Alteration of Physicochemical Properties for Antibody-Drug Conjugates and Their Impact on Stability

Abstract

a b s t r a c tAntibody conjugates, in particular antibody-drug conjugates (ADCs), are a fast-growing area in research and in the pharmaceutical industry. The covalent attachment of an antibody to a chemical moiety can be an effective measure for drug targeting or can also positively impact pharmacokinetics of small molecular compounds by serum half-life extension. Stability, physicochemical properties, and degradation pathways of biotherapeutics or small molecule therapeutics are often not totally known and understood. However, ADCs represent a hybrid of small molecular and macromolecular components, and their properties are still not fully understood and described. This review discusses the alteration of the physicochemical properties of antibodies upon conjugation of chemical moieties to its surface and the resulting impact on ADC stability.

Single chain variable fragment fused to maltose binding protein: a modular nanocarrier platform for the targeted delivery of antitumorals

“…brentuximab vedotin). However, this straightforward approach results in a random linkage of the drug to the antibody and yields heterogeneous mixtures with different drug-to-antibodies-ratios that impact the physicochemical properties, pharmacokinetics, and lot-to-lot reproducibility 42 . At the cost of increasing the complexity, the next generation of antibody-drug conjugates rely on sitespecific bioconjugation strategies such as THIOMABs technology, transglutaminase-mediated conjugations, click chemistry conjugation, bridge cysteine conjugations, glycosyl remodeling, to reduce the problems associated with heterogeneity and to enable antibody-like fragments to improve tumor penetration.…”

“…The increase in the drug-antibody ratio has been a classical approach not exempt from drawbacks, since it often affects pharmacokinetics and the increase of hydrophobicity is frequently one of the key factors to be considered. 42,56 To approach this challenge and inspired by a previous work that demonstrated the feasibility of using a nanobody-cyclodextrin conjugate as a site-directed drug delivery system 37 , we envisioned a modular design where the targeting module bears the MBP and the carrier module is maltosylated. As a proof of concept, PEI was functionalized with maltose and with β-cyclodextrin to obtain a multivalent platform that exploits the ability of cyclodextrin to form inclusion complexes with hydrophobic molecules such as chemotherapeutic anticancer drugs 57 and this effect measured as cytotoxicity was dependent on the expression HER2+.…”

Advances and Limitations of Antibody Drug Conjugates for Cancer

“…Modification of payloads with various functional groups, such as amine and thiol groups, to optimize conjugation as well as the impact of DAR, hydrophobicity on ADC clearance and improving conjugation methods to attain a homogenous ADC population, has been the primary focus of research in the field [ 45 , 46 , 47 ]. A high DAR and hydrophobicity entails the risk of immunogenic reactions and rapid clearance rates (further discussed in Section 5 ).…”

“…However, there is a risk of immunogenic reactions or faster clearance rates in some cases because of a high DAR [ 46 , 69 ]. Moreover, most of the cytotoxic agents are hydrophobic and the incorporation of many molecules can lead to decreased physical stability, the addition of branched PEG chains, and can increase the hydrophilicity of the linker, which has subsequently proven to have superior effects in vivo [ 47 , 65 , 66 ].…”

“…There are certain features that are essential in a cytotoxic payload: high cytotoxicity, low immunogenic effect, stability during storage in preparation and in the circulation, permeability, solubility clearance, and amenability to modification. In terms of hydrophobicity, the formation of a hydrophobic metabolite post intercellular cleavage exerts better blood clearance and safety [ 47 ]. Extreme hydrophobicity of the cytotoxic agent can alter the biological properties of the antibody and can consequently cause aggregation during storage or conjugation [ 47 ].…”