From Whole Well to Single Cell: Enhancing Biosimilar Development 

By 2023, patents on nearly 20 oncology biologics will expire. This will open the door to more competition as off-brand biosimilars can enter the marketplace. We spoke to one of our assay development experts about the increasing pressure facing biosimilar drug developers and how advanced flow cytometry is addressing the need for robust comparability assays that are compatible with high-throughput formats.

^{This article is posted on our Science Snippets Blog} 

Biosimilars are large, complex biological therapies that closely relate to existing reference biologic drugs in terms of structure, function, purity, and potency. For example, Amjevita (Amgen) is the biosimilar of Humira (Abbvie), the original FDA-approved biologic for treating arthritic pain.  

Globally, pharmaceutical companies are moving hundreds of biosimilars through the drug development pipeline. Their critical needs are centered around high throughput platforms and reliable assays that enhance the biosimilar manufacturing process. 
In this interview, we spoke with Dr. Ben Tyrrell, one of our own Product Development Scientists, who develops assays as a service for Sartorius clients. He explains how the latest advances in flow cytometry technology are enabling biosimilar characterization at the single-cell resolution.

Why are biosimilars so important in cancer drug discovery?

On top of the constant pressure to reduce manufacturing costs, other trends include an increasing uptake of continuous manufacturing processes and the need for rapid feedback. Analytical workhorses remain MS-based analysis, advanced chromatography techniques or ELISAs, but over the last decade label-free biosensors are getting more popular, since they offer improved robustness, assay flexibility and throughput.  
 

What challenges still exist in developing biosimilars?

“With biosimilars, even small structural changes matter, so it’s important to carefully evaluate biosimilar activity in comparison to the reference drug using a wide range of orthogonal methods. Also, some monoclonal antibodies, such as those for immuno-oncology, require more complex assays.

While flow cytometry provides a greater level of data resolution compared to sample-averaging plate-based assays, the technology has been limited by low sample throughput and difficulties in translating workflows from adherent to suspension cell formats.”
 

How is your work helping to address these challenges?

“We’re developing flow cytometry-based binding assays for comparative studies of biosimilars. 

The first assay we transitioned from the traditional plate reader format to flow cytometry was a VEGF binding assay for Avastin biosimilars. An important benefit of flow cytometry was the ability to use live cells, which is a much more biologically relevant way of modeling surface receptor activity.

Using the iQue^® Advanced Flow Cytometry platform we developed and validated a robust live-cell binding assay that is compatible with challenging cell lines and a high throughput platform method.” 
 

The iQue^® allowed for physiologically-relevant assays and high-throughput formats. Another critical aspect is sample volume. We could run assays with only a few microliters.

How did the iQue^® platform facilitate this work?

“The iQue^® allowed for physiologically-relevant assays and high-throughput formats. Another critical aspect is sample volume. We could run assays with only a few microliters, which gave us more flexibility for assay optimization. It also meant we were working with batches of cells rather than successive passages.”

What projects will you be taking on next?

“My work is going to involve developing more complex assays on the iQue^® platform. In fact, since the VEGF live-cell binding assay platform, we have successfully developed complex platform bioassays for antibody-dependent cellular phagocytosis (ADCP), mixed lymphocyte reactions, and T-cell exhaustion. Some of the assays use Sartorius kits on the iQue^®, making the workflow much easier. 

Our goal is to simplify biosimilar development, so we’re looking forward to continuing collaborations with clients and seeing our work directly impact cancer therapeutic regimens.”