In vivo CAR-T therapy: Clinical data, EsoBiotec platform, and the future of cell therapy

Introduction: The Next Step of CAR-T Is Not “Better” — It’s “Simpler”

Over the past decade, CAR-T therapy has proven that we can treat cancer with engineered immune cells.

But the real bottleneck is never efficiency, but rather:

• Too high cost

• The manufacturing process is too slow

• Patients can't wait

The essence of traditional CAR-T is actually "personalized cell manufacturing".

Now, a more fundamental question has arisen:

What if CAR-T didn't need to be manufactured at all?

This is the direction revealed by the latest clinical research:

in vivo CAR-T therapy

Technological essence: Turning the human body into a CAR-T manufacturing plant

The traditional CAR-T (ex vivo CAR-T) process is essentially a "personalized cell manufacturing" process:

1. Leukapheresis (white blood cell separation)

   → Collect peripheral blood mononuclear cells (PBMCs) from the patient and isolate T cells.

2. Ex vivo gene engineering

   → CAR genes are typically introduced into T cells using lentiviral or retroviral vectors.

3. Cell expansion

4. Lymphodepletion (lymphatic drainage chemotherapy)

   → Reduce the number of immune cells in the body before infusion to promote CAR-T proliferation.

5. Infusion (CAR-T cell infusion)

The core challenge of this entire process lies in:

It has a long manufacturing time, high cost, and patient-to-patient variability.

In contrast, in vivo CAR-T therapy adopts a completely different strategy:

👉 Gene delivery and T cell engineering can be completed directly in the body.

• Leukapheresis is not required

• No need for ex vivo manufacturing process

• No cell proliferation is required.

📌 Key Shift:

CAR-T cells are no longer "manufactured products," but rather "cells generated within the body."

Technical Analysis: How does EsoBiotec achieve in-vivo CAR-T Therapy?

🏢 Company: EsoBiotec (acquired by AstraZeneca)

This technology comes from:

👉 EsoBiotec (Belgium)

• Focus on vivo cell engineering

• Acquired by AstraZeneca in 2025.

👉 Representative:

Major pharmaceutical companies are betting on "de-manufacturing" cell therapy.

Carrier: Engineered lentiviral vector (ESO-T01)

The core technology is:

👉Highly engineered lentiviral vector

Key engineering

1️⃣ T cell targeting

• anti-TCR nanobody

  → Allow vectors to preferentially infect T cells

2️⃣ Immune escape

• CD47

  → Inhibit macrophage phagocytosis

3️⃣ Reduces immunogenicity

• MHC-I knockout

4️⃣ Precise Expression

• T cell-specific promoter

  → Restrict CAR expression to T cells only

📌 Core Concepts:

cell-type specific gene delivery system

Mechanism: How is an in vivo CAR-T generated in vivo?

Step 1. Intravenous infusion

Provide an engineered lentiviral vector with a single IV infusion.

Step 2. Cell targeting

Through anti-TCR nanobody, the vector preferentially binds to T cells.

Step 3. Gene delivery and integration

The lentiviral vector integrates the CAR gene into the T cell genome.

Step 4. In vivo expansion and tumor targeting

T cells transform into CAR-T cells, which then proliferate and attack tumors in the body.

📌 Core Insights:

The manufacturing process of CAR-T is transferred to the human body.

Analysis of Clinical Trial Design

Trial Design

• Phase 1

• single-arm

• open-label

• primary endpoint: safety

• Secondary endpoints: efficacy, pharmacokinetics (PK), pharmacodynamics (PD)

Patient Population

• Multiple lines of treatment failed (median 3 lines)

• I have used proteasome inhibitors, IMiDs, and anti-CD38 antibodies.

• high tumor burden

• high-risk cytogenetics

• extramedullary disease

Administration

• Single IV infusion

• No need for leukapheresis

• No need for lymphodepletion (lymphatic drainage chemotherapy)

Key differences

👉 Infusion can be completed in approximately 8 hours.

(Traditional CAR-T takes about 2–4 weeks)

PK / PD: A brand new dynamic system

CAR-T expansion kinetics

• Approximately day 4–6

• Days 10–14: Peak

• It can reach approximately 59% of CD3+ T cells

Vector kinetics

• It will last briefly (approximately day 2–4).

