Absorption, Distribution, Metabolism, and Excretion of Capmatinib (INC280) in Healthy Male Volunteers and In Vitro Aldehyde Oxidase Phenotyping of the Major Metabolite.

Capmatinib (INC280), a highly selective and potent inhibitor of the MET receptor tyrosine kinase, has demonstrated clinically meaningful efficacy and a manageable safety profile in patients with advanced non-small-cell lung cancer harboring MET exon 14-skipping mutations. We investigated the absorption, distribution, metabolism, and excretion of capmatinib in six healthy male volunteers after a single peroral dose of 600 mg 14C-labeled capmatinib. The mass balance, blood and plasma radioactivity, and plasma capmatinib concentrations were determined along with metabolite profiles in plasma, urine, and feces. The metabolite structures were elucidated using mass spectrometry and comparing with reference compounds. The parent compound accounted for most of the radioactivity in plasma (42.9% ± 2.9%). The extent of oral absorption was estimated to be 49.6%; the Cmax of capmatinib in plasma was reached at 2 hours (median time to reach Cmax). The apparent mean elimination half-life of capmatinib in plasma was 7.84 hours. Apparent distribution volume of capmatinib during the terminal phase was moderate-to-high (geometric mean 473 l). Metabolic reactions involved lactam formation, hydroxylation, N-dealkylation, formation of a carboxylic acid, hydrogenation, N-oxygenation, glucuronidation, and combinations thereof. M16, the most abundant metabolite in plasma, urine, and feces was formed by lactam formation. Absorbed capmatinib was eliminated mainly by metabolism and subsequent biliary/fecal and renal excretion. Excretion of radioactivity was complete after 7 days. CYP phenotyping demonstrated that CYP3A was the major cytochrome P450 enzyme subfamily involved in hepatic microsomal metabolism, and in vitro studies in hepatic cytosol indicated that M16 formation was mainly catalyzed by aldehyde oxidase. SIGNIFICANCE STATEMENT: The absorption, distribution, metabolism, and excretion of capmatinib revealed that capmatinib had substantial systemic availability after oral administration. It was also extensively metabolized and largely distributed to the peripheral tissue. Mean elimination half-life was 7.84 hours. The most abundant metabolite, M16, was formed by imidazo-triazinone formation catalyzed by cytosolic aldehyde oxidase. Correlation analysis, specific inhibition, and recombinant enzymes phenotyping demonstrated that CYP3A is the major enzyme subfamily involved in the hepatic microsomal metabolism of [14C]capmatinib.

Continuous low-dose infusion of patupilone increases the therapeutic index in mouse and rat tumour models.

Patupilone is a microtubule-targeted cytotoxic agent with clinical efficacy, but causes diarrhoea in more than 80% of patients. The efficacy and tolerability of patupilone delivered continuously by subcutaneous (s.c.) mini-pumps [(mini-pump dose (MPD)] or by intravenous bolus administration [intravenous bolus dose (IVBD)] were compared preclinically to determine whether the therapeutic index could be improved. The antiproliferative potency in vitro of patupilone was determined by measuring total cell protein. Tumours were grown s.c. in rats (A15) or nude mice (KB31, KB8511) or intracranially in nude mice (NCI-H460-Luc). Efficacy was monitored by measuring tumour volumes, bioluminescence or survival. Toxicity was monitored by body weight and/or diarrhoea. Total drug levels in blood, plasma, tissues or dialysates were quantified ex-vivo by liquid chromatography-mass spectroscopy/mass spectroscopy. Patupilone was potent in vitro with GI50s of 0.24-0.28 nmol/l and GI90s of 0.46-1.64 nmol/l. In rats, a single IVBD of patupilone dose dependently inhibited the growth of A15 tumours, but also caused dose-dependent body weight loss and diarrhoea, whereas MPD achieved similar efficacy, but no toxicity. In mice, MPD showed efficacy similar to that of IVBD against KB31 and KB8511 tumours, but with reduced toxicity. In a mouse intracranial tumour model, IVBD was more efficacious than MPD, consistent with patupilone concentrations in the brain. MPD provided constant plasma levels, whereas IVBD had very high C0/Cmin ratios of 70-280 (rat) or 8000 (mouse) over the dosing cycle. Overall, the correlation of plasma and tumour levels with response indicated that a Cave of at least GI90 led to tumour stasis. Continuous low concentrations of patupilone by MPD increased the therapeutic index in s.c. rodent tumour models compared with IVBD by maintaining efficacy, but reducing toxicity.

Phenotypic and metabolic investigation of a CSF-1R kinase receptor inhibitor (BLZ945) and its pharmacologically active metabolite.

