Dasatinib

spinqualitylabelsall models Dasatinib, also known as Sprycel (2gqg) Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

Better Known as: Sprycel

• Marketed By: Bristol-Myers Squibb
• Major Indication: Chronic Myelogenous Leukemia (CML)
• Drug Class: Receptor Tyrosine Kinase (Especially, PDGFR, KIT & BCR-Abl) Inhibitor
• Date of FDA Approval (Expiration): 2006 (2020)
• 2009 Global Sales: $421 Million
• Importance: It is a second generation receptor Tyrosine kinase inhibitor. It binds to Abl with less stringent conformational requirements so it exhibits increased potency compared to Imatinib although with less selectivity. Unlike most RTK inhibitors, Dasatinib binds the active conformation of BCR-Abl. Is used to treat patients with certain Imatinib resistant forms of CML. Controversial due to its nearly $50,000 per year cost.
• See Pharmaceutical Drugs for more information about other drugs and disorders

Mechanism of Action

Chronic Myelogenous Leukemia (CML) results from a gene defect in a haematological stem cell, . Compared to the tightly regulated c-Abl kinase, BCR-Abl has a truncated auto-regulatory domain, leading to constitutive activation of its tyrosine kinase activity. The result of this nearly limitless activation is unregulated phosphorylation of downstream receptors leading to uncontrolled growth and survival of leukemic cells. Like many other receptor tyrosine kinases, BCR-Abl is at an equilibrium between two states, an active state and an auto-regulated inactive state. Dasatinib functions by binding in the ATP site of the active conformation of BCR-Abl. This is unique as Abl inhibitors like Imatinib and Nilotinib bind only the inactive conformation. The well known in the Dasatinib bound BCR-Abl, with the so-called extending away from the ATP binding site & covering the top of the ATP binding site. A critically important residue, Thr 315, is known as , forms a . In other kinases like B-Raf, p38 & KDR, position 315 is occupied by a larger residue that is not conducive to Dasatinib binding, giving Dasatinib its high specificity. A number of point mutations within BCR-Abl result in Imatinib resistance. There are 15 well known Imatinib resistance conferring mutations at positions like 244, 250, 252, 253, 315, 317, 351, and 396. Dasatinib has shown effectiveness with nearly all Imatinib resistant versions of BCR-Abl, with the exception of the T315I/A & T317L/V mutants. In BCR-Abl, by H-bonds to residues Met 318 an Thr 315, along with hydrophobic interactions with residues Ala 380, Leu 370, Met 290, Gly 321, Thr 319, Ala 269, Phe 317, Glu 316, Lys 271, Ile 313, Val 299 & Glu 286, stabilizing the inhibited conformation of the kinase.

Pharmacokinetics

Tyrosine Kinase Inhibitor Pharmacokinetics VEGFR & KIT Inhibitors EGFR Inhibitors BCR-Abl Inhibitor Parameter Sunitinib (Sutent) Sorafenib (Nexavar) Erlotinib (Tarceva) Gefitinib (Iressa) Lapatinib (Tykerb) Imatinib (Gleevec) Nilotinib (Tasigna) Dasatinib (Sprycel) Tmax (hr) 8 8.3 2.0 5.4 4 3.7 3.0 1.0 Cmax (ng/ml) 24.6 460 69.6 130 115 2070 411 124 Bioavailability (%) Variable 29-49 99 59 Variable 98 30 20 Protein Binding (%) 95 99 93 90 99 95 98 96 T1/2 (hr) 83 29 9.4 26.9 9.6 26.6 16.0 3.3 AUC (ng/ml/hr) 1921 11040 20577 3850 1429 4760 10052 461 Dosage (mg) 50 50 150 250 100 400 200 200 Metabolism Hepatic (CYP3A4) Hepatic (CYP3A4) Hepatic (CYP3A4) Hepatic (CYP3A4) Hepatic (CYP3A4) Hepatic (CYP3A4) Hepatic (CYP3A4) Hepatic (CYP3A4) For Pharmacokinetic Data References, see: References