In the rapidly evolving world of microbiome therapeutics, success rarely comes from scientific innovation alone. Bringing a novel live biotherapeutic product (LBP) from academic discovery to clinical validation requires years of collaboration, technical problem-solving, regulatory rigor, and manufacturing expertise.
The long-standing partnership between Siolta Therapeutics and Biose Industrie provides a compelling example of how biotechnology innovators and specialized manufacturing partners can work together to transform groundbreaking science into potential medicines.
Today, that collaboration has reached a major milestone. Siolta’s lead therapeutic candidate, STMC-103H, recently demonstrated encouraging Phase 2 clinical results in infants at risk of developing allergic diseases, representing one of the most advanced examples of a defined-strain microbiome therapy being evaluated for disease prevention rather than treatment.
A New Approach to Preventing Allergic Disease
Siolta Therapeutics was founded to address one of the most significant unmet needs in pediatric medicine: the prevention of allergic diseases before they develop.
Originating from pioneering research conducted in the laboratory of Susan Lynch at the University of California San Francisco, the company was built upon a striking observation. Infants who later developed conditions such as atopic dermatitis, food allergies, and asthma consistently lacked certain beneficial gut bacteria during the earliest stages of life.
As similar findings emerged globally, researchers began to understand that the infant microbiome plays a critical role in shaping immune tolerance. The implication was profound: restoring key microbial populations during the first year of life might help prevent allergic diseases from emerging altogether.
This concept challenged traditional therapeutic thinking. Rather than suppressing symptoms after disease onset, Siolta’s strategy focuses on intervening during a narrow developmental window when the microbiome and immune system are co-developing and establishing long-term immune programming.
Their lead candidate, STMC-103H, is a defined consortium of beneficial bacterial strains designed to restore healthy microbiome-immune interactions in at-risk newborns.
Importantly, Siolta has always pursued the pharmaceutical pathway rather than the dietary supplement route.
“These are FDA-regulated therapeutics, not consumer probiotics,” the company has consistently emphasized. For a product intended for newborn infants, pharmaceutical-grade controls, clinical evidence, and GMP manufacturing were considered essential from the outset.
Finding the Right Manufacturing Partner
When Siolta initiated its collaboration with Biose in early 2019, both organizations were at very different stages of their growth journeys.
Siolta had generated promising early data and was preparing for a large proof-of-concept clinical study. The company possessed deep expertise in microbiology and had manufactured initial clinical material internally, but the next phase of development required a very different level of manufacturing capability.
The planned Phase 1b/2 study would require more than 100,000 doses of clinical material, substantial scale-up of fermentation processes, and long-term stability suitable for a multi-year clinical program.
At the same time, Biose was emerging as one of the few CDMOs globally focused specifically on live biotherapeutic manufacturing.
The collaboration began with a comprehensive technology transfer, encompassing culture media, growth parameters, analytical methods, release testing strategies, and manufacturing know-how developed by Siolta’s scientific team.
What started as a manufacturing partnership quickly evolved into a true co-development effort.
Growing Together
The Biose–Siolta relationship mirrors the broader evolution of the microbiome therapeutics industry itself.
When the program began, Biose employed fewer than 100 people and operated a single large-scale fermentation line. Today, the company has grown to nearly 400 employees and operates one of Europe’s most advanced microbiome manufacturing platforms, integrating GMP fermentation, downstream processing, lyophilization, formulation, and drug product manufacturing under one roof.
As Siolta advanced its clinical program, Biose expanded its capabilities in parallel.
The project progressed from small-scale fermentations performed internally at Siolta to industrial-scale production campaigns involving fermentations of up to 3,500 litres. Simultaneously, the dosage form evolved from an early liquid oral formulation to a pharmaceutical-grade solid oral product suitable for long-term administration in infants.
These transitions required extensive analytical redevelopment, stability studies, packaging evaluations, and process optimization.
The Challenge of Manufacturing Novel Anaerobic Therapeutics
Manufacturing live bacterial therapeutics remains one of the most technically demanding areas of modern biopharmaceutical production.
Unlike conventional biologics, many microbiome-derived therapeutic strains are highly sensitive to environmental conditions, particularly oxygen exposure.
Several strains within the STMC-103H consortium belong to this category of strict anaerobes—organisms that can be severely damaged by oxygen exposure during manufacturing.
The challenge extended far beyond simply growing the bacteria.
The Biose and Siolta teams had to develop robust GMP processes capable of:
- Achieving high-density bacterial growth
- Maintaining viability during harvest and concentration
- Preserving activity throughout freeze-drying
- Ensuring long-term stability during storage
- Delivering consistent potency over the entire duration of a clinical study
This required years of iterative process development, media optimization, and analytical innovation.
Together, the teams developed specialized culture media, optimized fermentation parameters, and established potency methods capable of measuring difficult-to-culture gut bacteria under pharmaceutical conditions.
