ipilimumab

Overview

Ipilimumab is a monoclonal antibody used in cancer immunotherapy. It targets cytotoxic T-lymphocyte associated protein 4 (CTLA-4), an immune checkpoint receptor that normally dampens T-cell activation. By blocking CTLA-4, ipilimumab enhances antitumor immune responses and can promote cytotoxic T cell activity against malignant cells. It is therefore classified as an immune checkpoint inhibitor and is used primarily in combination regimens rather than as a conventional cytotoxic therapy.

Clinically, ipilimumab has been studied across multiple solid tumors, including melanoma, renal cell carcinoma, hepatocellular carcinoma, bladder cancer, uveal melanoma, and rare cancers with brain metastases. Recent research continues to evaluate its role in dual checkpoint inhibitor with nivolumab, as well as in combination with local or systemic therapies such as percutaneous hepatic perfusion, BRAF/MEK inhibitors, and (chemo)radiotherapy. These studies reflect its ongoing importance in checkpoint inhibitor and in treatment strategies for metastatic disease, including brain metastases and liver-dominant tumors.

Focus of Latest Publications

Recent publications underscore the expanding role of ipilimumab in combination with nivolumab across diverse malignancies as a dual immune checkpoint inhibitor targeting CTLA-4 and PD-1/PD-L1. Large randomized trials and real-world cohort studies have confirmed clinical benefits in multiple cancer types. The CheckMate 9DW trial demonstrated that nivolumab plus ipilimumab provided superior overall survival, tumor response rates, and quality of life compared with lenvatinib or sorafenib in patients with unresectable hepatocellular carcinoma, establishing this regimen as an effective first-line treatment. In neoadjuvant melanoma therapy (PRADO trial), the combination achieved 5-year outcomes of 86% overall survival, 74% relapse-free survival, and 71% event-free survival, with ongoing immune-related adverse events in survivors predominantly consisting of vitiligo and hypothyroidism.

The combination is being actively studied across solid malignancies including metastatic renal cell carcinoma, esophageal squamous cell carcinoma, muscle-invasive bladder cancer (including in cisplatin-ineligible patients), and colorectal cancer. Real-world evidence from multi-institutional cohorts examining ipilimumab plus nivolumab in esophageal squamous cell carcinoma addresses practical efficacy, safety profiles, and host-related biomarkers relevant to immunotherapy response. Clinical prognostic scoring systems are being developed to stratify patient outcomes with this combination; for example, a three-factor clinical score has been created to identify subsets of metastatic renal cell carcinoma patients likely to derive durable disease control from first-line nivolumab plus ipilimumab therapy.

Emerging evidence supports ipilimumab-based combination strategies in rare and ultra-rare cancers, including gestational trophoblastic neoplasia, angiosarcoma, alveolar soft part sarcoma, and neuroendocrine carcinomas, where patients often face limited treatment alternatives. The NCI/SWOG DART trial demonstrated clinically meaningful activity of nivolumab plus ipilimumab across multiple rare cancer histologies without biomarker selection, with some patients achieving durable disease-free survival years after treatment. Treatment approaches are evolving to enhance efficacy: NP-101, a Nigella sativa formulation, combined with nivolumab and ipilimumab in metastatic extrapulmonary neuroendocrine carcinomas refractory to chemotherapy achieved 41.7% objective response rate and 10.5-month median overall survival with manageable tolerability. Percutaneous hepatic perfusion combined with ipilimumab and nivolumab is being evaluated in metastatic uveal melanoma to simultaneously address hepatic and extrahepatic disease burden.

Biomarker research continues to refine patient selection for ipilimumab-based therapy. In neoadjuvant melanoma, major pathologic response correlated with high tumor mutational burden, elevated interferon-gamma signature, and PD-L1 expression ≥1%, with combined high expression of these markers yielding 100% major pathologic response and 100% 5-year event-free survival. Exposure-response relationships between ipilimumab and nivolumab are being characterized across tumor types to optimize dosing. Ongoing work is also examining treatment discontinuation strategies; for example, in melanoma brain metastases, outcomes are being assessed following discontinuation within 24 months versus continued treatment. These studies collectively demonstrate that while ipilimumab in combination with nivolumab represents an effective immunotherapeutic approach across diverse malignancies, refinement of patient selection through biomarkers, optimization of dosing and duration, and exploration of synergistic combinations remain key ongoing research priorities.

