Quantification of surrogate monoclonal antibodies in mouse serum using LC-MS/MS.

Surrogate monoclonal antibodies (mAbs) used in preclinical studies can be challenging to quantify due to lack of suitable immunoaffinity reagents or unavailability of the mAb protein sequence. Generic immunoaffinity reagents were evaluated to develop sensitive LC-MS/MS assays. Peptides of unknown sequence can be used for selective LC-MS quantification.

A peptide immunoaffinity LC-MS/MS strategy for quantifying the GPCR protein, S1PR1 in human colon biopsies.

S1PR1, a G protein-coupled receptor (GPCR) protein, is a therapeutic target for treatment of autoimmune diseases. As a potential biomarker for drug effect and patient stratification, it is of great significance to measure it in biological samples. However, due to the hydrophobic nature of S1PR1 and the difficulties in extraction and solubilization, as well as low expression levels, quantitative determination of S1PR1 remains challenging.

Immunoaffinity microflow liquid chromatography/tandem mass spectrometry for the quantitation of PD1 and PD-L1 in human tumor tissues.

Rationale: High tumor expression of programmed cell death protein (PD1) and programmed death-ligand 1 (PD-L1) is thought to be associated with positive clinical outcomes after treatment with anti-PD1 or anti-PD-L1 agents. Several sensitive methods based on immunohistochemistry, ligand binding assay (LBA), and liquid chromatography/mass spectrometry involving the measurement of PD1 and PD-L1 expression have been reported. Here, we expand on the characterization of different tumor types using a highly specific, sensitive, and robust immunoaffinity liquid chromatography/tandem mass spectrometry (IA-LC/MS/MS)-based method for the simultaneous quantitation of PD1 and PD-L1 in tumor tissues.

LC/MS/MS-based quantitation of pig and human S100A1 protein in cardiac tissues: Application to gene therapy.

The S100A1 protein is a target of interest for the treatment of heart failure as it has been previously reported to be depleted in failing cardiomyocytes. A gene therapy approach leading to increased expression levels of the protein directly in the heart could potentially lead to restoration of contractile function and improve overall cell survival. S100A1 is a relatively small soluble protein that is extremely well conserved across species with only a single amino acid difference between the sequences in human and pig, a commonly used pre-clinical model for evaluation of efficacy, biodistribution and safety for cardiac-directed gene therapy approaches.

Identification of a Potent, Selective, and Efficacious Phosphatidylinositol 3-Kinase δ (PI3Kδ) Inhibitor for the Treatment of Immunological Disorders.

PI3Kδ plays an important role controlling immune cell function and has therefore been identified as a potential target for the treatment of immunological disorders. This article highlights our work toward the identification of a potent, selective, and efficacious PI3Kδ inhibitor. Through careful SAR, the successful replacement of a polar pyrazole group by a simple chloro or trifluoromethyl group led to improved Caco-2 permeability, reduced Caco-2 efflux, reduced hERG PC activity, and increased selectivity profile while maintaining potency in the CD69 hWB assay.

Discovery of Clinical Candidate 2-((2S,6S)-2-Phenyl-6-hydroxyadamantan-2-yl)-1-(3'-hydroxyazetidin-1-yl)ethanone [BMS-816336], an Orally Active Novel Selective 11β-Hydroxysteroid Dehydrogenase Type 1 Inhibitor.

BMS-816336 (6n-2), a hydroxy-substituted adamantyl acetamide, has been identified as a novel, potent inhibitor against human 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) enzyme (IC 3.0 nM) with >10000-fold selectivity over human 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2). 6n-2 exhibits a robust acute pharmacodynamic effect in cynomolgus monkeys (ED 0.

Quantification of in vivo site-specific Asp isomerization and Asn deamidation of mAbs in animal serum using IP-LC-MS.

Background: Isomerization of aspartic acid and deamidation of asparagine are two common amino acid modifications that are of particular concern if located within the complementarity-determining region of therapeutic antibodies. Questions arise as to the extent of modification occurring in circulation due to potential exposure of the therapeutic antibody to different pH regimes.

Results: To enable evaluation of site-specific isomerization and deamidation of human mAbs in vivo, immunoprecipitation (IP) has been combined with LC-MS providing selective enrichment, separation and detection of naive and modified forms of tryptic peptides comprising complementarity-determining region sequences.

Discovery of a Highly Selective JAK2 Inhibitor, BMS-911543, for the Treatment of Myeloproliferative Neoplasms.

JAK2 kinase inhibitors are a promising new class of agents for the treatment of myeloproliferative neoplasms and have potential for the treatment of other diseases possessing a deregulated JAK2-STAT pathway. X-ray structure and ADME guided refinement of C-4 heterocycles to address metabolic liability present in dialkylthiazole 1 led to the discovery of a clinical candidate, BMS-911543 (11), with excellent kinome selectivity, in vivo PD activity, and safety profile.

Quantification of human mAbs in mouse tissues using generic affinity enrichment procedures and LC-MS detection.

Background: The disease state can modulate the penetration of large antibody-sized therapeutic molecules into affected tissues. Suitable bioanalytical methods are required for the quantitative analysis of drug tissue levels to enable a better understanding of the parameters influencing drug penetration and target engagement.

Results: Described is a sensitive and selective LC-MS/MS assay for the quantification of human mAb molecules in mouse tissues.

Synthesis and structure-activity relationship of 2-adamantylmethyl tetrazoles as potent and selective inhibitors of human 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1).

