CAR-T Cell Therapy for Mesothelioma: 72% Response Rate in MSKCC Phase I Trial and 5 Active 2026 Studies

CAR-T cell therapy — the engineered immune treatment that revolutionized blood cancers — is beginning to produce meaningful responses in mesothelioma. In the landmark Memorial Sloan Kettering Phase I trial, 72% of mesothelioma patients who received intrapleural mesothelin-targeted CAR-T cells plus pembrolizumab responded to treatment, including two complete metabolic responses [1]. As of early 2026, five CAR-T trials are actively recruiting mesothelioma patients [5].

What Are the Key Facts About CAR-T Cell Therapy for Mesothelioma?

• Engineered immune cells: CAR-T therapy uses a patient's own T cells, genetically modified in a lab to express a chimeric antigen receptor that recognizes a tumor protein and triggers cancer cell killing.
• Primary target: Mesothelin is expressed in roughly 69% of malignant mesotheliomas overall, and 66% of epithelioid tumors, making it the most studied CAR-T target for this disease [8].
• Landmark trial: The MSKCC Phase I trial (NCT02414269), led by Dr. Prasad Adusumilli, enrolled 27 patients with malignant pleural disease — 25 with pleural mesothelioma — and delivered CAR-T cells directly into the pleural cavity [1].
• Response rate: In 11 mesothelioma patients who received CAR-T plus pembrolizumab, the overall response rate was 72%, with 2 complete metabolic responses and 6 partial responses [1].
• Safety profile: Only grade 1–2 adverse events were reported in the MSKCC trial, with no severe cytokine release syndrome and no neurotoxicity [1]. Intrapleural delivery appears to reduce systemic toxicity [9].
• Long-term persistence: CAR-T cells remained detectable in the peripheral blood of 39% of patients (13 of 27) for more than 100 days, and cell persistence was correlated with tumor regression [1].
• Penn experience: A separate University of Pennsylvania Phase I trial of fully humanized huCART-meso cells (4-1BB signaling) observed cytokine release syndrome in 35% of patients and a best response of stable disease in 60% [6].
• Next-generation design: The MSKCC follow-on trial (NCT04577326) uses a mesothelin CAR with a built-in PD-1 dominant-negative receptor, designed to prevent T-cell exhaustion without requiring exogenous checkpoint inhibitors [4].
• Novel epitopes: The NCI TNhYP218 trial (NCT06885697) uses a novel antibody that binds a membrane-proximal region of mesothelin, a different binding site than most existing constructs [3].
• Trial access: Current CAR-T trials are concentrated at MSKCC, the University of Pennsylvania, MD Anderson Cancer Center, the National Cancer Institute, and participating academic sites [5].
• No FDA approval yet: Six CAR-T products are FDA-approved for blood cancers, but none are approved for mesothelioma or any other solid tumor as of April 2026 [2].
• ASCO guidelines: The 2025 ASCO guideline update for pleural mesothelioma treatment includes updated immunotherapy recommendations, but CAR-T remains investigational and is not yet part of formal treatment guidelines [15].

How Does CAR-T Cell Therapy Work for Mesothelioma?

CAR-T cells are a patient's own T cells that have been genetically engineered in a laboratory to express a synthetic protein called a chimeric antigen receptor. The receptor combines an antibody-like fragment that recognizes a specific tumor protein with the intracellular signaling machinery of a T cell. When the modified cells encounter their target on a cancer cell, they activate and destroy it, then continue to expand and persist in the body.

For mesothelioma, the target is almost always mesothelin — a 40-kilodalton glycoprotein that is expressed only at low levels on normal mesothelial surfaces but is overexpressed in the majority of epithelioid mesotheliomas [7]. Unlike conventional T cells, CAR-T cells do not require antigen presentation through the major histocompatibility complex, which is an important advantage in mesothelioma because tumor cells can downregulate MHC to evade immune detection [10].

"What makes CAR-T different from traditional treatment is that we're not just giving a drug — we're giving a living therapy," says David Foster, Director of Client Services at Danziger & De Llano and host of the MESO Podcast. "The engineered cells can expand, persist, and provide ongoing tumor surveillance. That is fundamentally different from chemotherapy, which is a fixed exposure."

Most mesothelioma CAR-T programs use second-generation receptors with either a CD28 or a 4-1BB co-stimulatory domain [7]. MSKCC uses a CD28-based construct, while the University of Pennsylvania program employs a 4-1BB design [6]. Newer generations incorporate additional features — such as secreted cytokines or built-in checkpoint resistance — that are designed to overcome the harsh tumor microenvironment of solid cancers [13].

What Did the MSKCC Phase I Trial Reveal?

