Dual-Target Immunotherapy Shows 52% Response

A New Contender in Mesothelioma Treatment

The immunotherapy landscape for mesothelioma may be shifting again. At the 2025 ASCO Annual Meeting, BioNTech presented Phase 2 data showing that its experimental drug BNT327, combined with chemotherapy, produced tumor shrinkage in more than half of previously untreated patients — a response rate that rivals or potentially exceeds currently approved immunotherapies.

The results are preliminary, drawn from just 31 patients in a single-arm Chinese trial. But the numbers have caught the attention of researchers who have seen few new options emerge for this difficult-to-treat cancer.

How BNT327 Works

Most mesothelioma immunotherapies target a single pathway. BNT327 takes a different approach.

The drug is a bispecific antibody — a molecule engineered to bind two different targets simultaneously. One arm blocks PD-L1, an immune checkpoint that tumors exploit to hide from the immune system. The other arm blocks VEGF-A, a protein that tumors use to grow new blood vessels and secure their nutrient supply.

By hitting both targets with one drug, the theory goes, BNT327 attacks mesothelioma on two fronts: unleashing the immune system while cutting off the tumor’s lifeline.

The Numbers

Of 31 patients who received BNT327 plus standard chemotherapy, 16 saw their tumors shrink significantly — an overall response rate of 51.6%. One patient achieved a complete response, meaning no detectable cancer remained on imaging. Another 12 patients had stable disease, meaning their cancer stopped growing.

Add those together, and 90.3% of patients achieved disease control — a striking figure in a cancer where progression often comes quickly.

Perhaps most intriguing were the results in peritoneal mesothelioma, a subtype with no specifically approved treatments. Among six peritoneal patients in the trial, five responded to treatment — an 83.3% response rate — and all six achieved disease control. Their median progression-free survival reached 19.5 months.

How It Compares

Cross-trial comparisons are imperfect; different patient populations and study designs make direct head-to-head conclusions unreliable. With that caveat, the BNT327 data looks competitive with approved options.

The FDA-approved combination of Opdivo plus Yervoy produces response rates around 40% and disease control around 77% in first-line pleural mesothelioma. Chemotherapy alone yields similar numbers. BNT327’s 52% response rate and 90% disease control appear to improve on both — though a randomized comparison would be needed to know for certain.

Safety Concerns

The treatment wasn’t easy on patients. Nearly all — 93.5% — experienced serious side effects of Grade 3 or higher, primarily blood-related toxicities from the chemotherapy component. Decreased neutrophils and white blood cells were common, as were anemia and low platelet counts.

Five patients, about 16%, discontinued treatment due to side effects. But there were no treatment-related deaths, and the rate of immune-related adverse events was relatively low compared to some immunotherapy combinations.

The safety profile largely reflects the chemotherapy backbone rather than the novel drug itself. Whether BNT327’s dual targeting mechanism introduces unique long-term concerns remains unclear.

The Long Road Ahead

Promising Phase 2 data doesn’t guarantee a new treatment option. BioNTech has acknowledged that mesothelioma, while on its development plan, isn’t the company’s top priority. The drug is advancing more rapidly in lung cancer and triple-negative breast cancer, where larger patient populations make trials faster to complete.

A Phase 3 trial in mesothelioma — the kind of large, randomized study needed for FDA approval — has no announced timeline. Patients hoping to access BNT327 would need to find and enroll in clinical trials, which may be limited geographically.

What Patients Should Know

BNT327 isn’t available outside of clinical trials, and those trials are currently running in China rather than the United States. For patients seeking treatment now, existing options remain the best path forward.

The FDA-approved combination of Opdivo plus Yervoy represents the current standard of care in first-line treatment for appropriate candidates. Chemotherapy continues to play a role, particularly in combination regimens. For patients whose disease has progressed on initial treatment, emerging options like VT3989 are under investigation.

The BNT327 results offer reason for cautious optimism. A drug that can achieve disease control in 90% of patients would represent meaningful progress. But mesothelioma patients have seen promising early data before — and learned to wait for the larger studies that separate hope from reality.