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Clinical trials & beyond FDA approval

Experimental Mesothelioma Treatments.

The treatments on this page are not yet standard of care — but many represent the most promising directions in mesothelioma research. For patients at specialist centers, trial enrollment can open access to these therapies years before they reach general oncology practice. This is where the next generation of mesothelioma care is being built.

Ask about trial eligibility Specialists running trials

Cancer research moves in waves. For mesothelioma, the first wave — checkpoint inhibitor immunotherapy — has now reached the FDA-approval shore. The second wave, still cresting in clinical trials, is broader and more targeted: cell-based therapies, virus-based therapies, drugs aimed at specific genetic mutations that drive the disease. A patient entering treatment in 2026 is entering it at an unusually rich moment for trial access.

The mechanics of enrolling in a trial, and who qualifies, depend heavily on where a patient is treated. These therapies are almost exclusively available at NCI-designated cancer centers and dedicated mesothelioma programs — another reason referral to a specialist matters early in the treatment arc. Below, organized by mechanism, are the experimental approaches currently attracting the most attention in the mesothelioma research community.

Ph. II

Cell therapy

Mesothelin-targeted CAR-T cell therapy

CAR-T therapy — which first transformed certain blood cancers — is being actively developed for mesothelioma by engineering a patient's own T cells to recognize mesothelin, a protein highly expressed on mesothelioma tumor cells. Early-phase trials led by Dr. Prasad Adusumilli at Memorial Sloan Kettering have shown encouraging preliminary signals, including responses in heavily pre-treated patients. Administration is often via intrapleural delivery — directly into the pleural space — to improve tumor targeting and limit systemic toxicity.

Leading centerMemorial Sloan Kettering

TargetMesothelin protein

Patient populationRelapsed/refractory pleural

Ph. I/II

Oncolytic viruses

ONCOS-102 & CRS-207 oncolytic virus therapies

Oncolytic viruses are engineered to selectively replicate inside cancer cells, destroying them from within and — critically — triggering a strong immune response that amplifies treatment. For mesothelioma, ONCOS-102, an adenovirus expressing GM-CSF, has been studied in combination with chemotherapy in Phase I/II trials, where it was well-tolerated with no increase in severe adverse events; responders showed increased immune cell infiltration into tumor tissue. CRS-207, a Listeria-based vaccine targeting mesothelin, has produced notable tumor-shrinkage signals in early studies.

DeliveryIntratumoral injection

Often combined withChemotherapy or checkpoint inhibitors

StageMultiple Phase I/II ongoing

Ph. I

Targeted therapy

BAP1-mutation-targeted therapies

Roughly 60% of mesotheliomas carry mutations in the BAP1 (BRCA1-Associated Protein 1) gene, a tumor suppressor. Drugs that exploit this vulnerability — including PARP inhibitors, EZH2 inhibitors, and targeted synthetic lethal approaches — represent one of the most promising precision-medicine directions in mesothelioma. Early 2025 trial results showed preliminary efficacy signals, and multiple Phase I/II studies are actively enrolling. For the patient subset carrying the mutation, this is a fundamentally different therapeutic approach than chemotherapy or immunotherapy.

Patient populationBAP1-mutant tumors (~60%)

Drug classesPARP · EZH2 · synthetic lethal

Testing requiredMolecular tumor profiling

Ph. I/II

Antibody-drug conjugate

TROP2-directed antibody-drug conjugates

Antibody-drug conjugates (ADCs) combine a targeting antibody with a cytotoxic "payload" — delivering chemotherapy directly to tumor cells while sparing healthy tissue. TROP2 (trophoblast cell surface antigen 2) is expressed on many mesothelioma tumors, and TROP2-directed ADCs are now in early-phase trials for mesothelioma after showing activity in lung and breast cancers. The approach represents a different lever than either immunotherapy or traditional chemotherapy.

MechanismTargeted chemotherapy delivery

StatusEarly-phase trials enrolling

Leading centersMSK, MD Anderson

Protocol

Light-based therapy

Photodynamic therapy (PDT) with surgery

Photodynamic therapy uses a light-activated drug (a photosensitizer) administered before surgery. During the operation, the tumor bed is illuminated with a specific wavelength of light, activating the drug and destroying any remaining cancer cells. Penn Medicine is the principal U.S. center offering this approach for pleural mesothelioma. Published outcomes from Penn's program have shown notable survival extensions in a subset of treated patients, though patient selection is critical and the technique remains technically demanding.

Leading centerPenn Medicine · Philadelphia

StageAvailable in specialized protocols

Best forSurgical candidates, pleural

Ph. II

Targeted immunotoxin

SS1P and next-generation mesothelin-targeted drugs

Beyond CAR-T, a second wave of mesothelin-targeted therapies is in development. SS1P, an immunotoxin combining an anti-mesothelin antibody with a bacterial toxin, demonstrated partial tumor response in 12 of 20 patients in early trials. Next-generation versions are designed to overcome the immunogenicity limitations that restricted the original SS1P. These approaches target the same protein CAR-T cells recognize, but via a fundamentally different delivery mechanism.

TargetMesothelin

MechanismAntibody-linked toxin

Development stagePhase II with improved variants

Approved +

Bioelectric therapy

Advanced Tumor Treating Fields (TTFields) protocols

TTFields (marketed as Optune Lua for mesothelioma) use low-intensity, alternating electric fields at 150 kHz to disrupt cancer cell division. The approach is already FDA-approved in combination with chemotherapy for pleural mesothelioma, based on the STELLAR trial, which showed a median overall survival of 18.2 months with TTFields + chemotherapy. Next-generation research is exploring TTFields in combination with immunotherapy, in post-surgical consolidation, and for peritoneal mesothelioma.

Current approvalPleural, with chemo

Next-gen studies+ immunotherapy, peritoneal

Delivered viaWearable device

Ph. III

Immunotherapy combos

Next-generation immunotherapy combinations

Even as Opdivo + Yervoy and Keytruda + chemotherapy reshape first-line treatment, research is racing ahead to the next generation of combinations — dual-targeting molecules like MEDI5752 (a bispecific antibody blocking both PD-1 and CTLA-4), novel checkpoint inhibitors beyond PD-1 and CTLA-4, and combinations that pair immunotherapy with TTFields or with emerging cell-based therapies. For patients whose disease progresses on current standards of care, these trial-based combinations represent the most meaningful next-line options.

ExamplesMEDI5752 + chemotherapy

Testing strategyBispecific checkpoint blockade

Trial accessNCI-designated centers

Accessing these therapies

How to find and enroll in a clinical trial.

The path from "I want to know what's available" to "I'm enrolled" is more navigable than it looks — especially with the help of a specialist center or patient advocate. Here's the short version.

Search the NCI database.

The National Cancer Institute maintains a searchable database of active mesothelioma trials at cancer.gov. ClinicalTrials.gov is the broader government registry. Both are free to use and filterable by location, phase, and eligibility.

Consult at a specialty center.

The highest-impact step is a consultation at one of the major mesothelioma programs. Their physicians run the trials, know the eligibility criteria by heart, and can often match a patient to an appropriate protocol within a single visit.

Let an advocate coordinate.

Patient advocates specializing in mesothelioma regularly navigate trial logistics — identifying candidate trials, coordinating second opinions, and handling travel. For many families, this alone materially shortens the time to treatment.

Interested in trial options?

A patient advocate can review your situation and connect you with specialists running relevant trials — a conversation that can open up options well beyond the standard of care.

Start the conversation