Unresectable malignant pleural mesothelioma (MPM) has historically been treated with platinum/pemetrexed chemotherapy. The randomized phase 3 CheckMate 743 trial introduced a chemotherapy-sparing option—nivolumab plus ipilimumab—that became an important first-line option for selected fit patients. This narrative review synthesizes pivotal and real-world evidence to compare these approaches and offers an evidence-based framework for regimen selection in US/EU practice.
Pivotal efficacy evidence
CheckMate 743 trial design and population. CheckMate 743 was an open-label, randomized phase 3 study at 103 centers in 21 countries enrolling 605 adults with previously untreated, unresectable MPM and ECOG performance status (PS) 0–1, stratified by histology (epithelioid vs non-epithelioid) and sex. Patients were randomized to nivolumab 3 mg/kg IV every 2 weeks plus ipilimumab 1 mg/kg IV every 6 weeks (up to 2 years) versus platinum (cisplatin 75 mg/m² or carboplatin AUC 5, investigator’s choice) plus pemetrexed 500 mg/m² IV every 3 weeks for up to 6 cycles. Approximately 66% received carboplatin and 34% cisplatin, reflecting contemporary practice; median age was 69 years and 77% were male 1.
Primary endpoint—overall survival (OS). At the interim analysis (median follow-up 29.7 months), nivolumab plus ipilimumab significantly improved OS versus chemotherapy: median 18.1 months (95% CI 16.8–21.4) versus 14.1 months (95% CI 12.4–16.2); HR 0.74 (96.6% CI 0.60–0.91); p=0.0020. Two-year OS was 41% versus 27% 1. With prolonged follow-up (median 66.8 months), the 5-year OS rates were 14% versus 6%; HR 0.74 (95% CI 0.62–0.88). Adjustment for crossover to immunotherapy in the chemotherapy arm (24% received subsequent immunotherapy) further amplified the OS benefit (adjusted HR 0.64; 95% CI 0.53–0.78), reducing adjusted chemotherapy median OS to 12.1 months 21.
Secondary endpoints—progression-free survival (PFS), response, duration. Early PFS was similar (median 6.8 vs 7.2 months; HR 1.00, 95% CI 0.82–1.21), but tails emerged with time: 3-year PFS was 14% versus 1% 1. Objective response rates (ORR) were comparable (approximately 40% in both arms), yet duration of response favored immunotherapy (median 11.0 months vs 6.7 months); 17% of responders on nivolumab plus ipilimumab had ongoing responses at 5 years versus 0% on chemotherapy 21.
Histology-stratified findings. Benefit differed markedly by histology. In non-epithelioid (sarcomatoid/biphasic) disease, nivolumab plus ipilimumab yielded median OS 18.1 months versus 8.8 months with chemotherapy (HR 0.46, 95% CI 0.31–0.68), a dramatic absolute and relative benefit. In epithelioid disease, median OS was 18.2 versus 16.7 months; HR 0.85 (95% CI 0.69–1.04)—a modest, non–statistically significant trend. These patterns persisted with longer follow-up (5-year OS 12% vs 1% non-epithelioid; HR ~0.48; epithelioid HR ~0.85) 11421.
Safety. Grade 3–4 treatment-related adverse events (TRAEs) occurred in 30% with nivolumab plus ipilimumab versus 32% with chemotherapy; discontinuation due to toxicity was higher with immunotherapy (23% vs 16%). Treatment-related deaths occurred in 1% (pneumonitis, encephalitis, heart failure) with nivolumab plus ipilimumab and <1% (myelosuppression) with chemotherapy. Most irAEs resolved by database lock except endocrine events, which often require long-term hormone replacement 1. The US label reports serious adverse reactions in ~54%, fatal reactions in 1.3%, and dose delays in 52% on nivolumab plus ipilimumab; infusion reactions occurred in 12% 23.
Platinum/pemetrexed benchmark. The EMPHACIS phase 3 trial established cisplatin/pemetrexed as standard: median OS 12.1 months with cisplatin/pemetrexed versus 9.3 months with cisplatin alone (HR 0.77), with improved time to progression (5.7 vs 3.9 months) and response rates (41.3% vs 16.7%) 5. Real-world cohorts commonly report median OS 12–14 months with platinum/pemetrexed, with higher medians in selected populations 823.
