Narine Baririan, Clinical pharmacology and PK expert at SGS has authored a technical paper on monoclonal antibody drugs looking at their pharmacological specificity
Several monoclonal antibody (mAbs) drugs have been approved, or are at the late stage of clinical development within various therapeutic indications.
The amount of mAbs making it to the market will continue to increase thanks to their characteristics, including good solubility and stability, long persistence in the body, high selectivity and specificity of action, and low risk of toxic metabolites.
However, mAbs still have complex pharmacokinetic (PK) and pharmacodynamic (PD) properties compared to small chemical molecules. These include poor bioavailability, slow distribution, both linear and non linear elimination processes, and other factors influencing PK and PD such as immune reactions/immunogenicity.
Analyses of a new compound’s PK and PD properties is an essential step in the early phases of drug development, and this process is still more complicated for mAbs.
Before planning a first-in-human (FIH) study, robust pre-clinical data should be available providing sufficient insight into the full PD pathways, and used to select the most appropriate animal species from both PK/PD and safety considerations.
Challenging steps in designing FIH with mAb drugs therefore remain, and include the selection of safe and appropriate starting dose; the choice of dose escalation steps to achieve the goal of FIH study; the planning of sufficient and correct followup procedures; and the safety monitoring necessary, considering both the short term infusion related reactions and delayed PD effects.
Due to incidents in the past, authorities look more rigorously towards mAbs, considering many of them as high-risk medicinal products. A sound early clinical development plan, including appropriate justifications, might help regulatory bodies with their evaluation of what they view as high-risk.