The Memorial Sloan Kettering trial (NCT02414269), led by Dr. Prasad Adusumilli, is the most important mesothelioma CAR-T study to date [1]. Twenty-seven patients — 25 with malignant pleural mesothelioma — received intrapleural infusions of autologous mesothelin-targeted CAR-T cells at doses ranging from 0.3 million to 60 million cells per kilogram. Eighteen of the patients also received the anti-PD-1 drug pembrolizumab to help rescue exhausted CAR-T cells [1].

The results were landmark for solid-tumor CAR-T. In a subset of 11 evaluable mesothelioma patients who received both CAR-T and pembrolizumab, the overall response rate was 72%, including 2 complete metabolic responses and 6 partial responses. Among the 16 patients who received lymphodepleting chemotherapy before CAR-T infusion, 12-month overall survival was 80.2%. PD-L1 expression did not predict response — 6 of 8 responses occurred in PD-L1-low patients, which is striking because PD-L1 status typically correlates with checkpoint inhibitor benefit [1].

"A 72% response rate in mesothelioma is remarkable, even in a small Phase I subset," Foster explains. "Most patients diagnosed with pleural mesothelioma have median survival measured in single-digit months. If even a fraction of those responses prove durable in larger trials, this could meaningfully change the treatment landscape."

Safety was equally encouraging. The trial reported only grade 1–2 adverse events, with no severe cytokine release syndrome and no immune effector cell-associated neurotoxicity syndrome [1]. This mild toxicity profile stands in sharp contrast to CAR-T for blood cancers, where severe cytokine release syndrome can occur in up to 100% of pediatric leukemia patients [2]. Researchers believe regional delivery into the pleural space and the relatively lower tumor burden accessible to CAR-T cells are both contributing factors [9].

Why Is CAR-T Delivered Directly into the Pleural Space?

Pleural mesothelioma is a surface-based malignancy that grows along the lining of the chest cavity. That anatomy makes it uniquely accessible to local therapy through image-guided catheter placement, which is exactly how CAR-T cells are delivered in the MSKCC trial [1]. Preclinical studies at MSKCC showed that intrapleurally delivered CAR-T cells "vastly outperformed" systemically infused T cells in orthotopic mesothelioma models [9].

Both routes delivered similar numbers of T cells to the pleural tumor, but intrapleurally delivered cells achieved superior activation, tumor eradication, and persistence. Critically, regionally delivered CAR-T cells also circulated systemically and could control tumors at distant sites — effectively turning the pleural cavity into what the MSKCC researchers call a "regional distribution center" for engineered immune cells [9].

The safety case for regional delivery is equally strong. Two cases of severe pulmonary toxicity were reported in an unrelated study that used intravenous infusion of a highly active fully human mesothelin CAR [12]. By contrast, the MSKCC intrapleural trial reported no severe toxicity [1], and the FAP-targeted CAR-T Phase I trial (which also used intrapleural delivery) reported no treatment-related adverse events in three mesothelioma patients [11].

What Clinical Trials Are Currently Recruiting Mesothelioma Patients?

As of January 2026, 93 mesothelioma clinical trials are actively recruiting worldwide, with 32 testing immunotherapy approaches and 5 specifically evaluating CAR-T cell therapy [5]. No mesothelioma CAR-T program has yet advanced beyond Phase I or Phase II, but several next-generation studies are pushing the field forward:

• NCT04577326 (MSKCC next-generation): This study is testing M28z1XXPD1DNR, a mesothelin CAR engineered with a built-in PD-1 dominant-negative receptor [4]. The receptor acts as a decoy, preventing PD-1-mediated T-cell exhaustion without requiring exogenous anti-PD-1 antibody therapy.
• NCT06885697 (NCI TNhYP218): Led by Dr. Raffit Hassan at the National Cancer Institute, this trial tests a novel antibody (hYP218) that binds a membrane-proximal epitope of mesothelin — a different binding site than most existing constructs [3]. It also uses Tnaïve/stem-cell-memory T-cell populations designed for improved persistence.
• NCT06051695 (EVEREST-2): A logic-gated CAR-T evaluated at multiple sites that incorporates HLA-based safety mechanisms to improve tumor specificity and reduce on-target off-tumor toxicity.
• NCT05703854 (CAR.70 NK cells at MD Anderson): A CAR-NK cell trial that targets CD70 using natural killer cells engineered with a CAR, offering potential off-the-shelf manufacturing advantages.
• NCT06256055 and NCT06726564: Two additional academic Phase I studies evaluating CAR-T approaches for mesothelioma, with enrollment concentrated at U.S. cancer centers.

Patients interested in enrolling can search ClinicalTrials.gov for current mesothelioma trials, or work with a mesothelioma specialist who can identify trials matching their disease stage, prior treatment, and geographic location.

