A landmark clinical trial that reshaped treatment for mesothelioma continues to show strong results years later. A five-year follow-up analysis of the CheckMate-743 study confirms that immunotherapy remains more effective than traditional chemotherapy in extending survival for patients with unresectable pleural mesothelioma, an aggressive cancer that forms in the lining of the lungs.
The findings, published in the Journal of Clinical Oncology, reinforce the growing role of immunotherapy as a frontline treatment option for this rare and fast-progressing disease. The results also highlight how a combination of two immunotherapy drugs—Opdivo (nivolumab) and Yervoy (ipilimumab)—can significantly improve long-term survival compared with chemotherapy alone.
Five-Year Survival Rate More Than Doubles With Immunotherapy
The follow-up study analyzed outcomes from 605 patients diagnosed with unresectable pleural mesothelioma. Because surgery was not an option for these patients, chemotherapy had long been considered the standard treatment approach.
Participants in the trial were divided into two groups. One group received the immunotherapy combination of Opdivo and Yervoy, while the other group was treated with conventional chemotherapy.
Initial findings from the CheckMate-743 trial already suggested that immunotherapy could provide a survival advantage. Patients receiving Opdivo and Yervoy experienced a median survival of 18.1 months, compared with 14.1 months for those treated with chemotherapy.
Five years later, the updated analysis confirms that the survival gap has persisted—and even widened.
The immunotherapy combination achieved a five-year survival rate of 14 percent. In practical terms, this means that 14 percent of patients treated with Opdivo and Yervoy were still alive at least five years after starting therapy.
By contrast, only 6 percent of patients who received chemotherapy reached the five-year mark. Historically, the overall five-year survival rate for mesothelioma patients across all treatments has hovered around 7 to 8 percent.
Immunotherapy Leads Across Every Survival Milestone
Throughout the duration of the study, immunotherapy consistently delivered higher survival rates than chemotherapy at each measured interval.
After one year, 68 percent of patients receiving Opdivo and Yervoy were still alive, compared with 58 percent in the chemotherapy group. The difference continued to grow over time.
Two-year survival rates were 41 percent for the immunotherapy group and 27 percent for chemotherapy. At the three-year mark, survival stood at 23 percent for patients treated with Opdivo and Yervoy, compared with 15 percent for chemotherapy.
Four-year survival rates were 17 percent for the immunotherapy group and 11 percent for those who received chemotherapy.
The steady advantage across all time points strengthens the argument that immune-based treatments can deliver more durable responses for patients with mesothelioma.
Most Participants Had Advanced Disease
Another important aspect of the CheckMate-743 trial is that most participants were diagnosed at an advanced stage of mesothelioma. The majority of patients had stage 3 or stage 4 disease, when tumors have spread extensively and treatment options are limited.
At these stages, surgery is rarely possible. For years, chemotherapy has been the primary treatment used to slow disease progression and provide modest survival benefits, often extending life by only a few months.
The strong performance of Opdivo and Yervoy in this high-risk population suggests that immunotherapy may offer meaningful long-term benefits even for patients with late-stage mesothelioma.
For many patients facing advanced disease, the possibility of living several years with treatment represents a significant improvement compared with historical outcomes.
Strong Results in Hard-to-Treat Sarcomatoid Mesothelioma
The study also revealed particularly promising outcomes for patients with sarcomatoid mesothelioma, a rare and aggressive subtype that is typically more difficult to treat.
Mesothelioma tumors are generally classified by cell type. Sarcomatoid cells tend to spread quickly and are harder to detect through imaging and biopsy. As a result, patients with this subtype often have poorer survival outcomes compared with those with epithelioid mesothelioma, which is considered more manageable.
In the CheckMate-743 trial, the immunotherapy combination delivered a five-year survival rate of 12 percent among patients with sarcomatoid mesothelioma. By comparison, only 1 percent of patients with the same subtype survived five years when treated with chemotherapy alone.
The results demonstrate that immunotherapy may be particularly beneficial for patients with this aggressive cell type, offering survival improvements that were previously difficult to achieve.
For patients with epithelioid mesothelioma, outcomes were also better with immunotherapy. Five-year survival reached 14 percent in the Opdivo-Yervoy group, compared with 8 percent for chemotherapy.
How Opdivo and Yervoy Work
Both Opdivo and Yervoy belong to a class of cancer treatments known as immune checkpoint inhibitors. These therapies work by helping the body’s immune system recognize and attack cancer cells.
Under normal conditions, certain proteins on the surface of cancer cells interact with proteins on immune cells to suppress the immune response. This interaction essentially allows cancer cells to hide from the immune system.
Checkpoint inhibitors block these protein connections. When the interaction is disrupted, immune cells can identify the cancer as a threat and launch an attack against the tumor.
By restoring the immune system’s ability to recognize cancer cells, these therapies can trigger longer-lasting responses compared with many traditional treatments.
Regulatory Approval and Expanding Treatment Options
Following the original publication of the CheckMate-743 results, the U.S. Food and Drug Administration (FDA) approved the use of Opdivo and Yervoy as a treatment option for patients with unresectable pleural mesothelioma.
The approval marked a significant milestone for the disease, introducing immunotherapy as a standard approach alongside chemotherapy for patients who are not eligible for surgery.
Since then, additional immunotherapy options have also entered the treatment landscape. Keytruda (pembrolizumab), another checkpoint inhibitor, has received FDA approval for pleural mesothelioma as well, expanding the range of immune-based therapies available to patients.
A Turning Point in Mesothelioma Treatment
For decades, mesothelioma treatment options remained limited, with chemotherapy serving as the primary therapy for advanced disease. The long-term data from CheckMate-743 signals a major shift in that paradigm.
By demonstrating durable survival improvements, the study supports the growing role of immunotherapy as a core component of mesothelioma care.
While researchers continue to explore new treatment combinations and targeted therapies, the five-year follow-up results confirm that immune checkpoint inhibitors have already begun to transform outcomes for patients facing this challenging cancer.
