The Mesothelioma Treatment Landscape in 2026

The mesothelioma treatment landscape has changed more in the past six years than in the previous thirty. The 2020 FDA approval of nivolumab plus ipilimumab ended 16 years without a new first-line option. In 2024, pembrolizumab plus chemotherapy became the second approved first-line immunotherapy regimen. The 2026 five-year update to the CheckMate-743 trial confirmed the durability of dual checkpoint benefit. A new generation of bispecific antibodies, cell therapies, and targeted drugs is moving through Phase 2 and Phase 3 trials.

This is the full picture of what is approved, what is promising, and what is still coming.

Approved First-Line Treatments

Nivolumab Plus Ipilimumab

The CheckMate-743 trial changed the standard of care when initial results were published in Baas et al., The Lancet 2021 (median OS 18.1 months on nivolumab plus ipilimumab versus 14.1 months on chemotherapy). The 2026 update, published in the Journal of Clinical Oncology (Scherpereel et al., DOI 10.1200/JCO-25-01328) at a median follow-up of 66.8 months, confirmed and extended those findings. At five years:

• 14% of patients on the immunotherapy combination were alive, compared to 6% on chemotherapy (HR 0.74, 95% CI 0.62 to 0.88)
• 17% of patients who initially responded to immunotherapy maintained their response at five years; 0% of chemotherapy responders did
• In non-epithelioid disease, where chemotherapy has historically been least effective, 5-year survival was 12% on immunotherapy versus 1% on chemotherapy

The 5-year paper also reported an exploratory biomarker signal. Patients with high baseline levels of monocytic myeloid-derived suppressor cells (M-MDSCs) had worse overall outcomes (HR 1.25, 95% CI 1.09 to 1.43) but still benefited from nivolumab plus ipilimumab over chemotherapy.

Pembrolizumab Plus Chemotherapy

The FDA approved pembrolizumab plus pemetrexed and platinum chemotherapy for unresectable advanced or metastatic pleural mesothelioma on September 17, 2024. Approval was based on the IND-227/KEYNOTE-483 Phase 3 trial (N=440), which reported median overall survival of 17.3 months on the combination versus 16.1 months on chemotherapy alone (HR 0.79, 95% CI 0.64 to 0.98, p=0.0324).

Chemotherapy

Pemetrexed (Alimta) combined with cisplatin was approved for pleural mesothelioma on February 4, 2004 based on the EMPHACIS trial (Vogelzang et al., JCO 2003). Median overall survival was 12.1 months versus 9.3 months for cisplatin alone, or 13.3 versus 10.0 months in the fully vitamin-supplemented arm (HR 0.77, p=0.021). The regimen remains the standard alternative for patients who cannot tolerate immunotherapy or who are ineligible for clinical trials, and it is the backbone for newer combinations.

Surgical Treatment

Surgery remains an important treatment option for mesothelioma in patients who qualify. The MARS 2 trial (Lim et al., The Lancet Respiratory Medicine, May 2024) compared extended pleurectomy decortication plus chemotherapy against chemotherapy alone in patients with resectable pleural mesothelioma. Extended pleurectomy decortication plus chemotherapy was associated with 28% higher mortality in the first 42 months (p=0.03), shorter median overall survival, more serious adverse events, and worse quality of life than chemotherapy alone. MARS 2 did not study extrapleural pneumonectomy.

For peritoneal mesothelioma, cytoreductive surgery combined with heated intraperitoneal chemotherapy (HIPEC) produces the best long-term outcomes of any mesothelioma treatment. A large single-center series from Inova (111 patients, 1993 to 2021) reported median overall survival of 39.6 months, rising to 67.7 months in patients who underwent repeat CRS-HIPEC. Published 5-year survival estimates for peritoneal mesothelioma with CRS/HIPEC range from 47% to 65% at high-volume centers.

Investigational and Emerging Treatments

BNT327 (PM8002)

One of the most watched drugs in the mesothelioma pipeline is BNT327, a bispecific antibody that simultaneously blocks PD-L1 (an immune checkpoint) and VEGF-A (a protein tumors use to grow blood vessels). A Phase 2 study (ASCO 2025 abstract) evaluated BNT327 in combination with chemotherapy as a first-line regimen in 31 previously untreated patients. Reported results:

• 52% overall response rate and 90% disease control rate across the 31-patient cohort
• 16.6-month median progression-free survival
• Peritoneal subgroup: 75% response rate and 100% disease control rate
• Pleural subgroup (n=23): 44% response rate and 15.8-month median progression-free survival
• 94% grade 3 or 4 treatment-related adverse events (mostly neutropenia), 19% discontinuations, no grade 5 events

These numbers come from a single-arm Phase 2 of BNT327 plus chemotherapy. The historical CheckMate-743 figures (18.1-month median OS, 6.8-month median PFS) reflect a different regimen (nivolumab plus ipilimumab, no chemo) and a different trial population, so any cross-trial comparison should be read with caution.

A 2026 preclinical study helped explain why dual-mechanism drugs may be particularly relevant in peritoneal disease, where single-agent checkpoint therapy has historically performed poorly.

BNT327 is not FDA approved. The Phase 2 trial is running primarily in China (NCT06712316), and no Phase 3 has been announced for mesothelioma. Patients interested in BNT327 should discuss trial eligibility with their oncologist.

