With increasing evidence for microbial involvement in many human diseases, live biotherapeutic products (LBPs)—living microbes administered therapeutically—have emerged as a group of exciting new drug candidates. Although the LBP regulatory environment remains uncertain, companies all over the world are currently developing LBPs to address one or more diseases associated with an altered microbiota, from gastrointestinal infections and systemic inflammatory diseases to skin-related conditions.
After completing the complex and painstaking scientific research necessary to create a candidate LBP, a company must face the next challenge: addressing the practical aspects of manufacturing the product, which will enable clinical trials to be conducted.
Special expertise is required to establish the manufacturability of these ‘living drugs’. Indeed, the manufacturing of bacterial strains for therapeutic use differs from that of traditional drugs on many levels: manufacturing process development, scale-up, and even defining the drug’s critical quality attributes. For LBPs, no two manufacturing processes are alike—each one is designed around the specific strain or strains, with equipment and strategies being leveraged to achieve the objectives.
Fortunately, some success stories exist in the realm of LBP manufacturability development. Using a case study of an engineered bacterial strain being developed as a skin therapeutic, here is a brief checklist for companies ready to move into LBP manufacturing.
Partnering with a CDMO
LBP developer Azitra required a partner for developing the manufacturing process for its engineered live bacterial strain being developed as a skin therapeutic. The company chose to collaborate with the France-based CDMO Biose industrie, given the company’s 60-year history working with live bacteria and its capabilities in human microbiota-focused products.
The successful partnership began in 2018, focusing on a genetically modified S.epidermidis product. Richard Ellis, Director of Business Development at Biose industrie, says,
“Our initial role was to bring this modified microorganism called ATR-04 into the GMP manufacturing process, paying attention to the potency and the yield throughout the entire process. We also wanted to track the expression of specific molecules.”
Ellis believes the success of the project was attributable to at least seven factors addressed by the partners as they worked together:
1. Identify a realistic timeline.
Since the achievement of milestones tends to be highly important in the life of a start-up company or other LBP developer, Ellis advises careful consideration of timelines at the outset of the project. The timelines may depend on the clinical phase of the LBP or the investor requirements (for example, ‘proof of concept’).
“With our clients, we set up a timeline for development step-by-step, from safety evaluation to first steps in manufacturing, including scale-up processes and validation at each stage. Based on the results at each point, we come together to decide whether it’s ‘go’ or ‘no go’.”
Travis Whitfill, Azitra Co-founder and Executive Director of Advanced Technology, says,
“Biose industrie did a really good job of giving us a timeline and being able to stick to it. Given the inherent risk of drug development, this was a unique advantage to working with Biose industrie. This made it easy to report back to our investors, keeping promises and communicating clearly.”
Nevertheless, both parties agree it’s prudent to build in some flexibility. Who could have foreseen, after all, the global COVID-19 pandemic that paused clinical trials around the world? At present, Biose industrie reports that it is maintaining support for all client projects. Ellis says,
“Despite some of our clients temporarily suspending early stage clinical trials for certain indications, the work we are doing on most of our projects is continuing smoothly.”
2. Consider safety requirements first.
Each project starts with a safety assessment before anything occurs in the Biose industrie’s R&D or GMP production departments. Ellis says,
“To guarantee the safety of our projects, we get to know each strain in detail through genomic and microbiological data before introduction to our facilities. Only when every control was successfully validated, as was the case for Azitra’s strain, did we start developing the manufacturing process.”
Cleaning and disinfection procedures are a critical part of developing a GMP product that is deemed safe — and in the case of Azitra’s GMO product, even more scrutiny was required. Safety procedures were developed and implemented before the GMP steps. Ellis says the team, if required, finds the best strategy by doing a risk analysis, consulting collaborators, or learning from the successes of other ongoing projects.
3. Understand the logistics.
Whitfill says he felt Biose industrie was the right partner for the Azitra project even though, as an American company working with a European CDMO, geographical constraints might pose a challenge. But according to both parties, frequent communication and regular weekly meetings helped the project go smoothly.