Key Publications

• NEWJun Real-world outcomes of ipilimumab plus nivolumab in esophageal squamous cell carcinoma: a multi-institutional large cohort study. (Cancer immunology, immunotherapy : CII, 2026, PMID 42289036): "Combination immune checkpoint inhibition with ipilimumab plus nivolumab (NIVO + IPI) has shown promising efficacy in advanced esophageal squamous cell carcinoma (ESCC) in the CheckMate648 trial."
• Jul Combos New and Old Counter PD-(L)1 Resistance, Treat Rare Cancers. (Cancer discovery, 2026, PMID 42240229): "As well, an update on the recently published DART (NCI/SWOG S1609) study indicates that the classic combination of ipilimumab with nivolumab may benefit even more rare cancers, including gestational trophoblastic neoplasia."
• Jun Three-factor Clinical Score for First-line Nivolumab Plus Ipilimumab in Metastatic Renal Cell Carcinoma. (Anticancer research, 2026, PMID 42203341): "Nivolumab plus ipilimumab (NIVO-IPI) provides durable disease control in a subset of patients with metastatic renal cell carcinoma (mRCC)."
• Jun The case for tumour-agnostic reimbursement of dual immunotherapy. (European journal of cancer (Oxford, England : 1990), 2026, PMID 42106259): "...tumour-agnostic reimbursement of nivolumab and ipilimumab in Australia."
• May Discontinuation of combo immunotherapy and outcome of patients with melanoma brain metastases. (Journal for immunotherapy of cancer, 2026, PMID 42082273): "Nivolumab plus ipilimumab (COMBO) is the standard treatment for asymptomatic melanoma brain metastases (MBM),"
• May NP-101 in combination with nivolumab and ipilimumab in metastatic extrapulmonary neuroendocrine carcinomas (EP-NECs): A pilot study. (Endocrine-related cancer, 2026, PMID 42012995): "This pilot study evaluated the tolerability and efficacy of NP-101 plus nivolumab and ipilimumab in patients with metastatic EP-NECs refractory to first-line platinum-based chemotherapy."
• Apr A plain language summary of the CheckMate 9DW study: nivolumab in combination with ipilimumab for unresectable hepatocellular carcinoma (advanced liver cancer). (Future oncology (London, England), 2026, PMID 41981891): "The goal of the CheckMate 9DW study was to find out if the combination of two immunotherapy drugs (nivolumab plus ipilimumab) works better than the older drugs (lenvatinib or sorafenib) in people with unresectable HCC."
• Apr A "one-two punch" strategy to reverse immunosuppressive metabolism and activate T-cell immunity for enhanced cancer checkpoint immunotherapy. (Journal of nanobiotechnology, 2026, PMID 41975460): "Particularly, metabolic reprogramming driven by hypoxia and the Warburg effect establishes an immunosuppressive microenvironment that inhibits T-cell-mediated antitumor immunity."
• Apr Comparative efficacy and safety of nivolumab-based combination therapies (with ipilimumab or binimetinib) in patients with microsatellite-stable and microsatellite-instability-high metastatic colorectal cancer: a systematic review and meta-analysis. (Clinical & translational oncology : official publication of the Federation of Spanish Oncology Societies and of the National Cancer Institute of Mexico, 2026, PMID 41934582): "Nivolumab-based combination regimens, which include ipilimumab or binimetinib as components, have shown potential to improve treatment results, but existing studies provide incomplete evidence for their effectiveness."
• Apr Percutaneous hepatic perfusion combined with ipilimumab and nivolumab for metastatic uveal melanoma (CHOPIN): a single-centre, open-label, randomised, phase 2 trial. (The Lancet. Oncology, 2026, PMID 41785896): "Immune checkpoint inhibitors ipilimumab and nivolumab show limited activity in uveal melanoma, although retrospective studies suggest improved outcomes when combined with liver-directed therapies."