Why Is CAR-T Harder in Solid Tumors Like Mesothelioma?

CAR-T therapy has achieved extraordinary results in hematologic malignancies. Six FDA-approved CAR-T products target either CD19 or BCMA in leukemia, lymphoma, and multiple myeloma, and complete response rates can reach 90% in pediatric B-cell acute lymphoblastic leukemia [2]. Translating that success to solid tumors like mesothelioma faces biological barriers that do not exist in blood cancers.

First, the mesothelioma tumor microenvironment is deeply immunosuppressive. Tumor cells and surrounding stroma secrete TGF-beta, IL-10, and VEGF, and they recruit regulatory T cells, myeloid-derived suppressor cells, and tumor-associated macrophages that actively suppress CAR-T function [13]. Second, dense stromal matrix and tumor hypoxia physically limit CAR-T access to cancer cells [13]. Third, mesothelin expression is not uniform — even in epithelioid mesothelioma, only about 37% of tumors show diffuse expression in more than half of tumor cells, which creates a risk of antigen-negative escape [8].

"The biology of mesothelioma is different from leukemia or lymphoma in almost every way that matters for cell therapy," Foster notes. "Researchers have had to engineer their way around multiple barriers at once — exhaustion, trafficking, heterogeneous expression — and the fact that trials are showing any meaningful responses at all is an encouraging sign that the strategy can work in solid tumors."

Engineering solutions to these challenges are advancing rapidly [7]. They include armored CARs that secrete pro-inflammatory cytokines, dominant-negative TGF-beta receptors, CRISPR-edited PD-1 knockout cells, and combination strategies pairing CAR-T with checkpoint inhibitors [10]. Regional delivery — intrapleural for pleural disease, intraperitoneal for peritoneal disease — bypasses the trafficking barrier and appears to be a key reason mesothelioma trials have achieved such favorable safety profiles [9].

How Does CAR-T Compare to Standard Mesothelioma Treatment?

Since October 2020, the first-line standard of care for unresectable malignant pleural mesothelioma has been nivolumab plus ipilimumab, approved by the FDA based on the Phase III CheckMate 743 trial [14]. In that randomized study of 605 patients, dual checkpoint blockade produced median overall survival of 18.1 months, significantly longer than the 14.1 months achieved with platinum-pemetrexed chemotherapy [14] [17]. The benefit was particularly striking in non-epithelioid histology, where chemotherapy performs poorly.

CAR-T cells and checkpoint inhibitors are not competing strategies — they are complementary. Checkpoint inhibitors release the brakes on pre-existing immune responses, while CAR-T provides an engineered, targeted immune response [10]. The two approaches appear to be synergistic in mesothelioma. The MSKCC trial's 72% response rate came from combining intrapleural CAR-T with pembrolizumab [1], and the next-generation MSKCC construct builds checkpoint resistance directly into the CAR [4].

For now, CAR-T is being evaluated in later-line settings — typically after patients have progressed on platinum-based chemotherapy [15]. If confirmatory trials succeed, the therapy could eventually move to earlier lines or be combined with surgical cytoreduction such as pleurectomy/decortication to clear residual disease after surgery [18].

What Does CAR-T Therapy Cost and Who Can Access It?

FDA-approved CAR-T therapies for blood cancers carry list prices between approximately $373,000 and $475,000 per infusion, and total treatment costs — including hospitalization, lymphodepletion, and complication management — can exceed $1 million per patient [2]. Mesothelioma-specific CAR-T is not yet commercially available, and current access is limited to clinical trials at major academic centers, where participation is typically cost-free for enrolled patients [5].

Even within clinical trials, access is tightly constrained by eligibility criteria [3] [4]. Typical inclusion requirements include confirmed mesothelin expression on tumor biopsy, adequate organ function, ECOG performance status of 0–1, and geographic proximity to an enrolling center. Patients with prior severe autoimmune disease or uncontrolled infections are generally excluded. Travel, lodging, and caregiver support are rarely covered by trial sponsors, which creates real financial barriers for many families.

"Clinical trial access is often the limiting factor for our clients," Foster says. "The science is moving fast, but patients need financial stability to pursue experimental options — travel, time off work, caregiver support. That is one reason legal compensation matters so much. A mesothelioma settlement or trust fund claim can make the difference between accepting standard treatment locally and flying to a center running a trial that might help."

Patients and families pursuing treatment should consider both medical and legal strategies in parallel. Asbestos trust fund claims can provide compensation that helps cover travel to trial sites, experimental treatment costs, and living expenses during extended care.

What Should Mesothelioma Patients Do to Explore CAR-T Options?

