Scientist Snapshot | Stephanie Johnson, Principal Process Development Scientist

Principal Process Development Scientist, Steph Johnson, joined our Deeside, Wales facility in 2011 after graduating with a PhD from Bangor University. In her current role, Steph is responsible for supporting the process development of GMP projects at the site.

Can you briefly describe your background and current role at Sterling?

After receiving my PhD from Bangor University, where I focused on utilising enzymes in the synthesis of non-natural amino acids. I moved into industry and joined what is now Sterling’s Deeside, Wales facility in 2011, which at the time was a small company specialising in antibody drug conjugate (ADC) process development, before Sterling acquired the facility in 2021.

While I gained an understanding of ADCs during my PhD, it wasn’t until I worked in an ADC lab that I really understood their complexity and started to master the process and analytical skills required to make them for customers. More than ten years on, and having made thousands of ADCs, I am still excited by this therapeutic modality.

The main focus of my role is working on GMP projects at the facility. I act as a technical lead on projects managing the process development activities and supporting the transfer of processes from development into the manufacturing facility.

Why have ADCs gained momentum in the last decade?

ADCs are desirable because of their ability to target cancerous cells directly, avoiding harm to healthy cells associated with treatments like chemotherapy. As I mentioned, commercially approved ADCs were relatively new when I began my career. with many more in various stages of clinical trials. Their advantages are clear, and researchers have even begun exploring their viability for treating indications aside from cancer.

It took some time for ADCs to gain momentum because they are quite complex, requiring careful selection of several components. Developing an ADC that is both safe and effective requires specialised expertise, with extensive knowledge of different linkers, conjugation chemistries, and more.

How does Sterling support customers’ ADC projects?

We provide extensive services in ADC discovery, development and manufacturing to assist customers with their ADC project. Our goal is always to help customers develop and manufacture a tailored ADC that meets their unique objectives. This includes proof of concept materials, process and analytical development, and production of larger batches for preclinical safety studies. Our team works very collaboratively to accomplish our customers’ goals, with everyone providing a unique contribution to each project.

Our work is supported by our ADC analytical team members, who are experienced in providing analytical services specifically for bioconjugation projects. Our facilities also provide the containment needed to work with a variety of potentially hazardous toxins that can be used in ADCs.

One of our greatest successes has been working on an ADC that was ultimately approved for commercial sale in the US. We have worked with this customer on a variety of projects for many years, and we were thrilled to help see this one through to commercial approval.

Our team supported this project in a number of ways over the course of its lifecycle, and we worked closely with the customer’s team every step of the way. This included performing extensive research and development work in its early stages, developing a scalable process, aiding in technology transfer, performing full process characterisation as the product went through clinical trials, and providing support in writing certain sections of the Biologics License Application (BLA) as the customer sought approval. As this customer continues to push more molecules forward, we continue to work collaboratively with them in their projects’ early phases as well as late stage process characterisation to help maximise their long-term success.

Why should customers choose to work with Sterling for ADC projects?

I think that our team’s broad range of experience in the ADC space is what really sets us apart. We’ve worked with a variety of customers on an extremely diverse range of projects, which has given us invaluable experience utilising different linker chemistries, antibody formats, toxins and drugs. As a result of this expertise, our customers recognise us for our commitment to getting things right first time, and our ability to satisfy even the most complex of requirements.

Beyond that, the reasons customers choose to work with Sterling on any project hold true for ADCs as well. We are committed to serving as true partners to our customers, and we work closely with them to meet their specific needs, overcome challenges, maintain outstanding quality and adhere to deadlines. We value building lasting customer relationships that are rooted in transparency and collaboration.

What do you enjoy most about working at Sterling?

The work we do is very varied, no two days are the same which keeps it exciting. The people at the site are also great to work with, and we have a very collaborative approach to our work.