👉 Key Insights:

vector is transient

CAR-T is a continuous process.

Biphasic immune response

1️⃣ Early innate immune activation

2️⃣ late adaptive immune response (CAR-T expansion)

👉 Feedback:

The overlapping mechanism of gene therapy + cell therapy

Safety and Key Observations

• CRS (Cytokine Release Syndrome)

• ICANS (Immune effector cell-associated neurotoxicity syndrome)

• cytopenia (low blood cell count)

Key observations:

In vivo CAR-T toxicity exhibits a biphasic pattern, corresponding to vector-induced innate activation and CAR-T expansion.

Clinical strategy insight

Using steroid prophylaxis (steroid pretreatment):

• It can reduce toxicity

• Does not affect efficiency

Display:

Efficacy and toxicity can be strategically separated.

Clinical results (early but indicative)

In this Phase 1 clinical trial, clinically significant therapeutic signals have been observed:

• The overall response rate (ORR) is 80%.

  → Refers to the proportion of patients who achieve a partial or complete tumor response.

• Multiple patients achieved:

  
  

  • CR (Complete Response)

  • sCR (Stringent Complete Response)

  
  

• MRD negativity (Minimal Residual Disease negativity)

  → Cancer cells cannot be detected at high sensitivity (typically 10⁻⁵).

Of particular note:

MRD negativity was observed even in patients with heavily pretreated and extramedullary disease.

Going deeper: This is a new type of treatment.

Three essential changes

• No need for lymphodepletion

• Using endogenous T cells

• Innate immunity participates in tumor clearance.

👉 This is not an optimization of CAR-T, but a new platform.

Industry impact

💰 Cost restructuring

⏱️ A Revolution in Treatment Time

🧪 Delivery becomes a core competitive advantage

🧬 The Rise of Platform Biotech

👉 Future competition will shift towards:

delivery × platform × strategy

Limitations and Future Problems

• Sample

• Long-term safety unknown

• insertional mutagenesis risk

• Durability remains to be verified.

From technological breakthroughs to strategic implementation: Are you ready?

Technologies like in vivo CAR-T are more than just scientific breakthroughs.

It is changing at the same time:

• Product Strategy

• CMC Logic

• Business Model

But the reality is:

Many teams understand science, but are not yet ready with strategy.

LuTra Studio: Connecting Science, Strategy, and Markets

At LuTra Studio , we focus on helping:

• Biotech startups

• Platform biotech

• Team entering the US market

Transforming cutting-edge technologies into:

👉Feasible product and market strategies

We provide

• Technology Positioning

• CMC / development strategy

• US Market Strategy

• science × business integration

Explore LuTra Studio

Learn More

Quickly compile clinical endpoints (Clinical Endpoints Cheat Sheet)

• ORR (Overall Response Rate) : The percentage of tumors that shrink after treatment.

• CR (Complete Response) : No detectable tumor.

• sCR (Stringent Complete Response) : A more stringent complete buffering mechanism.

• PR (Partial Response) : partial tumor shrinkage

• MRD (Minimal Residual Disease) : Trace amounts of residual cancer cells

• MRD negativity : Cancer-free cells detected with high sensitivity

Conclusion: Cell therapy is becoming a programmable platform.

in vivo CAR-T = gene therapy × cell therapy × delivery science

The real breakthrough of this technology is not just about simplifying the process.

Instead:

👉Transforming cell therapy into an in vivo programmable platform

The question left for you

• What if CAR-T therapy could be administered like a vaccine?

• Will delivery become the biggest competitive advantage?

• Will the next Moderna moment be during cell therapy?

📚 References

1. Zhang, et al. (2026).

   In vivo generation of CAR-T cells using targeted lentiviral delivery for the treatment of relapsed/refractory multiple myeloma.

   Nature Medicine.

   → First-in-human study demonstrating the feasibility of in vivo CAR-T generation via engineered lentiviral vector (ESO-T01), including early clinical efficacy and biphasic immune response.

2. Li, et al. (2025).

   In vivo CAR-T therapy in patients with relapsed/refractory multiple myeloma: a clinical case series.

   The Lancet.

   → Early clinical evidence supporting efficacy and safety of in vivo CAR-T, including responses in patients with extramedullary disease.