Immunotherapy for mesothelioma shows durable benefits
Summary points
Table of Contents
- At five years, 14 percent of patients treated with the immunotherapy combination were still alive, compared with 6 percent of those who received chemotherapy.
- In patients with epithelioid mesothelioma, the five-year overall survival rate was 14 percent with immunotherapy versus 8 percent with chemotherapy.
- In patients with non-epithelioid disease, which is typically more aggressive, five-year survival was 12 percent with immunotherapy compared with just 1 percent.
- Median overall survival was 18.1 months for patients who received nivolumab plus ipilimumab, compared with 14.1 months for those treated with chemotherapy.
- About 39 percent of patients responded to nivolumab plus ipilimumab, compared with 44 percent on chemotherapy.
- Among patients who responded to immunotherapy, 17 percent still had an ongoing response at five years.
Checkmate 743 Study 5-Year Follow-Up Results
A new five-year update from the pivotal CheckMate 743 study offers encouraging news for patients facing unresectable pleural mesothelioma, a rare and aggressive cancer associated with asbestos exposure. The findings, recently highlighted by OncoDaily and published in the Journal of Clinical Oncology, show that a two-drug immunotherapy combination continues to help some patients live significantly longer than standard chemotherapy alone.
The study compared nivolumab plus ipilimumab (also known as Yervoy and Opdivo), two immune checkpoint inhibitor drugs, with traditional platinum-based chemotherapy (Alimta plus cis or carboplatin) as first line treatment. Researchers followed patients for a median of nearly 67 months, making this the longest follow up to date for first line immunotherapy in pleural mesothelioma.
According to the journal article, “nivolumab plus ipilimumab demonstrated continued overall survival benefit versus chemotherapy in all randomly assigned patients.” At five years, 14 percent of patients treated with the immunotherapy combination were still alive, compared with 6 percent of those who received chemotherapy. The hazard ratio for overall survival was 0.74, meaning the risk of death was reduced by about 26 percent with immunotherapy compared with chemotherapy.
In patients with epithelioid mesothelioma, the five-year overall survival rate was 14 percent with immunotherapy versus 8 percent with chemotherapy. In patients with nonepithelioid disease, which is typically more aggressive, the difference was even more striking. Five-year survival was 12 percent with immunotherapy compared with just 1 percent with chemotherapy. The hazard ratio in this group was 0.48, suggesting a substantially lower risk of death with the immunotherapy combination.
Median overall survival was 18.1 months for patients who received nivolumab plus ipilimumab, compared with 14.1 months for those treated with chemotherapy. While those numbers may seem modest, mesothelioma has historically been extremely difficult to treat, and long-term survival has been rare. The five-year survival rate of 14 percent in the immunotherapy group stands out in a disease where durable responses have been uncommon. Moreover, data expressed as “median” needs to be understood as not an average, rather the notion that half of the patients lived longer than the median, and some substantially longer.
Response rates were similar between the two groups at the start. About 39 percent of patients responded to nivolumab plus ipilimumab, compared with 44 percent on chemotherapy. However, the durability of those responses differed. Among patients who responded to immunotherapy, 17 percent still had an ongoing response at five years. In the chemotherapy group, none of the responders had an ongoing response at that time point. This pattern supports the idea that while chemotherapy may shrink tumors quickly, immunotherapy may offer longer lasting control in a subset of patients.
Identifying Respondents’ Biomarkers to Better Screen Patients Who Benefit from Immunotherapy
The researchers also explored whether certain blood-based markers might predict who benefits most. They looked at levels of monocytic myeloid derived suppressor cells, known as M-MDSCs. These cells are thought to suppress the immune system and may interfere with immunotherapy. In patients treated with nivolumab plus ipilimumab, higher baseline M-MDSC levels were associated with worse overall survival. The hazard ratio for overall survival was 1.25 for patients with higher levels compared with lower levels. The authors noted that these findings are exploratory and that more research is needed to confirm whether M-MDSC levels could help guide treatment decisions in the future.
Another important question was whether the results might be influenced by patients who crossed over to immunotherapy after starting on chemotherapy. In the study, 24 percent of patients in the chemotherapy arm later received immunotherapy. To account for this, the researchers performed an adjusted analysis. After adjusting for treatment switching, the hazard ratio for overall survival improved to 0.64 in favor of nivolumab plus ipilimumab. Median overall survival in the chemotherapy group dropped to 12.1 months after adjustment, which further highlighted the benefit of starting immunotherapy first.
Safety findings were consistent with earlier reports. The authors stated that “no new safety signals were observed” with longer follow up. This suggests that the known side effects of nivolumab plus ipilimumab remain manageable over time, though immune related side effects can still be serious and require careful monitoring.
In their conclusion, the investigators wrote that this five-year update demonstrated continued long term, durable clinical benefit of first line nivolumab plus ipilimumab in patients with pleural mesothelioma, regardless of tumor histology. They added that the results further support first line nivolumab plus ipilimumab as standard of care for unresectable pleural mesothelioma.
The coverage by OncoDaily described the findings as reinforcing the long-term value of the combination immunotherapy and emphasized that this is the longest follow up yet for first line immunotherapy in pleural mesothelioma.
For patients and families facing this diagnosis, these results do not represent a cure. However, they do mark a meaningful step forward. A treatment approach that can help a portion of patients live five years or longer, particularly in a cancer long associated with limited options, reflects real progress. Ongoing research will continue to refine who benefits most and how to build on these gains.
Related Posts
A study into the experience of caregivers yields first findings
January 13, 2026
