ast-1306 and Neoplasms

Allitinib, a novel irreversible selective inhibitor of the epidermal growth factor receptor (EGFR) 1 and human epidermal receptor 2 (ErbB2), is currently in clinical trials in China for the treatment of solid tumors. It is a structural analog of lapatinib but has an acrylamide side chain. Sixteen metabolites of allitinib were detected by ultra-high-performance liquid chromatography/quadrupole time-of-flight mass spectrometry. The pharmacologically active α,β-unsaturated carbonyl group was the major metabolic site. The metabolic pathways included O-dealkylation, amide hydrolysis, dihydrodiol formation, hydroxylation, and secondary phase 2 conjugation. The metabolite of amide hydrolysis (M6) and 27,28-dihydrodiol allitinib (M10) were the major pharmacologically active metabolites in the circulation. The steady-state exposures to M6 and M10 were 11% and 70% of that of allitinib, respectively. The biotransformation of allitinib was determined using microsomes and recombinant metabolic enzymes. In vitro phenotyping studies demonstrated that multiple cytochrome P450 (P450) isoforms, mainly CYP3A4/5 and CYP1A2, were involved in the metabolism of allitinib. Thiol conjugates (M14 and M16) and dihydrodiol metabolites (M5 and M10) were detected in humans, implying the formation of reactive intermediates. The formation of a glutathione conjugate of allitinib was independent of NADPH and P450 isoforms, but was catalyzed by glutathione-S-transferase. P450 enzymes and epoxide hydrolase were involved in M10 formation. Overall, our study showed that allitinib was metabolized by the O-dealkylation pathway similar to lapatinib, but that amide hydrolysis and the formation of dihydrodiol were the dominant metabolic pathways. The absorbed allitinib was extensively metabolized by multiple enzymes.

Topics: Acrylamides; Antineoplastic Agents; Biotransformation; Caco-2 Cells; Chromatography, Liquid; Cytochrome P-450 Enzyme System; Epoxide Hydrolases; Feces; Female; Humans; Male; Mass Spectrometry; Microsomes, Liver; Neoplasms; Permeability; Quinazolines

AST1306 is an orally active irreversible small molecule inhibitor of EGFR (erbB1), HER2 (erbB2) and HER4 (erbB4) signaling. This is a phase I, open-label, dose-escalation study to evaluate the safety and tolerability, pharmacokinetics (PK), and preliminary anti-tumor effects of oral AST1306. In addition the effects of food on PK was tested.. A modified Fibonacci 3 plus 3 dose-escalation design was employed to determine the dose-limiting toxicity (DLT) and recommended phase II dose (RP2D) in patients with advanced solid tumors. The following dose levels were investigated: once daily (QD) at two dose levels (400-and 800 mg), twice daily (BID) in five dose levels (600-, 800-, 1000-, 1200- and 1500 mg), and three times daily (TID) in three dose levels (800-, 1000- and 1200 mg). In the PK and extension study, at least eight patients per dose cohort in three dose levels (maximum tolerated dose [MTD], one or two doses level lower than the MTD) were enrolled to evaluate the PK profiles.. Seventy-one patients were enrolled, with breast (n = 22) and lung cancers (n = 14) being the most common primary cancers. The most frequent drug-related adverse events were grade 1 to 3 diarrhea and rash, grade 1 to 2 fatigue. During dose escalation, the key DLT was grade 3 diarrhea observed in 5 patients at 1000 mg BID (n = 1), 1500 mg BID (n = 1), 800 mg TID (n = 1) and 1200 mg TID (n = 2). AST1306 was rapidly absorbed and had moderate to high clearance. PK concentration parameters increased with dose over the range evaluated, with no evidence of accumulation over time. Under fed conditions, the mean T(max) was prolonged, C(max) was increased, and AUC(0-∞) was raised. Of the 55 evaluable patients, 7 patients experienced partial responses, including 5 with breast cancer, 1 with lung cancer, and 1 with gastric cancer. The best response with stable disease for ≥ 6 months was achieved in 7 patients.. Based on the DLT and PK profile, the RP2D was defined as 1000 mg TID with evidence of preliminary anti-tumor activity. Further studies are recommended.

Topics: Acrylamides; Adolescent; Adult; Aged; Dose-Response Relationship, Drug; ErbB Receptors; Female; Humans; Male; Middle Aged; Neoplasms; Protein Kinase Inhibitors; Quinazolines; Receptor, ErbB-2; Treatment Outcome; Young Adult

The epidermal growth factor receptor (EGFR) is a member of the HER family of growth factors that activates several intracellular signaling pathways promoting proliferation and survival. EGFR over-expression is frequently associated with gene mutation or amplification, thereby constituting a major target for molecular therapies. Recently, a new generation of EGFR inhibitors has been developed with pan-HER properties and irreversible actions. Allitinib® (AST1306) is an orally active, highly selective irreversible inhibitor of the HER family of receptor tyrosine kinases with promising efficacies. In the present study we aimed to investigate the cytotoxicity of allitinib in a large panel of human cancer-derived cell lines and to correlate its efficacy to the mutational status of the EGFR, KRAS, BRAF, PI3KCA and PTEN genes. In addition, we aimed to evaluate the functional role of KRAS mutations in the response to this new inhibitor.. In total 76 different cancer-derived cell lines, representing 11 distinct histological types, were analyzed and classified into three groups: highly sensitive (HS), moderately sensitive (MS) and resistant (R). We found that 28 (36.8 %) cancer-derived cell lines exhibited a HS phenotype, 19 (25.0 %) a MS phenotype and 29 (38.1 %) a R phenotype. Allitinib showed a stronger cytotoxicity in head and neck, esophageal, melanoma and lung cancer-derived cell lines. We found that KRAS mutations were significantly associated with the R phenotype. To substantiate these results, an allitinib-sensitive lung cancer-derived cell line (H292) was transfected with plasmids carrying the two most common activating KRAS mutations (p.G12D and p.G12S). We found that both mutations reverted the allitinib-sensitive phenotype in these cells.. The current study represents the largest in vitro assessment of allitinib cytotoxicity performed to date. Through this study, we identified cancer types that could potentially benefit from this drug. Additionally, our findings suggest that prevalent KRAS mutations constitute potential predictive biomarkers for allitinib response.

Topics: Acrylamides; Cell Line, Tumor; Cell Survival; DNA Mutational Analysis; Drug Screening Assays, Antitumor; ErbB Receptors; Humans; Mutation; Neoplasms; Proto-Oncogene Proteins p21(ras); Quinazolines