If you or a loved one has been diagnosed with mesothelioma and is interested in exploring CAR-T cell therapy, there are practical steps to take. First, ensure your diagnosis and staging are complete and your pathology report is available — most trials require mesothelin-positive tumor confirmation via immunohistochemistry before enrollment [8]. Second, consult with a mesothelioma specialist at a comprehensive cancer center, ideally one affiliated with an active CAR-T trial [15].

Third, search ClinicalTrials.gov or speak directly with trial coordinators at MSKCC, the University of Pennsylvania, MD Anderson, or the NCI to confirm current eligibility and enrollment status. Finally, consider the financial picture — even cost-free trial participation still carries travel, lodging, and lost-income burdens that compensation from an experienced mesothelioma attorney can help address.

The broader context is worth keeping in mind. No CAR-T product is yet FDA-approved for mesothelioma [2]. Trial access is limited to a handful of centers. And the cell therapy field is still refining its approach to solid tumors. But the 72% response rate seen in the MSKCC Phase I trial is a real signal [1], and the next generation of trials — with built-in checkpoint resistance, novel antibodies, and logic-gated safety mechanisms — is designed to build on that result [4].

How Can You Take the Next Step?

If you or a loved one has been diagnosed with mesothelioma, understanding all available treatment options — including emerging cell therapies like CAR-T — is critical. Here is how to move forward:

1. Take Our Free Case Evaluation Quiz: Start with our free case evaluation quiz to get personalized information based on your diagnosis, stage, and exposure history.

2. Explore CAR-T and Immunotherapy Trials: Visit ClinicalTrials.gov and search for "CAR-T mesothelioma" or "mesothelin" to find active recruitment at academic centers near you.

3. Consult a Mesothelioma Specialist: Seek care at a comprehensive cancer center or specialty mesothelioma program. Review WikiMesothelioma's CAR-T Cell Therapy page for a plain-language overview you can bring to your oncologist [16].

4. Contact an Experienced Mesothelioma Attorney: Mesothelioma lawsuits and trust fund claims can help cover travel to trial sites, experimental treatment costs, and household expenses during extended care. Call us at (866) 222-9990 for a free consultation. Danziger & De Llano has a 40-plus year track record of securing substantial settlements and verdicts for mesothelioma patients and their families.

References

1. [1] Adusumilli PS et al. A Phase I Trial of Regional Mesothelin-Targeted CAR T-cell Therapy in Patients With Malignant Pleural Disease, in Combination With the Anti-PD-1 Agent Pembrolizumab. Cancer Discovery 2021;11(11):2748-2763.
2. [2] National Cancer Institute. Mesothelioma Treatment (PDQ) — Patient Version.
3. [3] National Cancer Institute. Anti-Mesothelin TNhYP218 CAR T Cells in Mesothelin-Positive Tumors (NCT06885697).
4. [4] ClinicalTrials.gov. Mesothelin-Targeted CAR T-cell Therapy in Patients With Solid Tumors (NCT04577326).
5. [5] ClinicalTrials.gov. Search Results — Mesothelioma Studies.
6. [6] Haas AR et al. Phase I Study of Lentiviral-Transduced huCART-meso Cells in Mesothelin-Expressing Cancers.
7. [7] Weidle UH et al. Mesothelin as a Target for Chimeric Antigen Receptor-Modified T Cells as Anticancer Therapy.
8. [8] Inaguma S et al. Mesothelin Expression in Human Tumors: A Tissue Microarray Study on 12,679 Tumors.
9. [9] Adusumilli PS et al. Regional Delivery of Mesothelin-Targeted CAR T Cell Therapy Generates Potent and Long-Lasting CD4-Dependent Tumor Immunity. Science Translational Medicine.
10. [10] Hassan R et al. Anti-Mesothelin CAR T Cell Therapy for Malignant Mesothelioma.
11. [11] Curioni A et al. A Phase I Clinical Trial of Malignant Pleural Mesothelioma Treated With Locally Delivered Autologous Anti-FAP-Targeted CAR T Cells.
12. [12] Perales-Puchalt A et al. Two Cases of Severe Pulmonary Toxicity From Highly Active Mesothelin-Directed CAR T Cells.
13. [13] Mansour AG et al. CAR T Cell Therapy and the Tumor Microenvironment.
14. [14] FDA. Approval Summary: Nivolumab in Combination With Ipilimumab for the Treatment of Unresectable Malignant Pleural Mesothelioma.
15. [15] Kindler HL et al. Treatment of Pleural Mesothelioma: ASCO Guideline Update. Journal of Clinical Oncology.
16. [16] WikiMesothelioma. CAR-T Cell Therapy.
17. [17] WikiMesothelioma. Immunotherapy for Mesothelioma.
18. [18] WikiMesothelioma. Mesothelioma Treatment.

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