Regulatory and guideline positions. The FDA (2020), EMA, and NICE endorse first-line nivolumab with ipilimumab for unresectable MPM; NCCN lists it as a preferred first-line option based on CheckMate 743, emphasizing larger benefit in non-epithelioid disease 142324. ESMO/NCCN guidance reiterates histology-dependent benefit and the need for careful patient selection by PS and comorbidity profile 25.
Histology-based treatment selection
Non-epithelioid disease. CheckMate 743 demonstrated a large, clinically meaningful benefit for sarcomatoid/biphasic subtypes (HR 0.46; ~9.3-month absolute OS advantage), consistent with the historical chemo-resistance and aggressive biology of non-epithelioid MPM. For fit patients (PS 0–1), nivolumab plus ipilimumab should be the clear preferred regimen 11421.
Epithelioid disease. In epithelioid MPM, nivolumab plus ipilimumab produced a modest OS improvement (~2 months; HR ~0.85, CI spanning 1.0). Given epithelioid disease’s better chemotherapy responsiveness, either regimen is acceptable. Long-term durability favors immunotherapy, while chemotherapy offers faster cytoreduction with predictable toxicity. A 2024 network meta-analysis suggested bevacizumab plus chemotherapy may yield the largest OS increase in epithelioid disease, whereas nivolumab plus ipilimumab best increases OS in non-epithelioid disease, though this indirect evidence requires clinical context 20.
Real-world evidence and external validity
Multiple real-world cohorts help calibrate expectations outside trial settings.
- France (Meso-Immune; n=201; median age 75; 92% PS 0–1; 74.5% epithelioid): median OS 18.9 months overall; epithelioid 21.0 months; non-epithelioid 14.1 months. Grade 3–4 AEs 23.3%; treatment-related deaths 1.5%—toxicity somewhat lower than CheckMate 743, possibly reflecting selection and vigilant management 2.
- Latin America (ImmunoMeso; n=96; 81% PS 0–1; 78% epithelioid): median OS 22 months; grade 3–4 AEs 18.5%; dose delays/discontinuations for irAEs did not impair OS 3.
- Switzerland (n=109; median age 72; 83% PS 0–1; 75% epithelioid): in first line (43% of cohort), median OS 12.6 months; any-grade TRAEs 62%; discontinuation for toxicity 22%. Outcomes were substantially worse in PS ≥2: median OS 2.4 vs 11.9 months (PS 0–1) 413.
- Germany (n=135; unselected; mean age 72): median OS 13.6 months overall; PS ≥2 median OS 3.5 months; age ≥75 years median OS 9.6 months versus 18.8 months in <65 years. Histology differences were smaller than in CheckMate 743 22.
Taken together, real-world results confirm effectiveness but consistently show lower median OS than the trial, largely attributable to older age, inclusion of PS ≥2, and broader comorbidity. Performance status and age are strong determinants of immunotherapy outcomes in practice 2341322.
Patient-factor and safety considerations
Performance status. CheckMate 743 enrolled only PS 0–1. Real-world cohorts demonstrate poor outcomes with nivolumab plus ipilimumab in PS ≥2 (median OS 2.4–3.5 months), suggesting frail patients are unlikely to benefit and may be harmed by toxicity. For PS ≥2, consider chemotherapy (in selected cases) or best supportive care 41322.
Age. Age alone is not a contraindication; trials included older adults. However, patients ≥75 years often fare worse with dual immunotherapy (median OS ~9.6 months in German cohort), likely reflecting comorbidity and frailty. Individualize decisions, weighing goals, reserve, and monitoring feasibility 22.
Autoimmune disease and baseline steroids. Active autoimmune disease or chronic immunosuppressive therapy were excluded from CheckMate 743. Dual checkpoint blockade increases risk of autoimmune flares and severe irAEs. In such patients, platinum/pemetrexed is generally preferred; exceptions require specialist input and close monitoring 125.
