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How to Choose a CDMO for the Manufacturing of Your Viral Vectors

In 2022, the global viral vector market boasted a staggering value of USD 3.10 billion. But what's even more thrilling is the projection for the future - a dazzling compound annual growth rate of 11.5% from 2023 to 2030.

Viral vectors, those stealthy carriers of genetic material, have emerged as the linchpin in the realm of cell and gene therapies (CGT). These therapies, with their potential to revolutionize medicine, are the lifeblood of this booming sector.

In this electrifying context, choosing the right Contract Development and Manufacturing Organization (CDMO) for viral vector production takes center stage. It's the foundation upon which successful CGT production stands, and it's not a decision to be taken lightly as the stakes can be very high for your company.

In this article, we'll shed light on the crucial factors you should weigh when making this pivotal decision.

Understanding Viral Vector Manufacturing

Imagine a microscopic courier service that can deliver genetic instructions with pinpoint precision to the very heart of our cells. This is precisely the role that viral vectors play in gene therapy.

These vectors, ingeniously fashioned from viruses like adeno-associated viruses and lentiviruses, have been transformed into molecular delivery vehicles. Stripped of their disease-causing potential, they retain the remarkable ability to efficiently transport genetic cargo.

Adeno-associated virus (AAV), for instance, are adept at infiltrating a wide array of mammalian cells, making them a top choice for applications like gene therapy and vaccine development.

Meanwhile, lentiviral vectors can seamlessly integrate their genetic payload into the host cell's genome, ensuring long-term expression of the desired genes.

Now, the question is, who are the masterminds behind these marvels?

Who manufactures viral vectors?

Viral vectors are not born out of thin air but are crafted by specialized companies like CDMOs.

These manufacturers are armed with the knowledge and infrastructure to produce viral vectors on a grand scale, catering to diverse applications, from the precision art of gene therapy to the global endeavor of vaccine development.

Some of these companies employ advanced techniques, such as genetically modified organisms and cell cultures (like mammalian or insect cells), to propagate their viral vectors. Others harness the power of cutting-edge DNA engineering to craft vectors of unparalleled efficiency. This diversity of actors in the field fuels a competitive market, fostering innovation and propelling the boundaries of viral vector manufacturing.

Importance of Viral Vector Manufacturing

In the realm of gene therapy, viral vectors are the essential vehicles for delivering corrected genes into target cells. The efficient production of these gene therapies hinges on viral vector manufacturing, without which the dreams of genetic medicine would remain unfulfilled.

The role of viral vectors extends to the world of vaccines. Here, they are used to transport antigens and rouse the immune system, orchestrating a defense against infectious diseases. Effective viral vector manufacturing is the linchpin in ensuring the creation of safe and potent vaccines, safeguarding populations against a host of menacing diseases.

In essence, viral vector manufacturing is not just a cog in the biotechnological wheel; it is the driving force behind a new era of medical marvels. As we journey through this riveting landscape, let's explore how to choose the perfect partners in viral vector manufacturing, for they are the architects of the future.

What is the role of a CDMO?

What makes a good CDMO?

A good CDMO for viral vector manufacturing stands out by offering robust and reliable manufacturing processes. They have a track record of consistently delivering high-quality products, meeting timelines, and ensuring regulatory compliance.

For example, their facilities are equipped with state-of-the-art equipment and systems to support scalable production, maintaining stringent control over the manufacturing process.

Additionally, they have a knowledgeable and experienced team that understands the intricacies of viral vector manufacturing, enabling them to effectively troubleshoot any challenges that may arise. With a strong focus on quality and operational excellence, a good CDMO provides its clients with peace of mind and confidence in the manufacturing process.

What are the challenges of viral vector production?

Viral vector production faces several challenges.

Firstly, achieving high yields of viral vectors can be difficult due to limitations in manufacturing processes.

For example, the need for high cell density cultures increases the risk of contamination, reducing overall productivity.

Additionally, the purification of viral vectors can be complex and time-consuming. For instance, impurities such as host cell proteins and DNA fragments must be carefully removed to ensure the safety and efficacy of the final product.

Furthermore, scalability is a challenge in viral vector production. As demand for gene therapies grows, the ability to scale up production while maintaining consistent quality becomes crucial. Meeting these challenges is vital for the successful and efficient manufacturing of viral vectors.

5 Factors to Consider When Choosing a CDMO

Expertise in Viral Vector Manufacturing

When it comes to selecting a CDMO for viral vector production, the value of prior experience cannot be overstated.

Viral vector manufacturing is a highly specialized field with unique challenges and nuances. CDMOs with previous experience have honed their expertise in this domain. They possess an in-depth understanding of the intricacies, from selecting the most suitable viral vector platform to optimizing production processes. This expertise translates to a smoother, more efficient manufacturing process and a higher likelihood of success.

