OSI-420 is the active metabolite of Erlotinib (EGFR inhibitor with IC50 of 2 nM).
Description :
OSI-420 (Desmethyl Erlotinib, CP-473420) is an active metabolite of erlotinib, which is a potent EGFR tyrosin kinase inhibitor for treatment of NSCLC.
Desmethyl Erlotinib exposure (AUC) in plasma is 30% (range 12-59%) of erlotinib, and Desmethyl Erlotinib clearance is more than 5-fold higher than erlotinib. The CSF penetration of erlotinib and Desmethyl Erlotinib is <5% relative to total plasma concentration[1].
OSI-420 is the major metabolite of Erlotinib in human plasma. Erlotinib disappearance from plasma after a short IV infusion is biexponential with a mean terminal half-life of 5.2 h and a mean clearance of 128 ml/min per m(2). OSI-420 exposure (AUC) in plasma is 30% (range 12-59%) of erlotinib, and OSI-420 clearance is more than 5-fold higher than erlotinib. Erlotinib and OSI-420 are equipotent, and the combined concentrations of erlotinib + OSI-420 achieved in the CSF exceeded the IC50 (7.9 ng/ml or 20 nM) for the EGFR tyrosine kinase inhibition in intact tumor cells. [1] Erlotinib potently inhibits EGFR activation in intact cells including HNS human head and neck tumor cells (IC50 20nM), DiFi human colon cancer cells andMDA MB-468 human breast cancer cells. Erlotinib (1 μM) induces apoptosis in DiFi human colon cancer cells. [2] Erlotinib inhibits growth of a panel of NSCLC cell lines including A549, H322, H3255, H358 H661, H1650, H1975, H1299, H596 with IC50 ranging from 29 nM to >20 μM. [3] Erlotinib(2 μM) significantly inhibits growth of AsPC-1 and BxPC-3 pancreatic cells. [4] The effects of Erlotinib HCl in combination with gemcitabine are considered additive in KRAS-mutated pancreatic cancer cells. Ten micromolar of Erlotinib inhibits EGFR phospho-rylation at the Y845 (Src-dependent phosphorylation) and Y1068 (auto-phosphorylation) sites. [5] Combination with Erlotinib could down-modulate rapamycin-stimulated Akt activity and produces a synergistic effect on cell growth inhibition. [6]
At doses of 100 mg/kg, Erlotinib completely prevents EGF-induced autophosphorylation of EGFR in human HN5 tumors growing as xenografts in athymic mice and of the hepatic EGFR of the treated mice. [1] Erlotinib reduces the growth of xenografted human AML cells. [4]