Durvalumab

Durvalumab, a PD-L1 inhibitor, produced a median overall survival of 20.4 months in the PrE0505 Phase 2 trial (55 patients, Forde et al., 2021; historical chemotherapy comparator 12.1 months). The Phase 3 DREAM3R trial (NCT04334759) is comparing durvalumab plus chemotherapy against chemotherapy alone and nivolumab plus ipilimumab. Early survival results presented at ESMO 2025 were not yet statistically significant, with translational analyses reported at AACR 2026.

ADI-PEG20

ADI-PEG20 takes a metabolic approach. About half of mesothelioma tumors cannot make their own arginine, an amino acid essential for growth. ADI-PEG20 (pegargiminase) depletes arginine from the bloodstream. The Phase 3 ATOMIC-Meso trial (Szlosarek et al., JAMA Oncology 2024) in non-epithelioid pleural mesothelioma reported median progression-free survival of 6.2 months on ADI-PEG20 plus pemetrexed and cisplatin versus 5.6 months on placebo plus chemotherapy (HR 0.65, 95% CI 0.46 to 0.90, p=0.02).

VT3989 and TEAD Inhibitors

The YAP/TEAD signaling pathway is hyperactive in roughly half of mesothelioma cases, driven by loss of the NF2 tumor suppressor gene. VT3989 (Vivace Therapeutics) is a first-in-class oral TEAD autopalmitoylation inhibitor. At the optimized Phase 3 dose and schedule in mesothelioma, the ESMO 2025 dataset reported a 32% objective response rate (7 of 22), 86% disease control rate, and median progression-free survival of about 40 weeks. The drug has FDA Orphan Drug and Fast Track designations for mesothelioma, with a registrational Phase 3 planned.

TTFields (Optune Lua)

Tumor-treating fields, delivered by the Optune Lua (NovoTTF-100L) device, received FDA Humanitarian Device Exemption approval on May 23, 2019 for unresectable locally advanced or metastatic pleural mesothelioma, in combination with pemetrexed and platinum chemotherapy. The STELLAR trial (80 patients) reported median overall survival of 18.2 months with TTFields plus chemotherapy versus 12.1 months in a historical chemotherapy control.

Mesothelin CAR-T and Cell Therapies

Two active Phase 1 trials are testing engineered T cells against mesothelin, a protein expressed on nearly all mesothelioma cells: an intrapleural mesothelin CAR-T program at Memorial Sloan Kettering (NCT04577326) and a membrane-proximal mesothelin construct at the NCI (NCT06885697). Neither has reported a 2025 or 2026 topline. The approach remains investigational.

Treatment by Subtype

Treatment decisions depend on the type of mesothelioma and overall health.

Epithelioid pleural mesothelioma has the best prognosis and the most options. First-line nivolumab plus ipilimumab is a standard regimen, pembrolizumab plus chemotherapy is a second approved first-line option, and pleurectomy/decortication plus systemic therapy is considered at specialized centers for early-stage disease.

Non-epithelioid pleural mesothelioma (sarcomatoid or biphasic) responds less well to chemotherapy but shows a larger immunotherapy benefit. The 2026 CheckMate-743 update reported 12% 5-year survival on immunotherapy versus 1% on chemotherapy in this subgroup. ADI-PEG20 plus chemotherapy also improved progression-free survival specifically in non-epithelioid disease in ATOMIC-Meso.

Peritoneal mesothelioma is treated primarily with cytoreductive surgery plus HIPEC when operable. No immunotherapy is specifically approved for peritoneal disease, and the major Phase 3 immunotherapy trials have excluded peritoneal patients. For unresectable peritoneal disease, clinical trial enrollment is often the path to systemic options.

Recurrent or refractory mesothelioma has fewer established options. In the CONFIRM trial (Fennell et al., Lancet Oncology 2021), second-line nivolumab extended median overall survival to 9.2 months versus 6.6 months on placebo in relapsed pleural mesothelioma (HR 0.72, p=0.018), with benefit concentrated in epithelioid disease.

What Is Still Missing

Despite the progress, gaps remain.

Response rates to first-line immunotherapy still plateau well below universal benefit. More than half of patients do not respond to the best available treatments, and durable long-term responses are the exception.

No immunotherapy has been specifically approved for peritoneal mesothelioma. The major Phase 3 trials (CheckMate-743, PrE0505, DREAM3R) have been conducted in pleural disease.

Biomarkers that reliably predict response to therapy have not emerged. PD-L1, commonly used in other cancers, shows weak correlation with outcomes in mesothelioma. The CheckMate-743 M-MDSC signal is promising but needs prospective validation.

Access to clinical trials is uneven. Many people are treated outside of mesothelioma centers and never learn about investigational options. Programs in Illinois and other high-volume states host a disproportionate share of active trial sites.

The Next Twelve Months

Two near-term developments are worth watching.

DREAM3R continues to mature. If durvalumab plus chemotherapy ultimately replicates its Phase 2 survival benefit in the Phase 3 readout, the FDA could have a third first-line immunotherapy regimen to review.

BNT327 has no announced Phase 3 trial for mesothelioma. BioNTech entered a global partnership with BMS in June 2025 focused primarily on triple-negative breast cancer, and the 31-patient mesothelioma Phase 2 dataset is the current state of the evidence. Additional development for mesothelioma would likely require a larger, controlled study.