Improving Multispecific Antibody Bioprocesses Through Co-Culture and
Column-Based Redox Reactions: Part II
Abstract
Multispecifics are increasingly being evaluated in the pharmaceutical
industry due to the unique mechanisms of action of the molecules, which
is enabled by the multiple antigen binding capability. The complexity of
these molecules can make production difficult, therefore different
approaches for the generation of these molecules have been developed.
The approach employed in this study utilizes electrostatic-steering,
wherein charge-based differences between two parental homodimer
antibodies are used to drive correct heterodimerization during a redox
reaction of the partially purified parental homodimers. This strategy
results in high conversion to the heterodimer with minimal
product-related impurities; however, this method also requires separate
bioreactors for each parental homodimer, resulting in complex
manufacturing campaigns. This work describes a new bioprocess for
electrostatic steering-based multispecifics. This strategy couples two
unique components. First, the two separate cell lines are co-cultured,
resulting in simultaneous production of both parental homodimers in a
single bioreactor. The second component utilizes a column-based redox
reaction, wherein the homodimers are captured and the disulfide bonds
reduced while bound to the protein A resin using a reductant wash. The
column is then eluted and neutralized to allow the reduced parental
homodimers to heterodimerize and finally, the addition of an oxidant
enables the disulfide bond reformation to complete the formation of the
multispecific. This new process is robust and efficient across bench and
manufacturing scales, with well-controlled impurity profiles. Through
this strategy, the new multispecific bioprocess is more similar to a
typical antibody-like bioprocess, enabling more efficient use of
clinical and commercial manufacturing resources, while resulting in the
production of complex multispecific molecules with minimal
product-related impurities.