Methods for Determining the PK Parameters of AlbudAbs and of Long Serum Half-Life Drugs Made Using the AlbudAb Technology

Increasing serum residence time of drugs by means of fusing them to albumin-binding domain antibodies (AlbudAbs™) has previously been documented. AlbudAbs™ provide a valuable method for increasing the efficacy of drugs by extending the time for which therapeutic levels of drug are present in the body and also for increasing the convenience to the patient by reducing the need for frequent dosing. Here, we describe methods that could be used preclinically to determine the suitability of drug-AlbudAbs™ for development. Particular focus is given to suggested in vivo study design which could enable the fitting of accurate PK parameters, assay methods for concentration determination of AlbudAbs™ in blood samples, and to the protocols used to fit PK parameters to AlbudAb™ concentration data. Whilst the examples cited here are focussed on the AlbudAb™ technology, similar methods could be used for assessing the success of other half-life extension technologies (drug Fc fusions, PEGylated drugs).