The world of biotechnology can be unpredictable, with unexpected challenges often arising during the manufacturing process. CDMOs with a history in viral vector production have encountered and overcome these challenges. They bring a problem-solving mindset, swiftly addressing issues and implementing effective solutions. This not only minimizes potential setbacks but also ensures that the project remains on track.

Learning from past projects, experienced CDMOs have streamlined their processes for maximum efficiency. This translates to reduced project timelines and cost savings, as they can anticipate and mitigate potential bottlenecks or inefficiencies.

Take for instance GenScript ProBio and its track record of successful projects:

“We supported a novel lentivirus-like particles project with no existing reference in the market. We tailored a unique potency analytical method for lentivirus-like particles and established a high-quality manufacturing process and quality control system. We managed the Common Technical Document (CTD) writing and led successful responses to FDA comments, ultimately securing Investigational New Drug (IND) approval in mid-2023.”, explains Sarah Li, Associate Director-PD/MSAT at GenScript ProBio.

She also adds: “In another instance with a customer based in the EU, aiming to develop TCR therapies for a wide range of cancers, we optimized the plasmid manufacturing process, significantly reducing turnaround time from 4 weeks to 2 weeks. Our collaboration resulted in one project obtaining FDA IND approval in early 2023 and successfully progressing to clinical trials.”

Ultimately, clients benefit from the peace of mind that comes with choosing a CDMO with a proven track record in viral vector manufacturing. Additional expertise in areas such as plasmid production can also improve efficiency and speed troubleshooting.

When choosing your CDMO, knowing that your partner has successfully delivered similar projects in the past is a key aspect to consider.

Quality Control and Regulatory Compliance

Quality control and regulatory compliance are vital components in the production of viral vectors. These processes ensure that the vectors meet the necessary standards and guidelines set by regulatory bodies.

For example, rigorous testing and analysis are conducted to confirm the purity, potency, and stability of the vectors.

As Sarah Li explains: “Each processing step shall be executed against validated, approved, and controlled standards and parameters and with quality assurance oversight. Processing shall also be performed in controlled clean room environments which are routinely monitored and tested. Quality controls shall be established with 100% traceability, spanning from incoming raw material inspection and testing, in-process testing of intermediates, and finished product testing for release, in order to ensure processing efficiency and overall product quality.”

Additionally, adherence to Good Manufacturing Practices (GMP) is crucial to ensure the consistent quality and safety of the products. Robust documentation and record-keeping play a significant role in regulatory compliance, providing transparency and traceability throughout the manufacturing process. By implementing these measures, manufacturers can confidently deliver reliable and compliant viral vectors for various applications.

In fact, an experienced CDMO will go one step further and put in place additional security measures. Here's what Sarah Li has to say:

“To enhance process robustness, we established critical process parameters(CPPs) through quality-by-design (QbD) methods, improving quality and consistency. We follow a standardized approach to process development, tech transfer, and scale-up, beginning with risk assessment and culminating in process validation. This meticulous approach ensures control and transparency throughout the entire production process.”

Finally, when it comes to regulatory compliance, the details matter a lot to Sarah Li and her team:

“All production processes, testing, and monitoring methods shall be fully validated. Furthermore, all processing activities shall be thoroughly documented, abiding by Good Documentation Practices. This shall guarantee visibility and traceability of all batch-related information for the customer. Moreover, our facilities, from the manufacturing floor to the quality control laboratories to the warehouse, are maintained in a constant audit-ready state to ensure good standing with governing regulatory bodies.”

Scalability and Capacity

Scalability and capacity are crucial considerations in viral vector manufacturing. The ability to scale up production quickly and efficiently is essential for meeting the growing demand for viral vectors in gene therapy and vaccine development.

For example, a manufacturing facility should have the capacity to produce large quantities of viral vectors to meet the needs of clinical trials or commercial production.

Additionally, scalable manufacturing processes can ensure consistent quality and reduce costs through economies of scale. By optimizing scalability and capacity, manufacturers can effectively meet the needs of the biopharmaceutical industry.

Once again, experience makes all the difference, as Sarah Li explains from her own practice:

“Working through the supply chain challenges of the COVID-19 pandemic, valuable lessons were learned with regard to business continuity. Our Business Continuity Plan (BCP) is a cornerstone of our organization’s overall risk management strategy, and our continuity team is dedicated to devising and managing this plan in the face of any supply chain disruption. One facet of this plan was built into the design of our facility: the maintenance of multiple fully qualified manufacturing lines. Another facet is the management of resource contingencies by fully qualifying primary, secondary, and tertiary raw material suppliers. Constant demand monitoring and forecasting in close collaboration with our commercial team has allowed for diversification to worldwide suppliers. However, the process by which these suppliers are qualified is strictly regulated within our quality system, thus ensuring consistent product quality for our customers.”