Organ function. Cisplatin/pemetrexed requires adequate renal function and marrow reserve. Pemetrexed is contraindicated if creatinine clearance <45 mL/min; cisplatin is often avoided below ~60 mL/min, with carboplatin substitution. Chemotherapy with pemetrexed requires folic acid supplementation (400–1000 mcg/day), vitamin B12 (1 mg IM approximately every 9 weeks), and dexamethasone premedication to reduce hematologic and gastrointestinal toxicity; without supplementation, severe neutropenia and febrile neutropenia are substantially higher 67. Nivolumab plus ipilimumab has no renal dose adjustment but requires careful hepatic and pulmonary monitoring due to risks of immune-mediated hepatitis and pneumonitis 123.
Toxicity profiles. Chemotherapy toxicities are predictable and dose-dependent (myelosuppression, nephrotoxicity, GI effects). In supplemented cohorts, grade 3–4 neutropenia ~23%, anemia 4–6%, thrombocytopenia 4–5%; renal failure occurred in ~2% in EMPHACIS 56. Immunotherapy toxicities are immune-related, can be multi-organ, delayed, and occasionally permanent (e.g., endocrine). In CheckMate 743, grade 3–4 TRAEs occurred in ~30%, discontinuation 23%, and rare treatment-related deaths (1%). Endocrine irAEs often require lifelong hormone replacement; pneumonitis, hepatitis, colitis, and myocarditis require prompt steroids and specialist co-management 1121823.
Practical irAE monitoring and management. Recommended practices include:
- Baseline: Thyroid function (TSH, free T4), liver enzymes, creatinine, glucose; clinical assessment; consider pulmonary and cardiac baselines in high-risk patients 126.
- During therapy: Clinical review every infusion; labs every 2–4 weeks (programs vary from every 2–3 weeks early to every 4–6 weeks per guideline) 126.
- Education: Urgent reporting of diarrhea, dyspnea/cough, jaundice, severe fatigue/orthostasis, headache, visual changes 11226.
- Management: Hold ICPis for most grade ≥2 toxicities; initiate prednisone 0.5–1 mg/kg/day for grade 2 and 1–2 mg/kg/day for grade 3; slow taper ≥4–6 weeks; resume when ≤grade 1. Grade 4 typically warrants permanent discontinuation (except controlled endocrinopathies). Use infliximab for steroid-refractory colitis; mycophenolate for hepatitis; involve specialists early 1121826.
Surgery context. The MARS 2 trial in resectable disease found worse survival and far more serious adverse events with extended pleurectomy decortication plus chemotherapy versus chemotherapy alone, reinforcing that systemic therapy drives outcomes and supporting non-surgical management for unresectable disease 11.
Comparative snapshot
Table 1. Efficacy, safety, and dosing highlights
| Feature | Nivolumab + ipilimumab | Platinum/pemetrexed chemotherapy |
|---|---|---|
| Regimen (trial/label) | Nivolumab 3 mg/kg q2w + ipilimumab 1 mg/kg q6w up to 2 years (trial); FDA label: nivolumab 360 mg q3w + ipilimumab 1 mg/kg q6w 123 | Pemetrexed 500 mg/m² + cisplatin 75 mg/m² q3w × up to 6 cycles; carboplatin AUC 5 acceptable alternative 16 |
| Primary OS (overall) | 18.1 vs 14.1 months; HR 0.74; 5-yr OS 14% vs 6% 121 | EMPHACIS: 12.1 vs 9.3 months (cisplatin alone); HR 0.77 5 |
| Histology—non-epithelioid | Median OS 18.1 vs 8.8 months; HR 0.46 114 | Poor outcomes historically; no histology-specific benefit 5 |
| Histology—epithelioid | Median OS 18.2 vs 16.7 months; HR 0.85 114 | Baseline standard; epithelioid relatively chemosensitive 5 |
| PFS and DOR | Median PFS similar; 3-yr PFS 14% vs 1%; longer DOR (11.0 vs 6.7 months) 121 | Shorter DOR; PFS benefits modest 5 |
| Grade 3–4 TRAEs | ~30%; discontinuation 23%; rare fatal irAEs 123 | Hematologic grade 3–4 (neutropenia ~23% with vitamins); renal failure ~2% 56 |
| Key eligibility issues | PS 0–1; caution in autoimmune disease; organ monitoring 1 | CrCl ≥45 mL/min; vitamin supplementation mandatory; marrow reserve required 67 |
Clinical recommendation framework
The choice between nivolumab plus ipilimumab and platinum/pemetrexed should be individualized by histology, PS, comorbidity, organ function, and patient preference.
