Application of a High Throughput and Automated Workflow to Therapeutic Protein Formulation Development.

Rapid and efficient formulation development is critical to successfully bringing therapeutic protein drug products into a competitive market under increasingly aggressive timelines. Conventional application of high throughput techniques for formulation development have been limited to lower protein concentrations, which are not applicable to late stage development of high concentration therapeutics. In this work, we present a high throughput (HT) formulation workflow that enables screening at representative concentrations via integration of a micro-buffer exchange system with automated analytical instruments. The operational recommendations associated with the use of such HT systems as well as the efficiencies gained (reduction in hands-on time and run time by over 70% and 30%, respectively), which enable practical characterization of an expanded formulation design space, are discussed. To demonstrate that the workflow is fit for purpose, the formulation properties and stability profiles (SEC and CEX) from samples generated by the HT workflow were compared to those processed by ultrafiltration/diafiltration, and the results were shown to be in good agreement. This approach was further applied to two case studies, one focused on a formulation screen that studied the effects of pH and excipient on viscosity and stability, and the other focused on selection of an appropriate viscosity mimic solution for a protein product.

Evaluation of effects of Fc domain high-mannose glycan on antibody stability.

Elevated levels of CH2 domain N-linked high-mannose (HM) glycans are commonly observed in therapeutic monoclonal antibodies at various stages of the development. The effect of HM glycans on antibody stability was evaluated by using two approaches. In the first approach, immunoglobulin G (IgG) 1 material containing 21% HM was incubated at 29°C for 6 weeks and fractionated into monomeric and aggregate species by using size-exclusion chromatography (SEC). These fractions were analyzed for the levels of HM. No significant difference was observed in the amount of HM in aggregate and monomer fractions indicating that the HM-containing fractions did not have a greater tendency to form aggregates. In the second approach, both IgG1 material and IgG2 material were separated by Concanavalin-A affinity chromatography into a HM-enriched fraction and a HM-depleted fraction, respectively. Real-time and accelerated stability studies were carried out with these fractions together with untreated samples under standard formulation conditions. The stability of these fractions over time was monitored using SEC and cation-exchange chromatography. No significant difference was observed in rates of aggregation or charge variant formation. These data indicate that HM glycans had no effect on the IgG1 and IgG2 product's stability under the formulation conditions studied.

Contributions of a disulfide bond to the structure, stability, and dimerization of human IgG1 antibody CH3 domain.

Recombinant human monoclonal antibodies have become important protein-based therapeutics for the treatment of various diseases. The antibody structure is complex, consisting of beta-sheet rich domains stabilized by multiple disulfide bridges. The dimerization of the C(H)3 domain in the constant region of the heavy chain plays a pivotal role in the assembly of an antibody. This domain contains a single buried, highly conserved disulfide bond. This disulfide bond was not required for dimerization, since a recombinant human C(H)3 domain, even in the reduced state, existed as a dimer. Spectroscopic analyses showed that the secondary and tertiary structures of reduced and oxidized C(H)3 dimer were similar, but differences were observed. The reduced C(H)3 dimer was less stable than the oxidized form to denaturation by guanidinium chloride (GdmCl), pH, or heat. Equilibrium sedimentation revealed that the reduced dimer dissociated at lower GdmCl concentration than the oxidized form. This implies that the disulfide bond shifts the monomer-dimer equilibrium. Interestingly, the dimer-monomer dissociation transition occurred at lower GdmCl concentration than the unfolding transition. Thus, disulfide bond formation in the human C(H)3 domain is important for stability and dimerization. Here we show the importance of the role played by the disulfide bond and how it affects the stability and monomer-dimer equilibrium of the human C(H)3 domain. Hence, these results may have implications for the stability of the intact antibody.