A series of 2-adamantylmethyl tetrazoles bearing a quaternary carbon at the 2-position of the adamantane ring (i.e. structure A) have been designed and synthesized as novel, potent, and selective inhibitors of human 11β-HSD1 enzyme.

Quantitation of therapeutic proteins following direct trypsin digestion of dried blood spot samples and detection by LC-MS-based bioanalytical methods in drug discovery.

Background: There is considerable interest in the pharmaceutical industry today in both development of therapeutic proteins as viable biopharmaceutical agents as well as the implementation of microsampling techniques, such as dried blood spots (DBS), as an alternative to current sample collection and handling procedures for biological samples generated in drug discovery and development studies. We have demonstrated that these two techniques can be integrated by developing bioanalytical methods that simultaneously determine the concentrations of unique therapeutic protein constructs, using LC-MS-based detection of multiple surrogate peptides following direct trypsin digestion of DBS.

Results: Bioanalytical methods were developed for the simultaneous determination of two structurally different therapeutic proteins (PEGylated-Adnectin™-1, MW 11,144 amu and an Fc-fusion protein, MW 67,082 amu) in a single DBS sample using LC-MS-based detection of multiple peptides generated from different regions of the proteins following trypsin digestion.

Pellet digestion: a simple and efficient sample preparation technique for LC-MS/MS quantification of large therapeutic proteins in plasma.

Background: There is a need for a simple and efficient sample preparation technique for LC-MS/MS quantification of large therapeutic proteins in plasma.

Results: The sample preparation technique presented here is based upon trypsin digestion of the pellet obtained following precipitation of the protein analyte from plasma. The pellet digestion technique was shown to facilitate efficient digestion of large therapeutic proteins, with concomitant removal of a substantial amount of potentially problematic plasma phospholipids.

Discovery of 3-hydroxy-4-cyano-isoquinolines as novel, potent, and selective inhibitors of human 11β-hydroxydehydrogenase 1 (11β-HSD1).

Derived from the HTS hit 1, a series of hydroxyisoquinolines was discovered as potent and selective 11β-HSD1 inhibitors with good cross species activity. Optimization of substituents at the 1 and 4 positions of the isoquinoline group in addition to the core modifications, with a special focus on enhancing metabolic stability and aqueous solubility, resulted in the identification of several compounds as potent advanced leads.

Design, synthesis, and SAR studies of novel polycyclic acids as potent and selective inhibitors of human 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD-1).

Starting from high throughput screening hit 2-adamantyl acetic acid 3, a series of polycyclic acids have been designed and synthesized as novel, potent, and selective inhibitors of human 11β-HSD-1. Structure-activity relationships of two different regions of the chemotype (polycyclic ring and substituents on quaternary carbon) are discussed.

Development of a canine model to enable the preclinical assessment of pH-dependent absorption of test compounds.

A preclinical canine model capable of predicting a compound's potential for pH-dependent absorption in humans was developed. This involved the surgical insertion of a gastrostomy feeding tube into the stomach of a beagle dog. The tube was sutured in position to allow frequent withdrawal of gastric fluid for pH measurement.

Preclinical pharmacokinetics and in vitro metabolism of BMS-690514, a potent inhibitor of EGFR and VEGFR2.

BMS-690514, a potent inhibitor of human epidermal growth factor receptor (HER) 1 (EGFR), 2, and 4, and vascular endothelial growth factor receptors (VEGFR) 1-3, is currently under investigation as an oral agent for the treatment of solid tumors. In vitro and in vivo studies were conducted to characterize the pharmacokinetics and metabolism. Through integration of in vitro and in vivo pharmacokinetic data and antitumor efficacy in nude mice, human pharmacokinetics and efficacious doses were projected for BMS-690514.

Prediction of in vivo enantiomeric compositions by modeling in vitro metabolic profiles.

Identification and quantitation of drug metabolites are important for understanding and predicting drug-drug interactions and toxicities. For chiral compounds, metabolic interconversion of enantiomers may present unique challenges. If the stereoisomers are biologically distinguishable, regulatory agencies consider them distinct chemical entities and require individual characterization since enantiomers may exhibit different pharmacokinetic, pharmacologic, and toxicologic properties.

5-((4-Aminopiperidin-1-yl)methyl)pyrrolotriazine dual inhibitors of EGFR and HER2 protein tyrosine kinases.

Pyrrolotriazine dual EGFR/HER2 kinase inhibitors with a 5-((4-aminopiperidin-1-yl)methyl) solubilizing group were found to be superior to analogs with previously reported C-5 solubilizing groups. New synthetic methodology was developed for the parallel synthesis of C-4 analogs with the new solubilizing group. Interesting new leads were evaluated in tumor xenograft models and the C-4 aminofluorobenzylindazole, 1c, was found to exhibit the best antitumor activity.

Discovery of (S)-2-((S)-2-(3,5-difluorophenyl)-2-hydroxyacetamido)-N-((S,Z)-3-methyl-4-oxo-4,5-dihydro-3H-benzo[d][1,2]diazepin-5-yl)propanamide (BMS-433796): a gamma-secretase inhibitor with Abeta lowering activity in a transgenic mouse model of Alzheimer's disease.

We report on the design of benzodiazepinones as peptidomimetics at the carboxy terminus of hydroxyamides. Structure-activity relationships of diazepinones were investigated and orally active gamma-secretase inhibitors were synthesized. Active metabolites contributing to Abeta reduction were identified by analysis of plasma samples from Tg2576 mice.