CheckMate-743 at Five Years: 14% Still Alive
Five-year data from CheckMate-743 shows 14% survival with nivolumab plus ipilimumab vs 6% with chemotherapy. Non-epithelioid benefit is striking.
Five years of follow-up data from the CheckMate-743 trial confirm that nivolumab plus ipilimumab provides a durable survival advantage over chemotherapy for people with unresectable pleural mesothelioma. The results, published today in the Journal of Clinical Oncology, show that 14% of people treated with the immunotherapy combination were alive at five years, compared to 6% of those treated with chemotherapy.
The updated analysis, based on a median follow-up of 66.8 months across 605 people, reinforces the original trial findings that led to FDA approval in October 2020.
Five-Year Survival Data
| Outcome | Immunotherapy | Chemotherapy |
|---|---|---|
| Five-year overall survival | 14% | 6% |
| Five-year progression-free survival | 8% | 0% |
| Objective response rate | 39% | 44% |
| Ongoing responses at five years | 17% | 0% |
The hazard ratio for overall survival was 0.74 (95% CI, 0.62 to 0.88), consistent with the 26% relative reduction in death risk reported in earlier analyses. Notably, none of the people who responded to chemotherapy still had ongoing responses at five years, while 17% of immunotherapy responders did.
Non-Epithelioid Results Are Striking
The most compelling finding continues to be in non-epithelioid mesothelioma (sarcomatoid and biphasic subtypes), where chemotherapy has historically offered limited benefit.
| Subtype | Immunotherapy 5-Year OS | Chemotherapy 5-Year OS | Hazard Ratio |
|---|---|---|---|
| Epithelioid | 14% | 8% | 0.85 |
| Non-epithelioid | 12% | 1% | 0.48 |
For people with non-epithelioid disease, the immunotherapy combination reduced the risk of death by 52% compared to chemotherapy. At five years, 12% of these people were alive, versus just 1% on chemotherapy.
Non-epithelioid mesothelioma accounts for roughly 20% to 25% of cases and historically carries a worse prognosis. The CheckMate-743 five-year data suggests immunotherapy has fundamentally changed outcomes for this subgroup.
Crossover and Adjusted Analysis
Approximately 24% of people in the chemotherapy arm received subsequent immunotherapy after disease progression, compared to 6% who crossed over in the immunotherapy arm. When adjusted for this treatment switching, the chemotherapy arm’s median overall survival drops from 14.1 months to 12.1 months, and the adjusted hazard ratio improves to 0.64 (95% CI, 0.53 to 0.78).
Biomarker Findings
The study also evaluated monocytic myeloid-derived suppressor cells (M-MDSC) as a potential biomarker. In the evaluable population, higher baseline M-MDSC levels were associated with worse outcomes on immunotherapy (HR 1.25 per log increase), suggesting these cells may play a role in resistance to dual checkpoint blockade. This finding could help identify which people are most likely to benefit from the combination.
What This Means for People with Mesothelioma
CheckMate-743 remains the landmark trial that changed first-line treatment for pleural mesothelioma. The five-year data confirms that immunotherapy offers something chemotherapy could not: durable, lasting responses for a meaningful number of people.
For people newly diagnosed with unresectable pleural mesothelioma, these numbers frame the conversation with their oncologist. A 14% chance of being alive at five years with immunotherapy, compared to 6% with chemotherapy, is a meaningful difference in a disease with historically poor outcomes.
No new safety signals were identified at five years. The long-term safety profile remained consistent with earlier reports.
References
Journal of Clinical Oncology. (2026-02-26). Five-Year Outcomes From CheckMate 743: Nivolumab Plus Ipilimumab vs Chemotherapy in Unresectable Malignant Pleural Mesothelioma.
https://ascopubs.org/doi/10.1200/JCO-25-01328
OncDaily. (2026-02-26). CheckMate 743: 5-Year Survival Data.
https://oncodaily.com/new-paper-alert/checkmate-743-5-year-survival
Reader Q&A
Frequently Asked Questions
What is CheckMate-743?
