MSK Pembrolizumab Phase 1 Trial (NCT04897022)

Immunotherapy combinations like nivolumab plus ipilimumab (Opdivo + Yervoy) show median overall survival of 18.1 months for people with mesothelioma, compared to 14.1 months with chemotherapy alone. One-year survival reaches 68%, two-year survival 41%, and three-year survival 23-25% in clinical trials. Five-year survival is 14% with immunotherapy versus 6% with chemotherapy overall, and higher (12-14%) for epithelioid or non-epithelioid subtypes. A meta-analysis of seven randomized trials confirms immunotherapy improves survival across lines of therapy and histologic subtypes.

Asbestos exposure causes multiple cancers, with mesothelioma being the primary one. Mesothelioma is a rare cancer of the thin membranes lining the chest, abdomen, and other organs, and asbestos is responsible for more than 80% of cases. Asbestos also causes lung cancer, laryngeal cancer, and ovarian cancer. The International Agency for Research on Cancer and the U.S. Environmental Protection Agency classify all types of asbestos as carcinogens.

Mesothelioma has a very poor prognosis, with a median survival of approximately one year from diagnosis and a five-year survival rate of 10-12%. However, it is not universally 100% fatal. Some people with mesothelioma have survived for extended periods with multimodal treatment (surgery, chemotherapy, and radiation), and survival outcomes vary significantly based on cancer stage, histological type, and individual response to treatment. Peritoneal mesothelioma, for example, shows better one-year survival rates (92%) compared to pleural mesothelioma (approximately 73% 1-year survival per SEER, rising to 79.6% for people treated with multimodal surgery, chemotherapy, and radiation), suggesting that type, treatment, and early detection can influence outcomes. While the disease remains highly aggressive and fatal in the majority of cases, advances in treatment protocols continue to improve survival rates incrementally.

No cure exists for mesothelioma, the cancer linked to asbestos exposure. Multimodal treatments, including surgery, chemotherapy, immunotherapy, and radiation, improve survival rates, with 79.6% of people with pleural mesothelioma reaching 1 year and 12% surviving 5 years or more. Ongoing research, such as NCI-funded studies on preventive agents like sulforaphane, explores future options but offers no current cure.

Current evidence from small retrospective series and early clinical trials reports that immune checkpoint inhibitors like pembrolizumab generally appear safe in the perioperative period, with no clear signal that they increase serious surgical complications. Studies in people with melanoma and lung cancer have tested pembrolizumab as neoadjuvant therapy (given up to a few weeks before surgery) and then continued afterward, and did not require long washout periods before operations. One review in multiple tumor types found no Grade III–IV surgical complications within 30 days and concluded there was “no reason to withhold or delay surgery” for people receiving ipilimumab, and that continuing checkpoint inhibitors without interruption “may be feasible and safe.” However, most published data involve limited numbers of people with varying cancers, so authors frequently call for larger prospective studies to confirm whether holding pembrolizumab is unnecessary in all settings.

Pembrolizumab trials across multiple cancers have consistently reported meaningful disease control and survival benefits. In the PEACOCC phase 2 trial for previously treated advanced clear cell gynecologic cancer, 42% of people had progression-free survival at 12 weeks and 25% had an objective response, with a median overall survival of 14.8 months and generally tolerable safety. In the large phase 3 KEYNOTE-042 study for PD-L1–positive advanced non small cell lung cancer, pembrolizumab monotherapy improved overall survival compared with platinum chemotherapy, with 5-year survival rates around 17% to 22% depending on PD-L1 level. Earlier KEYNOTE studies also showed higher long-term survival and durable responses for people receiving pembrolizumab, and lung cancer trials combining pembrolizumab with chemoradiotherapy reported response rates above 70% with manageable pulmonary toxicity. Across trials, researchers concluded that pembrolizumab often provided durable benefit and acceptable safety, which has led investigators to describe it as a standard component of care in several advanced or earlier-stage cancer settings.

Clinical trials that led to KEYTRUDA’s approvals typically capped treatment at about 2 years, and many people with advanced cancers stop around this point if their disease is controlled. For adjuvant settings such as melanoma or non small cell lung cancer after surgery, prescribing information often describes treatment for up to 12 months or until recurrence or unacceptable side effects. In real-world practice, some people with mesothelioma or other cancers discontinue earlier due to immune related side effects, while others continue beyond 2 years when cancer control is durable and toxicity remains manageable. Observational studies report median overall survival of around 15 to 26 months in certain lung cancer groups on pembrolizumab, which aligns with this common 1 to 2 year treatment window.

Costs for pembrolizumab (Keytruda) vary widely by country, health system, and dose schedule. In the United States, the manufacturer’s list price is $12,272 per 3‑week dose and $24,544 per 6‑week dose, although company data report that about 80% of people with commercial or Medicare coverage ultimately pay roughly $0.01 to $2,100 per infusion. In Ireland, health technology assessments have estimated drug acquisition costs of about €134,320 per person per year, with a typical treatment course around €118,000. In Australia, analyses have suggested that weight‑based dosing at 2 mg/kg every 3 weeks could cost the public system about A$5,933 per dose compared with A$7,646 for a fixed 200 mg dose. In India, online marketplace listings show 100 mg vials ranging from roughly ₹10,000 to more than ₹200,000, reflecting a wide spread between different brands and distributors.