1. 4-[2((1R,2R)-2-Hydroxycyclohexylamino)-benzothiazol-6-yloxyl]-pyridine-2-carboxylic acid methylamide (BLZ945) is a small molecule inhibitor of CSF-1R kinase activity within osteoclasts designed to prevent skeletal related events in metastatic disease. Key metabolites were enzymatically and structurally characterized to understand the metabolic fate of BLZ945 and pharmacological implications. The relative intrinsic clearances for metabolites were derived from in vitro studies using human hepatocytes, microsomes and phenotyped with recombinant P450 enzymes. 2. Formation of a pharmacologically active metabolite (M9) was observed in human hepatocytes. The M9 metabolite is a structural isomer (diastereomer) of BLZ945 and is about 4-fold less potent. This isomer was enzymatically formed via P450 oxidation of the BLZ945 hydroxyl group, followed by aldo-keto reduction to the alcohol (M9). 3. Two reaction phenotyping approaches based on fractional clearances were applied to BLZ945 using hepatocytes and liver microsomes. The fraction metabolized (fm) or contribution ratio was determined for each metabolic reaction type (oxidation, glucuronidation or isomerization) as well as for each metabolite. The results quantitatively illustrate contribution ratios of the involved enzymes and pathways, e.g. the isomerization to metabolite M9 accounted for 24% intrinsic clearance in human hepatocytes. In summary, contribution ratios for the Phase I and Phase II pathways can be determined in hepatocytes.

Preclinical antitumor activity of the orally available heat shock protein 90 inhibitor NVP-BEP800.

Heat shock protein 90 (Hsp90) is a ubiquitously expressed molecular chaperone with ATPase activity involved in the conformational maturation and stability of key signaling molecules involved in cell proliferation, survival, and transformation. Through its ability to modulate multiple pathways involved in oncogenesis, Hsp90 has generated considerable interest as a therapeutic target. NVP-BEP800 is a novel, fully synthetic, orally bioavailable inhibitor that binds to the NH(2)-terminal ATP-binding pocket of Hsp90. NVP-BEP800 showed activity against a panel of human tumor cell lines and primary human xenografts in vitro at nanomolar concentrations. In A375 melanoma and BT-474 breast cancer cell lines, NVP-BEP800 induced client protein degradation (including ErbB2, B-Raf(V600E), Raf-1, and Akt) and Hsp70 induction. Oral administration of NVP-BEP800 was well tolerated and induced robust antitumor responses in tumor xenograft models, including regression in the BT-474 breast cancer model. In these tumor models, NVP-BEP800 modulated Hsp90 client proteins and downstream signaling pathways at doses causing antitumor activity. NVP-BEP800 showed in vivo activity in a variety of dosing regimens covering daily to weekly schedules, potentially providing a high degree of flexibility in dose and schedule within the clinical setting. Overall, given the mechanism of action, preclinical activity profile, tolerability, and pharmaceutical properties, NVP-BEP800 is an exciting new oral Hsp90 inhibitor warranting further development. Mol Cancer Ther; 9(4); 906-19. (c)2010 AACR.

Metabolism and disposition of imatinib mesylate in healthy volunteers.

Imatinib mesylate (GLEEVEC, GLIVEC, formerly STI571) has demonstrated unprecedented efficacy as first-line therapy for treatment for all phases of chronic myelogenous leukemia and metastatic and unresectable malignant gastrointestinal stromal tumors. Disposition and biotransformation of imatinib were studied in four male healthy volunteers after a single oral dose of 239 mg of (14)C-labeled imatinib mesylate. Biological fluids were analyzed for total radioactivity, imatinib, and its main metabolite CGP74588. Metabolite patterns were determined by radio-high-performance liquid chromatography with off-line microplate solid scintillation counting and characterized by liquid chromatography-mass spectrometry. Imatinib treatment was well tolerated without serious adverse events. Absorption was rapid (t(max) 1-2 h) and complete with imatinib as the major radioactive compound in plasma. Maximum plasma concentrations were 0.921 +/- 0.095 mug/ml (mean +/- S.D., n = 4) for imatinib and 0.115 +/- 0.026 mug/ml for the pharmacologically active N-desmethyl metabolite (CGP74588). Mean plasma terminal elimination half-lives were 13.5 +/- 0.9 h for imatinib, 20.6 +/- 1.7 h for CGP74588, and 57.3 +/- 12.5 h for (14)C radioactivity. Imatinib was predominantly cleared through oxidative metabolism. Approximately 65 and 9% of total systemic exposure [AUC(0-24 h) (area under the concentration time curve) of radioactivity] corresponded to imatinib and CGP74588, respectively. The remaining proportion corresponded mainly to oxidized derivatives of imatinib and CGP74588. Imatinib and its metabolites were excreted predominantly via the biliary-fecal route. Excretion of radioactivity was slow with a mean radiocarbon recovery of 80% within 7 days (67% in feces, 13% in urine). Approximately 28 and 13% of the dose in the excreta corresponded to imatinib and CGP74588, respectively.