In recent years, therapeutic vaccines targeting virus-associated cancers have gained growing attention, with human papillomavirus (HPV)-induced cervical cancer and oropharyngeal cancer standing out as major focus areas. Peptide-based vaccines, due to their high safety, design flexibility, and ease of manufacturing, are considered promising candidates for therapeutic applications. However, simple peptide antigens generally suffer from low immunogenicity and fail to elicit effective CD8+ cytotoxic T cell responses, making them highly dependent on efficient adjuvants or delivery systems.
Among the many immune adjuvants and delivery materials, R-DOTAP (R-1,2-dioleoyl-3-trimethylammonium-propane), a chiral cationic lipid, has emerged in recent years with unique advantages. R-DOTAP not only forms stable complexes with negatively charged peptide antigens but also directly contributes to immune activation, inducing robust cellular immune responses. In the development of therapeutic HPV peptide vaccines, R-DOTAP has proven to be a dual-function material, serving both as a delivery system and as an adjuvant.
Litchlab has established kilogram-scale stable supply of R-DOTAP, along with full-process service capabilities in process development and pilot-scale manufacturing, providing strong support for global clients from R&D to clinical stages. We are committed to working with partners to accelerate the translation of HPV and other cancer-related vaccines into clinical reality, bringing new breakthroughs to human health.
Peptide antigens are small, prone to degradation, and are often rapidly cleared in vivo. The permanent positive charge of R-DOTAP allows electrostatic complexation with negatively charged amino acid residues in peptide antigens, self-assembling into nanoparticles. These nanoparticles are more stable in vivo and are efficiently taken up by antigen-presenting cells (APCs) such as dendritic cells and macrophages, significantly improving peptide antigen delivery efficiency.
The core objective of therapeutic HPV vaccines is to induce cytotoxic T lymphocyte (CTL) responses against HPV oncogenic proteins such as E6/E7, thereby eliminating infected or transformed cells. Studies show that R-DOTAP strongly promotes antigen cross-presentation through the MHC I pathway in dendritic cells, leading to potent CD8+ T cell activation—an effect difficult to achieve with conventional adjuvants such as alum or certain emulsions.
Compared with conventional DOTAP, the stereochemistry of R-DOTAP confers superior immune activation properties. R-DOTAP nanoparticles stimulate innate immune signaling pathways and induce cytokine secretion, providing the “second signal” required for adaptive immune establishment. This combined “delivery + adjuvant” mechanism makes R-DOTAP far more effective than traditional lipids in enhancing immune responses in HPV peptide vaccines.
Multiple studies and clinical trials have demonstrated that R-DOTAP–based HPV peptide vaccines can induce broad, functional T cell responses in humans with favorable safety profiles. Compared with other lipid carriers, R-DOTAP shows clear superiority in eliciting cellular immunity, making it particularly suitable for therapeutic vaccine applications.
Stronger Immunogenicity: R-DOTAP demonstrates significantly stronger T cell activation in comparative studies, while S-DOTAP shows no effect, highlighting its stereoselective advantage.
Unique Mechanism: Beyond being a delivery vehicle, R-DOTAP itself functions as an immune adjuvant, reducing the need for additional adjuvant components.
High Compatibility with Peptides: The cationic nature of DOTAP aligns perfectly with the anionic properties of peptides, enabling rapid self-assembly into stable complexes with simple processing.
Broad Applicability: Extends beyond HPV peptide vaccines to tumor neoantigen vaccines, viral peptide vaccines, and more.
Mature Large-Scale Synthesis: Established kilogram-scale synthesis and purification routes with stable processes and high batch-to-batch consistency.
High Purity, Low Impurities: Multi-step refinement removes by-products and residual solvents, ensuring pharmaceutical-grade lipid purity.
Comprehensive Quality System: Products can be manufactured under GMP guidelines with full quality documentation (HPLC, NMR, MS, residual solvent analysis, etc.).
Flexible Supply Chain: Supports delivery from gram-scale R&D samples to kilogram-scale pilot batches, covering all development stages.
Formulation Optimization: Tailored to peptide antigen properties, optimizing R-DOTAP/antigen ratios, particle size, and charge balance to maximize immune efficacy and stability.
Process Parameter Exploration: Establishes standardized complexation methods, including solvent systems, mixing modes, and time/temperature controls, ensuring reproducibility.
Stability Studies: Provides accelerated and long-term stability assessments, lyophilization protectants, and storage condition optimization.
Immunological Evaluation Support: In collaboration with academic and CRO partners, offers preclinical immunogenicity testing in animal models to guide formulation selection.
Scale-Up Equipment: Equipped with micro-mixing systems and continuous flow devices to ensure seamless transition from milliliter to liter and kilogram scales.
Batch Consistency: Rigorously validated processes guarantee consistent particle size distribution, complexation efficiency, and zeta potential across scales.
Clinical Sample Preparation: Supports production of preclinical and clinical-grade trial materials for Phases I–III, reducing cost and time-to-clinic.
Complete Documentation: Provides DMF (Drug Master File) and technical packages to support regulatory submissions in China, the U.S., and EU markets.
Global Regulatory Experience: Extensive ICH-compliant project experience ensures alignment with FDA, EMA, and NMPA requirements.
Long-Term Supply Assurance: Guarantees consistent, reliable raw material supply across the entire product lifecycle.
End-to-End Support: From raw material supply, formulation optimization, process development, to pilot-scale production.
Accelerated Timelines: Parallelized development strategies shorten the transition from lab validation to clinical manufacturing.
Customized Services: Flexible delivery of standardized or tailor-made R-DOTAP materials and delivery system solutions based on project needs.
“DP7-C/DOTAP Liposomes Enhance the Anti-Tumor Efficacy of Oncolytic Adenovirus”
Summary: DP7-C/DOTAP liposomes served as adenovirus carriers, improving transduction efficiency in CAR-low tumor cells and protecting adenoviruses from neutralizing antibodies. In vivo mouse models confirmed that DP7-C/DOTAP enhanced oncolytic adenovirus anti-tumor efficacy, doubling tumor inhibition rates compared with virus alone.
As a chiral lipid with dual delivery and adjuvant functionality, R-DOTAP has demonstrated unique advantages in HPV peptide vaccine development. It not only significantly enhances antigen delivery and T cell immunity but also activates innate immune pathways to provide an optimal immunological environment for therapeutic vaccines.
With the rising demand for HPV-related cancer treatments, R-DOTAP is poised to become a key lipid component in peptide vaccine formulation design. Backed by Litchlab’s kilogram-scale production and full-process development services, R-DOTAP is paving the way for the next generation of therapeutic cancer vaccines.