Learning from Failure
One of the defining moments in the collaboration came when a particularly oxygen-sensitive strain behaved unexpectedly during scale-up.
The organism demonstrated excellent growth characteristics during fermentation, achieving the required biomass and viability targets. However, significant viability losses were observed during downstream processing.
Rather than treating the issue as a manufacturing failure, both organizations approached it as a scientific problem to be solved collaboratively.
The teams returned to scaled-down development models, investigated stress responses, evaluated oxygen exposure throughout the process, and redesigned critical manufacturing steps.
A key insight emerged: maintaining anaerobic conditions for longer during downstream processing substantially improved survival.
The resulting process redesign ultimately delivered a robust manufacturing strategy with significantly improved downstream recovery and stability.
The experience became an important example of how progress in the LBP field is often driven by systematic learning rather than straightforward process transfer.
A Maturing Industry
The microbiome therapeutics sector has experienced significant fluctuations over the past decade.
Following a period of rapid expansion and investor enthusiasm, the industry entered a phase of consolidation as companies encountered the scientific, regulatory, and manufacturing realities associated with developing live microbial medicines.
Many programs struggled with reproducibility, potency measurement, strain stability, and large-scale manufacturing.
For complex multi-strain products, these challenges become even greater.
Yet despite these hurdles, the field continues to mature.
Regulatory agencies have become increasingly experienced in evaluating live biotherapeutics, while specialized manufacturers such as Biose have developed the infrastructure and expertise needed to support advanced clinical programs.
The Biose–Siolta collaboration demonstrates that progress in this emerging modality depends on long-term partnerships built around shared scientific understanding and operational execution.
“When we began working with Siolta in 2019, both organizations were helping define what the future of live biotherapeutics could look like. Over the years, we have faced every challenge imaginable, from scaling highly oxygen-sensitive anaerobes to ensuring long-term stability and pharmaceutical-grade reproducibility. Seeing this program generate positive Phase 2 results is incredibly rewarding because it demonstrates that sustained collaboration between innovative biotech companies and specialized CDMOs can translate ambitious science into meaningful clinical outcomes.”
says Adrien Nivoliez, Chief Executive Officer, Biose Industrie
Clinical Validation: Positive Phase 2 Results for STMC-103H
The collaboration reached a major milestone with the recent completion of the Phase 2 ADORED study evaluating STMC-103H in infants at risk of allergic disease.
The randomized, double-blind, placebo-controlled trial enrolled 238 newborns across 30 sites in the United States and Australia. Infants received daily treatment during their first year of life and were subsequently followed for an additional year.
The results were among the most encouraging clinical outcomes reported to date in the microbiome therapeutics field:
- A 64% reduction in physician-diagnosed atopic dermatitis among infants who completed the full year of treatment compared with placebo (23.3% vs. 43.1%; p=0.005).
- A 77% reduction in physician-diagnosed food allergy at one year in treated infants compared with placebo (4.7% vs. 16.7%; p=0.02).
- Significant prolongation of time to onset of atopic dermatitis and reductions in total serum IgE levels.
- A 53% reduction in atopic dermatitis risk among infants who completed at least six months of treatment.
- STMC-103H was reported to be safe and well tolerated, with no meaningful differences in serious adverse events compared with placebo.
For a field that has often been judged on promise rather than clinical outcomes, these results represent a significant achievement.
Perhaps most importantly, they support a fundamentally new therapeutic concept: that targeted manipulation of the microbiome during early life may alter immune development sufficiently to prevent disease before symptoms emerge.
“The positive Phase 2 results from the ADORED study represent much more than a clinical milestone. They provide evidence that intervening during the earliest stages of life may fundamentally alter the trajectory of immune development. Our vision has always been to move beyond treating allergic disease and instead prevent it before it begins. Achieving this would not have been possible without manufacturing partners willing to tackle the unprecedented challenges associated with developing a first-in-class live biotherapeutic product for newborn infants.”
explains Nikole Kimes, CEO, Siolta Therapeutics
Looking Ahead
The journey from microbiome discovery to a successful preventive therapeutic remains far from complete. Phase 3 development, regulatory review, and eventual commercialization still lie ahead.
However, the progress achieved by Siolta and Biose illustrates what can be accomplished when scientific innovation is matched with long-term manufacturing expertise and a willingness to solve unprecedented challenges together.
More than 200 newborns have already received Biose-manufactured STMC-103H under an FDA-regulated clinical program. For both organizations, that achievement represents more than a manufacturing milestone—it is evidence that the microbiome field is steadily moving from scientific promise toward meaningful clinical impact.
As the industry continues to mature, partnerships like Biose and Siolta’s may serve as a blueprint for how the next generation of live biotherapeutic medicines reaches patients worldwide.