Table 2. Scenario-based first-line selection
| Clinical scenario | Preferred option | Rationale |
|---|---|---|
| Non-epithelioid (sarcomatoid/biphasic), PS 0–1, no active autoimmune disease | Nivolumab + ipilimumab (strong preference) | Large OS benefit (HR 0.46; 9.3-month absolute gain) and durable responses; chemotherapy historically poor 114 |
| Epithelioid, PS 0–1, good organ function | Nivolumab + ipilimumab or platinum/pemetrexed (shared decision) | Modest OS advantage for immunotherapy with durable tail; chemotherapy offers faster cytoreduction and predictable toxicity; consider patient preference, logistics of irAE monitoring 114 |
| PS ≥2 or frail elderly (≥75 years) | Platinum/pemetrexed (selected) or best supportive care | Real-world OS with dual immunotherapy is poor (PS ≥2 ~2.4–3.5 months; ≥75 years ~9.6 months); toxicity burden may outweigh benefit 41322 |
| Active autoimmune disease or baseline systemic steroids | Platinum/pemetrexed | High risk of irAE exacerbation with dual ICPi; chemotherapy safer and predictable 125 |
| Renal impairment (CrCl 45–60 mL/min) | Carboplatin/pemetrexed or nivolumab + ipilimumab | Pemetrexed contraindicated if CrCl <45 mL/min; carboplatin acceptable; dual immunotherapy needs no renal adjustment but careful irAE monitoring 623 |
| Significant pulmonary or cardiac disease | Platinum/pemetrexed (often preferred) | Risk of immune-mediated pneumonitis/myocarditis with dual ICPi; chemotherapy may be safer in high-risk cardiopulmonary patients 123 |
Practical notes for each option:
- If choosing platinum/pemetrexed: mandate folate (400–1000 mcg/day), vitamin B12 (1 mg IM 1 week before cycle 1 and every 3 cycles), and dexamethasone 4 mg BID day −1 to +1 of pemetrexed; recheck creatinine clearance each cycle; hold for ANC <1500 or platelets <100,000; dose-reduce per label for grade 3–4 events 67.
- If choosing nivolumab + ipilimumab: confirm PS 0–1; baseline TSH/free T4, LFTs, creatinine, glucose; educate on irAE symptoms; assess at each infusion; labs every 2–4 weeks; have corticosteroids available; involve subspecialists early (GI for colitis, pulmonology for pneumonitis, endocrinology for thyroiditis/adrenalitis). Endocrine irAEs commonly require lifelong replacement 1121826.
Bottom line
- For fit patients with non-epithelioid MPM (PS 0–1), nivolumab plus ipilimumab should be the default first-line regimen given its substantial survival advantage and durability 11421.
- For epithelioid MPM with PS 0–1, both nivolumab plus ipilimumab and platinum/pemetrexed are reasonable. Immunotherapy offers a modest OS benefit with a durable tail and a chemotherapy-sparing course; chemotherapy remains appropriate when faster tumor control, more predictable toxicity, organ dysfunction, or autoimmune risk favor it. Shared decision-making is key 11420.
- For PS ≥2 or frail elderly patients, outcomes with dual checkpoint blockade are poor in real-world practice; consider platinum/pemetrexed in selected cases or best supportive care, aligning with goals and tolerability 41322.
- Regardless of choice, anticipate and proactively manage toxicities: supplementation and renal surveillance for chemotherapy, and structured irAE monitoring and rapid steroid initiation for immunotherapy 167121826.
These recommendations align with NCCN/ESMO guidance and regulatory approvals in the US and EU, emphasizing histology-driven selection, performance status, and comorbidity assessment to optimize first-line therapy for unresectable MPM 14232425.