And regarding possible shipment constraints? Ellis explains,
“Since there were multiple shipments to schedule, Biose industrie selected an experienced logistics agency that took care of shipment with a global network of known partners. This way, we were able to send the materials we produced under controlled temperatures anywhere in the world.”
4. Focus on potency at each step to prepare for regulatory scrutiny.
Since Biose industrie ensures support for clients in the regulatory aspects of each project, potency is a primary concern. Ellis says,
“The potency of the LBP strain is evaluated according to regulatory standards for each step, to ensure the quality of the collections and the drug product itself, and how the process can affect it.”
Moreover, with an engineered bacterial therapeutic, predictive assays of strain activity are crucial to establish potency. Biose industrie aimed to integrate, transfer, and adapt the best protocol for analysis.
Measuring potency for the Azitra LBP candidate was not straightforward, however. Whitfill says,
“Because our microbes are engineered, testing the potency of the product was more complex. It had to be measured in various ways—we had to define how much protein was produced by the product in addition to how many CFUs per gram were in the product.”
5. Find ways to achieve suitable stability, yield, and concentration for your needs.
Biose industrie closely examined strain metabolism in order to obtain high yield using high quality components dedicated for GMP production. For Azitra, the ATR-04 project resulted in a Master Cell Bank / Working Cell Bank and Drug Substance already stable for one year, with confidence of longer-term stability. They also successfully produced a drug substance at more than 1012CFU/g.
“The yield and the concentration process are both essential for the validation of a process, and our development approach was efficient in obtaining an optimized manufacturing process and a product of high quality according to GMP standards.”
6. Consider scalability of the manufacturing.
“Scalability was important to us: making sure we could set up the manufacturing process now for larger scale production in the future,” says Whitfill. “We appreciated working with a fully integrated CDMO that can do up to commercial scale production.”
According to Ellis,
“We generally operate by carrying out a development phase at low scale with qualified and controlled raw materials, according to GMP standards. We build from there.”
For the Azitra project, Biose industrie developed the drug formulation on a small scale in their R&D lab, then evaluated the manufacturing step by step, starting with few milliliters and progressing to 2-liter and 5-liter bioreactors and pilot scale confirmation at 20 liters. In the case of the Azitra product, the batch sizes were satisfied in a 150-liter bioreactor for final GMP manufacturing. Biose industrie currently has a 3500-liter-capacity bioreactor for the production of drug substances, and will soon acquire a 5000-liter capacity bioreactor.
7. Work with a great project manager.
All of the Project Managers at Biose industrie are microbiologists or bioprocessing engineers holding doctoral degrees, who thoroughly understand the complexities of bioprocess development and GMP manufacturing.
“Our great project managers arecrucial to client satisfaction—and it’s only because of their hard work and ingenuity that these drug products are able to advance through manufacturing to finally reach the patients they are designed to help.”
Whitfill says Azitra came away from the project with confidence in the feasibility of manufacturing the LBP as the company forges ahead with clinical trials. Ellis, for his part, is satisfied that together the partners efficiently developed a high-quality product according to GMP standards and optimized the production of the LBP.
“After working with Biose industrie to manufacture this product, we’re now working on new formulations, which is a very challenging part of developing LBPs” says Whitfill. “We’re looking at products that are difficult to formulate on the skin because we’re dealing with live microbes. Trying to get room-temperature-stable products is not always easy when using a live organism. Additionally, packaging is a real challenge (maintaining GMP conditions across the whole process). So, as we move forward, we’re collaborating with Biose industrie while developing our own capabilities to look at some innovation and new techniques in this area.”
Ellis believes the future of skin microbiome therapeutics is bright. The project, in fact, has led Biose industrie to invest in ways to formulate new products for skin applications. The CDMO has purchased new equipment, hired R&D engineers, and plans to open a new vertical dedicated to drug product formulation for skin.
“Every project is a new challenge,” says Ellis. “But we are committed to helping our clients achieve their manufacturing goals, so patients can one day receive these important new therapies.”