Overcoming challenges associated with the bioanalysis of cysteine-conjugated metabolites in the presence of antibody-drug conjugates.

Investigations have shown that for the antibody-drug conjugate (ADC) belantamab mafodotin, concentrations of the cysteine-conjugated metabolite, Cys-mcMMAF, were overestimated in the presence of the ADC during sample processing when utilizing a historical SPE method. A new assay was developed utilizing an acidic protein precipitation to remove the ADC early in the extraction process, thus eliminating the risk of overestimating Cys-mcMMAF in the presence of belantamab mafodotin. experiments demonstrated a linear relationship between the concentration of belantamab mafodotin and the release of Cys-mcMMAF.

Modify on the fly: triple quad to high resolution in support of a dermal clinical study requiring an ultra low LLOQ.

Background: FTIH studies can be challenging due to the varying dosing regimens and rapid data delivery. Chemists are asked to provide ultra-low limits of quantitation to provide an understanding of patient efficacy and safety in order to progress drug development. In a recent dermal study it became necessary to reduce the LLOQ of a small molecule drug from 50 to 1 pg/ml due to reductions in the dose and surface area of drug application.

Application of DBS for quantitative assessment of the peptide Exendin-4; comparison of plasma and DBS method by UHPLC-MS/MS.

Background: An investigation was performed in order to establish if dried blood spots (DBS) could be applied to the quantitation of biopharmaceuticals in biological matrices and perform equivalently in terms of accuracy, precision and stability to traditional plasma methods.

Results: A method was successfully validated for the peptide Exendin-4 (39 amino acids in length) utilizing DBS technology. The validated DBS method resulted in a more sensitive and simplistic method than an existing monkey plasma method and required tenfold less sample volume.

Absolute quantification of a therapeutic domain antibody using ultra-performance liquid chromatography-mass spectrometry and immunoassay.

Background: Domain antibodies (dAbs; ∼10-15 kDa) are made up of the variable heavy chain or the variable light chain of the antibody structure, and retain binding capability. dAbs have proved difficult to detect in plasma using immunoassay without specific antibodies raised against the dAb.

Results: A sensitive and selective UPLC-MS/MS method for the absolute quantification of a dAb in monkey plasma was developed (range: 1 to 500 ng/ml) without the need for a specific capture antibody.