Optimization of Drug-Linker to Enable Long-term Storage of Antibody–Drug Conjugate for Subcutaneous Dosing

Abstract

To facilitate subcutaneous dosing, biotherapeutics need to exhibit properties that enable high-concentration formulation and long-term stability in the formulation buffer. For antibody–drug conjugates (ADCs), the introduction of drug-linkers can lead to increased hydrophobicity and higher levels of aggregation, which are both detrimental to the properties required for subcutaneous dosing. Herein we show how the physicochemical properties of ADCs could be controlled through the drug-linker chemistry in combination with prodrug chemistry of the payload, and how optimization of these combinations could afford ADCs with significantly improved solution stability. Key to achieving this optimization is the use of an accelerated stress test performed in a minimal formulation buffer.

Discovery of ABBV-154, an anti-TNF Glucocorticoid Receptor Modulator Immunology Antibody-Drug Conjugate (iADC)

“…As summarized in Table for DSF and DSC measurements, ADC11 has quite comparable conformational stability as ADC5 and ADC9 as well as other DAR4 ADCs in terms of unfolding temperatures and unfolding energy, suggesting similar impact on the domain stability by conjugation with DL10 versus maleimide linkers. As with ADC5 and ADC9 , ADC11 has unfolding temperatures ( T onset ) > 50 °C and aggregation onset temperature ( T agg ) > 65 °C, indicating a low probability of unfolding-driven aggregation at the typical temperatures under downstream CMC conditions.…”

“…To understand the impact of introducing BrAc as the conjugatable group on the physiochemical properties, ADC11 was subjected to our in-house characterization screening panel, which included conformational stability by differential scattering fluorimetry (DSF) and differential scanning calorimetry (DSC), apparent hydrophobicity by HIC, isoelectric point by icIEF, concentration behavior by iBEACON, viscosity and diffusion coefficient by Viscosizer, and the data are summarized in Tables and , respectively. Data on ADC5 and ADC9 generated in an earlier study are included here for comparison.…”

“…Equilibrium of Succinimide Ring-Closed (ADC7) and Open Hydrolyzed Form (ADC5) phosphate on the payload hydroxyl. 26 By hydrophobic chromatography retention time the DAR4 ADC was shown to have a hydrophobicity almost matching that of the parental antibody; however, the ADC was observed to form a gel. Since the PO 4 prodrug on the payload, and both the COOH groups of the glutamic acid and the ring opened succinimide all add negative charge to the ADC molecule, it is likely that this gelling phenomenon is due to the unfavorable electrostatic interactions between ADC molecules resulting from the large decrease of its isoelectric point.…”

“…Previous work has shown that hydrophobicity and isoelectric points are two key parameters that contribute to ADC stability. 26 Analytical hydrophobic interaction chromatography (HIC) using a mobile phase without any organic solvent was used to assess the apparent hydrophobicity of the ADCs relative to the parent mAb. Conjugation of the linker and payload typically resulted in ADCs having longer retention times compared to the parent mAb.…”

“…Introduction of the phosphate prodrug and the hydrophilic linker DL4 greatly reduced the apparent hydrophobicity with both human anti-TNF ADCs having retention times close to the parent antibody (Table 5). 26 However, it was observed that ADC9 gelled during storage at both 4 and 25 °C with this phenomenon being hypothesized to result from the extensive negative charge (eight COOH groups and four phosphates on the DAR4 ADC) that causes a large decrease in the isoelectric point and induces strong and unfavorable molecular interactions. While the overall properties for ADC9 were promising, the gelling phenomenon along with its high viscosity were considered likely to make the development of ADCs with this drug-linker challenging.…”