Another aspect to consider when choosing a CDMO is its physical location and distribution channel.

In the example of GenScript ProBio for instance, Sarah Li explains:

“Our location is strategically surrounded by numerous pharmaceutical companies, technology firms, and universities, providing access to a wealth of collaborations and opportunities and a pool of high-quality employees, ensuring we deliver top-notch services. GenScript ProBio’s proximity to Newark and JFK airports facilitates swift global product delivery. It is close to our GenScript site, offering gene synthesis and sequencing services, allowing us to provide a one-stop solution from conceptualization to commercial production.”

In addition, GenScript ProBio has invested in an upcoming U.S. GMP site in East Hanover, New Jersey, scheduled to open in August 2024. This state-of-the-art facility will specialize in GMP plasmid DNA and mRNA manufacturing, and underscores the company's efforts to continually expand its capabilities in key areas such as the U.S.

Technology and Innovation

To keep pace with the demands of this dynamic field, CDMOs must not only embrace but actively champion the most advanced technologies and innovations.

Cutting-edge technologies empower CDMOs to attain unprecedented levels of precision. From gene editing techniques to novel purification methods, these innovations ensure that the viral vectors produced are of the highest quality, meeting the stringent standards required for gene therapies.

Innovative technologies allow CDMOs to scale up production while maintaining consistent quality, bridging the gap between supply and demand. This is especially crucial in the context of gene therapies, where even a minor disruption in production can have a profound impact on patient well-being.

Innovation doesn't just translate to state-of-the-art equipment; it also means finding more efficient and cost-effective ways to achieve results. CDMOs that harness innovative approaches can offer competitive pricing while maintaining the highest quality standards.

Regulatory bodies constantly update and refine their guidelines. CDMOs that embrace innovative technologies can swiftly adapt to these changes, ensuring that the manufacturing process remains in strict compliance. This not only reduces the risk of regulatory setbacks but also provides clients with confidence in the quality and safety of the final product.

GenScript ProBio is one of those CDMOs that constantly invest in new technology. As Sarah Li explained: “Our new production site based in Zhenjiang is being built to meet current GMP requirements. Much time and resources have been invested to design a state-of-the-art manufacturing facility which will provide our customers with the highest standards in terms of product yield, product quality and consistency, and overall turn-around time to delivery.”

In a crowded marketplace, CDMOs that are at the forefront of innovation gain a significant competitive edge. They attract clients looking for partners who can not only meet their current needs but also anticipate future trends and requirements.

Collaboration and Communication

The role of a CDMO extends beyond the confines of the laboratory. One of the most critical facets of their responsibility lies in fostering effective and transparent communication with their clients.

The journey begins by thoroughly understanding the unique needs and aspirations of the client. This understanding serves as the bedrock upon which the entire manufacturing process is built.

With a clear understanding of the client's vision, a good CDMO becomes a problem solver and innovator. They tailor solutions that are not just technically sound but also aligned with the client's objectives. They provide a variety of options, explaining the pros and cons, so that the client can make informed decisions.

Throughout the manufacturing journey, clients are provided with real-time updates on the progress, ensuring that they are aware of any developments or challenges. This transparency fosters trust and allows for quick decision-making in case of unexpected hurdles.

In the event of issues or unexpected setbacks, the CDMO plays a critical role in troubleshooting and collaboratively finding solutions. Their experienced team should be ready to tackle challenges head-on, ensuring that the project stays on track.

The CDMO also communicates the stringent quality control measures and regulatory compliance protocols they follow. This ensures that the client understands the level of rigor involved in the manufacturing process and provides reassurance regarding the quality and safety of the final product.

Meeting deadlines is another aspect where communication is crucial. The CDMO should provide a clear timeline for project completion and keep the client informed of any changes or adjustments to the schedule.

In essence, the role of a CDMO in communication with the client is akin to that of a trusted guide, steering the project toward success.


Choosing a CDMO for the production of viral vectors involves careful consideration of the five key factors we’ve explored.

One must evaluate the CDMO's expertise in viral vector manufacturing, including their experience with different vector types and platforms. The scalability and reliability of the CDMO's manufacturing process are essential, as well as their ability to meet regulatory requirements.

It is crucial to assess their facility's capabilities, capacity, and track record in achieving high-quality and consistent yield.

Now that you’re armed with this knowledge, it’s time to reach out and find the best option for your drug development.

Related resource: Making Cell and Gene Therapy Manufacturing Accessible