Accelerate In Vivo CAR-T Development with Our Integrated mRNA IVT & Targeted LNP CRO Solutions

In vivo CAR-T therapy has emerged as a transformative alternative to traditional ex vivo CAR-T products. By directly engineering endogenous T cells inside the patient’s body, this approach eliminates complex leukapheresis, lengthy cell culture, and viral vector-related safety risks, while drastically cutting manufacturing costs and treatment cycles. However, the large-scale advancement of in vivo CAR-T is still hindered by multiple critical technical bottlenecks: insufficient delivery specificity for T cells, low mRNA encapsulation and transfection efficiency, poor formulation stability, inconsistent performance during process scale-up, and challenges in developing scalable targeted delivery systems.

As a professional CRO specializing in custom IVT mRNA synthesis and antibody-conjugated targeted LNP (Ab-tLNP) platforms, Quintara Bio delivers a full-spectrum, one-stop solution covering gene synthesis, plasmid production and linearization, high-purity IVT production, LNP formulation, targeted conjugation, stability optimization and GMP-compliant scale-up. Our maleimide-based antibody conjugation technology and mature mRNA-LNP workflow have been fully validated via in vitro cell assays, non-human primate (NHP) studies and GMP batch production. We help your team break through technical barriers and accelerate the entire R&D pipeline from early formulation screening to preclinical and clinical translation of in vivo CAR-T therapies.

Core Technical Bottlenecks Facing Modern In Vivo CAR-T R&D

Before diving into our solutions, we summarize the most prevalent challenges that restrict the progress of mRNA-LNP based in vivo CAR-T programs, which are also the key pain points our platform is designed to resolve:

Non-specific delivery of conventional LNPs

Standard LNPs predominantly accumulate in the liver after systemic administration, leading to low transfection efficiency in target CD3⁺/CD8⁺ T cells and severe off-target effects. Achieving precise T-cell targeting has become the top priority for in vivo CAR-T delivery systems.

Unstable quality after LNP-antibody conjugation

Many conventional conjugation chemistries cause increased particle size, elevated polydispersity index (PDI), declined encapsulation efficiency (EE) or particle aggregation, which directly damages in vivo delivery activity.

Substandard mRNA quality

Residual dsRNA, high endotoxin and degraded mRNA trigger excessive innate immune responses, reduce CAR protein expression, and interfere with the efficacy and safety evaluation of in vivo CAR-T.

Poor long-term formulation stability

LNPs often lose physicochemical properties and biological activity during refrigerated storage or freeze-thaw cycles, failing to meet the requirements for batch production, transportation and long-term preclinical studies.

Difficult process scale-up

Formulation parameters optimized at lab scale cannot be stably transferred to large-volume or GMP batches, resulting in significant batch-to-batch differences and blocking clinical transformation.

Lack of integrated technical support

Most R&D teams need to cooperate with multiple suppliers for mRNA synthesis, LNP preparation and targeted modification, leading to disjointed workflows, prolonged project timelines and uncontrollable overall quality.

Our End-to-End CRO Service Portfolio for In Vivo CAR-T

We build a closed-loop technical chain from CAR-mRNA synthesis to targeted LNP delivery, fully matching the life-cycle R&D demands of in vivo CAR-T projects. Our services are divided into core modules and extended targeted modification capabilities:

High-Performance Custom IVT mRNA Service for CAR Constructs

We provide tiered IVT mRNA products (screening grade / research grade / preclinical grade) tailored for CAR mRNA, bispecific CAR mRNA and other related transcripts, with industry-leading quality indicators:

· Strict impurity control: dsRNA content, endotoxin, effectively mitigating in vivo immune interference;

· Excellent molecular integrity: high mRNA integrity, high capping efficiency to ensure high and sustained CAR protein expression;

· Comprehensive molecular customization: Support adjustable poly(A) tails, multiple modified NTPs and FTO-compliant capping systems to optimize mRNA stability and immunogenicity;

· Flexible production scale: Output ranges from 0.2 mg to g-scale, fully adapting to early screening, in vitro verification and in vivo animal studies.

Our IVT workflow is compatible with all mainstream CAR sequence designs and lays a solid material foundation for subsequent LNP encapsulation.

Standard LNP Encapsulation & Formulation Development

Based on mature microfluidic manufacturing technology, we develop and optimize LNP formulations for CAR-mRNA delivery:

· Rich lipid library: With practical experience in developing more than 25 novel ionizable lipids, we can screen the optimal lipid combinations according to different in vivo administration routes and application scenarios;

· Stable core performance: The average encapsulation efficiency of the platform exceeds 90%, the average PDI is as low as 0.1, and the maximum mRNA concentration of formulations reaches 3.8 mg/mL;

· Full scalability: Processes can be seamlessly scale-up from 5 mL lab scale to L-scale preclinical batches, with consistent particle size, PDI and EE across all scales. This capability has been verified in over 20 IND-enabling mRNA-LNP projects.

