Accelerated Cell Culture Process Development for a Bispecific Antibody Program

Accelerated timelines can create significant challenges for antibody cell culture process development, particularly when cell line stability data are not yet available while downstream manufacturing milestones are already approaching.

In this project, the cell culture process development team needed to support the delivery of a 200L toxicology batch within just three months of the Cell Line Development (CLD) team initiating clone stability evaluation. To reduce the risk associated with waiting for final clone stability results, Protheragen initiated process development using minipools and subsequently optimized the process with the top five candidate clones.

By combining early process development, data-driven clone selection, staged technology transfer, and scale-up verification, the team successfully locked the cell culture process and completed the 200 L toxicology batch production on schedule.

The Challenge

The key challenge was the extremely limited time available between the initiation of clone stability evaluation and the planned delivery of the 200 L toxicology batch.

Only approximately three months remained from the start of clone stability assessment by the CLD team to the required delivery of the 200 L toxicology batch drug substance.

At this stage, the final production clone had not yet been fully confirmed based on the complete stability dataset. Waiting for the final stability results before initiating process development could therefore create a substantial risk of project delay.

The solution therefore required early process development combined with risk-managed clone selection and staged technology transfer.

Our Strategy

To avoid waiting for the final clone stability results, the Cell Culture Process Development (CCPD) team initiated process development using minipools.

Two rounds of process development were conducted at the minipool stage to establish and refine suitable culture conditions before the final production clone was confirmed.

This early-stage work generated process knowledge that could subsequently be applied to selected monoclonal clones, helping shorten the time required for final process optimization.

After the initial minipool development rounds, five leading clones were selected for process optimization.

Rather than relying on a single presumed final clone while stability evaluation was still ongoing, the process development team evaluated the top five candidates under the developing culture process.

This strategy reduced the risk associated with uncertainty in the final clone selection. If the stability assessment subsequently ruled out a candidate clone, process development information from the remaining candidates could still support rapid progression without restarting the entire process development program.

The final clone selection was supported by PDL30 pre-stability evaluation data, together with experience from previous development programs.

The candidate clones were assessed using multiple development considerations, including:

Based on the integrated assessment, the most suitable clone was selected to support final process locking.

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Fig. 1. Integrated workflow for minipool-based process development, candidate clone optimization, final clone selection, and subsequent process scale-up.

After process optimization and clone selection, the process was locked at the 10 L scale.

To maintain project continuity, technology transfer was conducted in stages, allowing the locked 10 L process to transition directly into preparation for the 200 L production campaign.

This staged transfer strategy enabled process knowledge and operating conditions established during development to be carried forward into the larger-scale production run, minimizing unnecessary gaps between process development and manufacturing.

Results

The integrated development strategy enabled the project to progress from early minipool process development to final clone selection, 10 L process locking, and 200 L production within the required timeline.

The 200 L scale-up results were highly consistent with the small-scale process performance, supporting the robustness of the developed cell culture process.

The toxicology batch was successfully manufactured and delivered on schedule, achieving:

These results demonstrated that the process established during development could be effectively transferred to the 200 L scale while maintaining the targeted productivity and product purity.

Key Outcomes

On-time Toxicology Batch Delivery

The 200 L toxicology batch was successfully produced and delivered according to the required project timeline.

Consistent Scale-up Performance

The 200 L production results were highly consistent with the performance observed during small-scale process development.

High Titer and Purity

The 200 L production campaign achieved a titer of >4.5 g/L with product purity of >95%.

Project Outcome

The project successfully demonstrated an accelerated and risk-managed approach to antibody cell culture process development under a highly compressed timeline.

By initiating development with minipools, optimizing the process across the top five candidate clones, and integrating PDL30 pre-stability data into final clone selection, the team was able to lock the 10 L process without waiting for the complete stability evaluation to conclude.

The staged technology transfer then enabled a smooth transition toward the 200 L manufacturing campaign. The 200L toxicology batch was delivered on schedule, with production performance highly consistent with small-scale development and final results exceeding 4.5 g/L in titer and 95% in purity.