CheckMate-743 is a Phase 3 clinical trial that compared the immunotherapy combination of nivolumab (Opdivo) plus ipilimumab (Yervoy) against standard chemotherapy in 605 people with previously untreated, unresectable malignant pleural mesothelioma. Based on the initial results, the FDA approved this combination in October 2020.
How does the five-year data compare to the original results?
The original data showed a three-year survival rate of 23% with immunotherapy versus 15% with chemotherapy. At five years, the rates are 14% versus 6%. The survival benefit has held steady, and 17% of people who responded to immunotherapy still had ongoing responses at the five-year mark. No chemotherapy responders maintained their response that long.
Who benefits most from this combination?
People with non-epithelioid mesothelioma (sarcomatoid or biphasic subtypes) showed the largest benefit, with a 52% reduction in death risk. However, the combination also demonstrated meaningful benefit in epithelioid disease, the most common subtype.
Is this treatment currently available?
Yes. Nivolumab plus ipilimumab has been FDA-approved as first-line treatment for unresectable malignant pleural mesothelioma since October 2020. It is administered intravenously at cancer centers. A subcutaneous formulation of nivolumab (Opdivo Qvantig) was also recently approved, reducing infusion time.
What is the life expectancy of someone with immunotherapy for mesothelioma?
People with mesothelioma treated with immunotherapy, such as Opdivo plus Yervoy, have a median survival of 18.1 months, compared to 14.1 months with chemotherapy alone, per the CheckMate 743 trial. Keytruda combined with chemotherapy yields a median survival of 17.3-19.8 months. The DREAM trial reported 20.4 months median overall survival with durvalumab plus chemotherapy, rising to 24.3 months for epithelioid pleural mesothelioma. Overall, 3-year survival rates reach 23-25% with these treatments.
How did Steve McQueen get mesothelioma?
Steve McQueen was exposed to asbestos through multiple occupational and military sources over several decades. His primary exposure occurred during his service in the U.S. Marine Corps from 1947 to 1950, when he worked aboard naval ships and in shipyards, including removing asbestos lagging from pipes at Camp Lejeune. After his military service, he encountered additional asbestos exposure on movie soundstages where insulation contained the mineral, while wearing flame-resistant racing suits made with asbestos, and while working on race car and motorcycle brakes. McQueen did not develop symptoms until 1978, nearly 30 years after his initial military exposure, reflecting the typical latency period of 20 to 50 years between asbestos exposure and mesothelioma diagnosis. He was diagnosed with pleural mesothelioma in December 1979 and died in November 1980 at age 50.
How long can you be on nivolumab?
Nivolumab treatment duration varies by cancer type and clinical context, with many trials capping it at up to 2 years for advanced non-small-cell lung cancer (NSCLC) and melanoma in responders or those with stable disease. In a real-world French cohort of 259 pretreated advanced NSCLC cases, 25% were long-term survivors (≥2 years post-start), including 11 who continued beyond 2 years and showed higher 3-year overall survival rates (100%) compared to those stopping at or before 2 years (49-85.7%). Some studies administered nivolumab until progression or toxicity, while others like CheckMate-153 suggested benefits from continuation beyond 1 year, though optimal duration remains unestablished without prospective randomized data. Nivolumab persists in the body for at least 3-4 months after the last dose.
Does immunotherapy work for pleural mesothelioma?
Immunotherapy works for unresectable pleural mesothelioma, with FDA-approved options including nivolumab plus ipilimumab (Opdivo and Yervoy) as first-line treatment based on the CheckMate 743 trial, which showed median overall survival of 18.1 months versus 14.1 months with chemotherapy alone. Pembrolizumab (Keytruda) combined with pemetrexed and platinum chemotherapy is also FDA-approved following the KEYNOTE-483 trial, improving overall survival to 17.3 months from 16.1 months with chemotherapy. These immune checkpoint inhibitors demonstrate particular effectiveness in non-epithelioid subtypes, extending survival and controlling disease in people with pleural mesothelioma. Ongoing trials like BEAT-meso explore further combinations.