Mature Maleimide-Based Antibody Conjugation Platform (Ab-tLNP): Core Technology for T-Cell Targeting

To solve the liver tropism issue of traditional LNPs, we have established a robust maleimide-based conjugation platform to generate T-cell targeted LNPs (tLNPs), which is the key enabling technology for in vivo CAR-T:

· Wide compatibility of antibody formats: Support conjugation of IgG, VHH, scFv and bispecific antibodies (e.g., CD3, CD8 antibodies) for specific binding to T-cell surface markers;

· Ultra-high conjugation efficiency: The average antibody conjugation positive rate is over 90%, guaranteeing reliable in vivo targeting capability;

· Minimal impact on LNP properties: After conjugation, the particle size, PDI and mRNA encapsulation efficiency remain stable, without particle aggregation or performance attenuation;

· Complete analytical system: Equipped with NanoFCM, HPLC, ELISA and other testing platforms to quantitatively analyze conjugation efficiency, antibody modification copy number, and particle distribution.

Streamlined Ab-tLNP process workflow ensuring robust process performance, key product quality attributes, and excellent scalability.

Validated Technical Performance: In Vitro, In Vivo & GMP Batch Data

All our technologies are supported by systematic experimental data, proving reliable performance for in vivo CAR-T development:

Precise T-Cell Targeting In Vitro

We encapsulated tdTomato reporter mRNA into CD8/CD3 conjugated tLNPs and conducted delivery tests using human peripheral blood mononuclear cells (PBMCs):

· CD8-targeted tLNPs achieved over 80% positive expression rate in CD8⁺ T cells at a low dose, while showing negligible transfection in CD4⁺ T cells, demonstrating excellent cell specificity;

· CD3-conjugated tLNPs presented dose-dependent T-cell targeting activity, which can be flexibly adjusted according to experimental requirements.

in vitro evaluation of T-cell targeting using CD3/CD8 conjugated tLNPs. tdTomato mRNA expression in human PBMCs following treatment with (A) CD8-tLNPs and (B) CD3-tLNPs

Potent In Vivo Efficacy in Non-Human Primates (NHP)

We delivered CD20-CD19 bispecific CAR-mRNA via CD8-tLNPs to NHPs with a single intravenous dose of 1.0 mg/kg:

· Systemic B-cell depletion was observed rapidly: B cells in peripheral blood were nearly undetectable within 12 hours post-administration, and the depletion state persisted for 3 days;

· B-cell recovery only started on Day 7, fully verifying the strong in vivo activity of our targeted LNP platform for in vivo CAR-T.

CD8-tLNP-mediated delivery of CD20-CD19 bispecific CAR-mRNA in NHPs. Longitudinal monitoring of systemic B-cell counts in peripheral blood following a single 1.0 mg/kg dose.

Excellent Long-Term Stability

We evaluated the stability of tLNPs under low-temperature storage across two different buffer systems for up to 60 days:

· After 7, 14, 30 and 60 days of storage, the particle size and PDI of tLNPs remained stable, with no significant aggregation;  

· The T-cell transfection efficiency of stored tLNPs in blood and spleen was well maintained, confirming that the formulation can support long-term storage and repeated animal experiments.

Data of tLNP stability in two buffer systems. The stability is further validated by in vivo transfection efficiency changes of T-cells in blood and in spleen.

GMP Batch Consistency (Key Release Indicators)

Three independent GMP batches of CD8-tLNPs loaded with bispecific CAR-mRNA were produced for scale-up verification. Core quality attributes showed outstanding batch-to-batch consistency:

Why Choose Us as Your Exclusive CRO Partner for In Vivo CAR-T?

One-stop integrated solution, streamline your R&D workflow

We integrate CAR-mRNA IVT synthesis, LNP formulation, antibody targeted conjugation, full-characterization QC and process scale-up into one platform. You no longer need to coordinate multiple suppliers, which greatly shorten your project cycle and simplify your technical management.

Solve core pain points of targeted delivery

Our proprietary maleimide-based conjugation technology realizes high-efficiency antibody coupling while retaining all original advantages of LNPs. It fundamentally addresses the poor specificity of traditional delivery systems and empowers precise in vivo T-cell engineering.

Full life-cycle quality control

From raw material preparation, production process monitoring to final batch release, we implement tiered QC strategies matching different R&D stages (screening / research / preclinical / GMP). Every batch is accompanied by complete test reports to ensure data traceability.

Unmatched scalability for clinical transformation

Our lab-scale processes can be directly transferred to GMP production. The stable performance of large-scale batches eliminates the major risk of performance drift during scale-up, paving a smooth path from preclinical research to clinical trials for your in vivo CAR-T candidates.

Rich project experience and track records

Our technical team has accumulated extensive practical experience in cancer immunotherapy, in vivo cell therapy and bispecific CAR design. We can provide professional technical suggestions for sequence optimization, formulation selection and administration strategy based on your project goals.

Outlook

In vivo CAR-T is reshaping the landscape of cell immunotherapy, and high-quality CAR-mRNA and T-cell targeted LNPs are the two cornerstones of its success. While huge market opportunities lie ahead, technical barriers in delivery, stability and scale-up still slow down many R&D programs.

Leveraging our mature IVT mRNA platform, universal LNP formulation technology and industry-leading antibody conjugation system, we provide customized, end-to-end CRO services for in vivo CAR-T projects at every stage. Whether you are conducting early candidate screening, in vitro mechanism verification, NHP in vivo efficacy evaluation or GMP process development, we can tailor the most suitable solutions for you.

Contact our technical team today to discuss your in vivo CAR-T R&D demands. Let us accelerate your project progress and jointly advance the clinical application of next-generation mRNA cell therapies.