe et al., 2015).	Figure 5. Hydrogen bonding interactions (green lines) between Diprotin A (ball-and-stick) and active site residues (sticks figures) (PDB ID: 1nu8; Thoma et al., 2003).

Comparison of the co-crystal structures of DPP-4 with anagliptin (PDB ID 3wqh, Figure 4) and DPP-4 with its substrate, Diprotin A (Ile-Pro-Ile), (PDB ID 1nu8, Figure 5) reveals that anagliptin acts by occluding the DPP-4 active site and prevents binding of incretin hormones.

Table 3. Pharmacokinetics: ADMET of anagliptin

Anagliptin is metabolized by a series of cytochrome p450 enzymes. During its metabolism, anagliptin undergoes a hydrolysis reaction involving the cyano group, which converts it into a carboxylate metabolite (Furuta et al., 2013). Approximately 50% of the drug administered, moves through the human body without being metabolized (Furuta et al., 2013). The drug and its metabolite are cleared from the body through both the digestive and urinary tracts -  ~90% through the urinary system and the remnants along with fecal matter (Furuta et al., 2013).

Concomitant administration of anagliptin and miglitol, an α-glucosidase inhibitor, improved glycemic control and increased the postprandial level of active GLP-1 in Japanese patients with type 2 diabetes (Kim and Kaku, 2012). This suggests that combination therapy with these two drugs would effective. 

The only side effects of anagliptin are on-target ones, including hypoglycemia and constipation (Park, 2013). As this drug increases the concentration of insulin in the body, it runs the risk of inducing hypoglycemia, when taken in combination therapy with medications such as α-glucosidase inhibitors and sulfonylureas. Additionally, because the drug also influences the activity of digestive hormones, constipation is another predictable side effect. The off-target side effects can be broken into two categories: minor and severe. The primary minor off-target side effect is a mild rash (Park, 2013). Meanwhile, the major off-target side effects include intestinal obstructions and severe abdominal pain (Park, 2013).

Table 4. Drug interactions and side effects of anagliptin

Anagliptin was co-developed and co-marketed as Suiny® by Sanwa Kagaku Kenkyusho and Kowa as an antidiabetic treatment therapy for type 2 diabetes (“Anagliptin”). It underwent a double-blind Phase III clinical trial sponsored by JW Pharmaceuticals.  The purpose of the study was to evaluate the safety and efficacy of anagliptin at 2 dosages, compared with placebo in type 2 diabetic patients. The trial took place at Kangbuk Samsung Hospital in South Korea, involved 117 participants, between May 2011 and September of 2012 (Park, 2013).

Anagliptin was approved by Pharmaceuticals and Medical Devices Agency of Japan (PMDA) on September 28, 2012, and is prescribed as an oral tablet containing either 100 or 200 mg (Park, 2013). This drug has not yet been approved for use in the United States by the US FDA.

Table 5. Links to relevant resources

Anagliptin. Pharmacodia. http://www.pharmacodia.com/yaodu/html/v1/chemicals/635440afdfc39fe37995fed127d7df4f.html

Anagliptin. Pubchem.ncbi.nlm.nih.gov. https://pubchem.ncbi.nlm.nih.gov/compound/Anagliptin

Anagliptin, Suiny. Chemblink.com. http://www.chemblink.com/products/739366-20-2.htm

Aschner, P., Kipnes, M. S., Lunceford, J. K., Sanchez, M., Mickel, C., and Williams-Herman, D. E. (2006) Effect of the Dipeptidyl Peptidase-4 Inhibitor Sitagliptin as Monotherapy on Glycemic Control in Patients with Type 2 Diabetes. Diabetes Care 29, 2632-2637. doi: 10.2337/dc06-0703

Ervinna, N., Mita, T., Yasunari, E., Azuma, K., Tanaka, R., Fujimura, S., Sukmawati, D., Nomiyama, T., Kanazawa, A., Kawamori, R., Fujitani, Y., and Watada, H. (2013) Anagliptin, a DPP-4 Inhibitor, Suppresses Proliferation of Vascular Smooth Muscles and Monocyte Inflammatory Reaction and Attenuates Atherosclerosis in Male Apo E-Deficient Mice. Endocrinology 154, 1260-1270. doi: 10.1210/en.2012-1855

Furuta, S., Smart, C., Hackett, A., Benning, R., and Warrington, S. (2013) Pharmacokinetics and Metabolism of [¹⁴C]Anagliptin, a Novel Dipeptidyl Peptidase-4 Inhibitor, in Humans. Xenobiotica 43, 432-442. doi: 10.3109/00498254.2012.731618

Kato, N., Oka, M., Murase, T., Yoshida, M., Sakairi, M., Yamashita, S., Yasuda, Y., Yoshikawa, A., Hayashi, Y., Makino, M., Takeda, M., Mirensha, Y., and Kakigami, T. (2011) Discovery and Pharmacological Characterization of N-[2-({2-[(2S)-2-Cyanopyrrolidin-1-Yl]-2-Oxoethyl}Amino)-2-Methylpropyl]-2-Methylpyrazolo[1,5-A]Pyrimidine-6-Carboxamide Hydrochloride (Anagliptin Hydrochloride Salt) as a Potent and Selective DPP-IV Inhibitor. Bioorganic & Medicinal Chemistry 19, 7221-7227. doi: 10.1016/j.bmc.2011.09.043

Kim. H., and Kaku, K. (2012) Drug Interaction between Anagliptin, a Novel Dipeptidyl Peptidase-4 Inhibitor, and Miglitol, an α-glucosidase Inhibitor, in Japanese Patients with Type 2 Diabetes. Japan Pharmacology & Therapeutics 40, 871–881.

May, M., and Schindler, C. (2016) Clinically and pharmacologically relevant interactions of antidiabetic drugs. Therapeutic Advances In Endocrinology And Metabolism 7, 69-83. doi: 10.1177/2042018816638050

Nakamura, Y., Hasegawa, H., Tsuji, M., Udaka, Y., Mihara, M., Shimizu, T., Inoue, M., Goto, Y., Gotoh, H., Inagaki, M., and Oguchi, K. (2015) Diabetes Therapies in Hemodialysis Patients: Dipeptidase-4 Inhibitors. World Journal of Diabetes 6, 840. doi: 10.4239/wjd.v6.i6.840

Park, S. W. (2013) A Study to Efficacy and Safety of CWP-0403 in Type 2 Diabetes Mellitus Patients - ClinicalTrials.gov. Clinicaltrials.gov. https://clinicaltrials.gov/ct2/show/NCT01529528

Thoma, R., Loffler, B., Stihle, M., Huber, W., Ruf, A., and Hennig, M. (2003) Structural basis of proline-specific exopeptidase activity as observed in human dipeptidyl peptidase-IV. Structure 11, 947-959.  doi: 10.1016/S0969-2126(03)00160-6

Watanabe, Y. S., Yasuda, Y., Kojima, Y., Okada, S., Motoyama, T., Takahashi, R., and Oka, M. (2015) Anagliptin, a Potent Dipeptidyl Peptidase IV Inhibitor: its Single-Crystal Structure and Enzyme Interactions. Journal of Enzyme Inhibition and Medicinal Chemistry 30, 981-988. doi: 10.3109/14756366.2014.1002402