Stablepharma’s room temperature-stable SPVX02 vaccine marks a milestone in vaccine science after Phase 1 results published in The Lancet eClinicalMedicine support fridge-free vaccine storage.
Written By: Kirti Kumbhar, M. Pharm (QA)
Reviewed By: Pharmacally Editorial Team
Stablepharma has announced the publication of Phase 1 clinical trial results for SPVX02, its investigational room temperature-stable tetanus-diphtheria (Td) vaccine, in The Lancet eClinicalMedicine. The peer-reviewed publication reports that SPVX02 demonstrated a favorable safety profile and immunogenicity comparable to licensed Td vaccines in healthy adults, providing clinical support for the company’s proprietary StablevaX™ thermostabilization technology.
Unlike conventional vaccines that require continuous refrigeration, SPVX02 is designed to remain stable at ambient temperatures while also being resistant to freezing. If confirmed in larger clinical studies, this approach could reduce dependence on cold-chain logistics, improve vaccine accessibility, and decrease vaccine wastage, particularly in resource-limited settings.
About Tetanus and Diphtheria
Tetanus and diphtheria remain important vaccine-preventable bacterial diseases worldwide. Although effective vaccines have substantially reduced disease burden, maintaining vaccine potency depends on an uninterrupted cold chain from manufacturing through administration.
Cold-chain interruptions can reduce vaccine availability, increase distribution costs, and contribute to vaccine wastage, particularly in regions with limited refrigeration infrastructure. Developing thermostable vaccines is therefore considered an important strategy to improve global immunization programs.
About SPVX02 and StablevaX Technology
SPVX02 is a lyophilized, room temperature-stable reformulation of Tetadif, a WHO-prequalified tetanus-diphtheria vaccine manufactured by BB-NCIPD, Bulgaria.
Using Stablepharma’s proprietary StablevaX technology, the vaccine is designed to remain stable at ambient temperatures while remaining resistant to accidental freezing. According to the published clinical study, SPVX02 demonstrated stability for at least 18 months at temperatures up to 30°C, while Stablepharma reported ongoing real-time stability data supporting stability for 24 months at 30°C, with studies continuing toward a 48-month target.
The technology aims to reduce dependence on refrigerated storage and transportation while improving vaccine availability worldwide.
Phase 1 Study Design
The published study was a multicenter, blinded, randomized Phase 1 clinical trial that enrolled 60 healthy adults aged 18 to 55 years who had received tetanus and diphtheria vaccination more than 10 years before enrollment.
Participants were randomized to receive either SPVX02 or one of two licensed comparator vaccines (Tetadif or diTeBooster). The primary objectives were to evaluate the vaccine’s safety and tolerability, while secondary assessments included immunogenicity measured by protective tetanus and diphtheria antibody responses 28 days after vaccination.
The trial is registered under ISRCTN98920861.
Key Clinical Findings
The Phase 1 study demonstrated that SPVX02 achieved a safety profile and immune responses comparable to licensed tetanus-diphtheria vaccines while providing clinical evidence that an aluminium-adjuvanted vaccine can be reformulated into a fridge-free, freeze-resistant product without compromising immunogenicity.
No vaccine-related serious adverse events were reported during the study, and reactogenicity was predominantly mild to moderate across treatment groups.
By Day 28, all participants who received SPVX02 achieved protective antitoxin concentrations against both tetanus and diphtheria, demonstrating immune responses comparable to those observed with the licensed comparator vaccines.
The investigators noted that the analyses were descriptive and that the study was not powered for formal statistical comparisons between treatment groups.
Safety Profile
SPVX02 was generally well tolerated throughout the study. No vaccine-related serious adverse events were reported, and most local and systemic reactions were mild to moderate in severity, supporting a safety profile comparable with currently licensed Td vaccines.
Study Limitations
As a Phase 1 clinical trial, the study was designed primarily to evaluate safety, tolerability, and immunogenicity rather than clinical efficacy. The trial enrolled a relatively small number of healthy adult participants, and the analyses were descriptive without formal hypothesis testing.
Larger clinical studies will be required to confirm these findings across broader populations and further establish the vaccine’s clinical performance.
Expert Perspective
Professor Saul Faust, lead investigator of the Phase 1 study, noted that maintaining vaccines within the cold chain remains one of the greatest challenges for global immunization programs. He stated that the findings suggest SPVX02 could remain safe and immunogenic without refrigeration, potentially improving vaccine storage and delivery if confirmed in larger studies.
Stablepharma Chief Executive Officer Özgür Tuncer said publication in The Lancet eClinicalMedicine provides important independent peer-reviewed recognition of the StablevaX™ platform and supports the company’s broader strategy of developing fridge-free vaccines and other temperature-stable biologics.
Why This Matters for Global Health
Thermostable vaccines have the potential to simplify vaccine storage and distribution by reducing reliance on refrigerated transport and storage.
This could improve vaccine availability in remote and resource-limited settings, reduce vaccine wastage associated with cold-chain failures, strengthen supply-chain resilience, and lower the environmental impact of vaccine distribution.
According to Stablepharma, reducing cold-chain requirements may also help decrease the healthcare sector’s carbon footprint by minimizing refrigeration-related energy consumption.
Next Step: Phase 2b Clinical Development
Following the successful completion of the Phase 1 study and publication of the results, Stablepharma has initiated recruitment for a randomized, single-blind, non-inferiority Phase 2b clinical trial.
The study will:
- Enroll approximately 160 healthy adults aged 18 to 60 years
- Be conducted at the Medicines Evaluation Unit (MEU), Manchester
- Further evaluate the safety and immunogenicity of SPVX02 compared with licensed Td vaccines
The company also plans to expand the application of its StablevaX platform beyond vaccines into additional therapeutic areas, including oncology and anti-infective medicines.
Path Forward
Publication of the Phase 1 results in The Lancet eClinicalMedicine represents an important milestone for Stablepharma’s thermostable vaccine platform.
Although the findings are encouraging, SPVX02 remains an investigational vaccine candidate, and larger clinical trials will be necessary to confirm its safety and immunogenicity in broader populations. If future studies are successful, SPVX02 could provide a practical alternative to conventional cold chain-dependent tetanus-diphtheria vaccines while improving vaccine access, reducing distribution costs, and minimizing vaccine wastage worldwide.
References
About the Writer
Kirti Kumbhar (LinkedIn) is an M.Pharm graduate with experience in Quality Assurance at Lupin Limited and a strong interest in clinical research, regulatory affairs, and Trial Master File (TMF) management. She has developed knowledge of regulatory documentation, quality systems, compliance, and healthcare research through her professional experience. Passionate about clinical development and continuous learning, Kirti is committed to supporting high-quality healthcare documentation, regulatory excellence, and research-driven healthcare advancements.