Nivolumab (Opdivo) for Mesothelioma

Nivolumab, marketed as Opdivo, is a PD-1 immune checkpoint inhibitor that was approved by the FDA on October 2, 2020, in combination with ipilimumab (Yervoy) for the first-line treatment of adults with unresectable malignant pleural mesothelioma. This approval marked a historic shift in mesothelioma therapy — the first new first-line treatment option in 16 years and the first immunotherapy regimen approved for this disease.¹

Nivolumab works by blocking the programmed death-1 (PD-1) receptor on the surface of T cells. In normal physiology, PD-1 acts as an immune "brake" — when it binds to its ligands (PD-L1 and PD-L2) on other cells, it signals the T cell to reduce its activity. Many cancers, including mesothelioma, exploit this mechanism by expressing high levels of PD-L1 on their surface, effectively hiding from the immune system. By blocking PD-1, nivolumab releases this brake and allows the patient's T cells to recognize and attack mesothelioma cells.²

The combination of nivolumab with ipilimumab is particularly powerful because the two drugs target different immune checkpoints. While nivolumab blocks PD-1, ipilimumab blocks CTLA-4 — another inhibitory receptor that suppresses T cell activation at an earlier stage. This dual checkpoint blockade produces a more robust and sustained anti-tumor immune response than either drug alone, though it also increases the risk of immune-related side effects.³

The FDA approval was based on the CheckMate 743 trial, a landmark phase III study that demonstrated the nivolumab/ipilimumab combination was superior to standard pemetrexed-based chemotherapy in previously untreated unresectable mesothelioma patients. The benefit was particularly pronounced in patients with non-epithelioid (sarcomatoid and biphasic) histology, a population that historically responds poorly to chemotherapy.¹

Nivolumab is administered as part of a specific FDA-approved regimen for mesothelioma and is also being studied in other treatment combinations:¹

FDA-Approved First-Line Regimen

The approved dosing schedule for unresectable malignant pleural mesothelioma:²

• Nivolumab — 360 mg as a 30-minute intravenous infusion every 3 weeks
• Ipilimumab — 1 mg/kg as a 30-minute intravenous infusion every 6 weeks
• Duration — Treatment continues for up to 2 years or until disease progression or unacceptable toxicity
• No vitamin supplementation required — Unlike pemetrexed-based chemotherapy, immunotherapy does not require folic acid or B12 supplementation

CheckMate 743 Trial Results

The pivotal phase III trial randomized 605 patients with previously untreated, unresectable malignant pleural mesothelioma:¹

• Median overall survival — 18.1 months (nivolumab + ipilimumab) vs. 14.1 months (chemotherapy)
• 2-year survival rate — 41% vs. 27%
• Non-epithelioid subgroup — Median OS 18.1 months vs. 8.8 months — a dramatic benefit in a historically difficult-to-treat population
• Epithelioid subgroup — Median OS 18.7 months vs. 16.5 months — a more modest but still meaningful benefit
• Duration of response — Responses to immunotherapy tend to be more durable than chemotherapy responses, with some patients maintaining benefit for years

Second-Line and Ongoing Research

Nivolumab as a single agent has shown activity in previously treated mesothelioma patients. The CONFIRM trial demonstrated improved overall survival with single-agent nivolumab versus placebo in relapsed mesothelioma. Ongoing trials are evaluating nivolumab combined with chemotherapy, targeted agents, and novel immunotherapies for mesothelioma.⁴

The introduction of nivolumab plus ipilimumab has meaningfully improved survival prospects for mesothelioma patients, particularly those with non-epithelioid histology:¹

• Overall population — A 4-month improvement in median overall survival compared to chemotherapy (18.1 vs. 14.1 months), with a 26% reduction in the risk of death
• Long-term survivors — Approximately 41% of patients in the immunotherapy arm were alive at 2 years, with some patients achieving durable responses lasting several years
• Non-epithelioid histology — The greatest benefit was seen in sarcomatoid and biphasic mesothelioma patients, where median survival more than doubled compared to chemotherapy
• Predictive biomarkers — PD-L1 expression and tumor mutational burden are being studied as potential biomarkers to predict which patients will benefit most from immunotherapy

Immunotherapy side effects differ fundamentally from chemotherapy side effects. Nivolumab and ipilimumab can trigger immune-related adverse events (irAEs) — conditions caused by the activated immune system attacking normal tissues:³

• Immune-mediated pneumonitis — Inflammation of the lungs, occurring in 3–5% of patients. Symptoms include new or worsening cough, chest pain, and shortness of breath. Requires prompt reporting and may be treated with corticosteroids. This is particularly important to monitor in mesothelioma patients who may already have compromised lung function
• Colitis (intestinal inflammation) — Diarrhea, abdominal pain, and blood in stool occur in 10–15% of patients, more frequently with the ipilimumab combination. Mild cases are managed with anti-diarrheal medications; severe cases require high-dose corticosteroids and possibly infliximab
• Hepatitis (liver inflammation) — Elevated liver enzymes detected on blood tests, usually asymptomatic. Liver function is monitored before each infusion. Severe cases require treatment interruption and corticosteroids
• Endocrinopathies — The immune system may attack hormone-producing glands, causing thyroid dysfunction (most common), adrenal insufficiency, or hypophysitis (pituitary inflammation). Thyroid function is monitored regularly. Hormone replacement therapy may be needed long-term
• Skin reactions — Rash, itching, and vitiligo (skin depigmentation) are common but usually mild. Topical corticosteroids and antihistamines typically provide adequate relief
• Fatigue — Reported by 25–35% of patients, generally milder than chemotherapy-induced fatigue. May be related to thyroid dysfunction and should be evaluated with thyroid function tests
• Infusion reactions — Fever, chills, and flushing may occur during or shortly after infusion. Most reactions are mild and managed with supportive care

Unlike chemotherapy side effects, immune-related adverse events can occur at any time — even weeks or months after treatment ends. Patients should carry an immunotherapy alert card and inform all healthcare providers that they are receiving checkpoint inhibitor therapy.³