The New England Journal of Medicine SEPTEMBER 15, 2024

Nivolumab plus Ipilimumab or Nivolumab Alone versus Ipilimumab Alone in Advanced Melanoma (CheckMate-067)

Jedd D. Wolchok, Vanna Chiarion-Sileni, Piotr Rutkowski, et al.

Bottom Line

The CheckMate-067 trial demonstrated that the combination of nivolumab and ipilimumab, as well as nivolumab monotherapy, provides significantly durable, long-term survival benefits compared to ipilimumab monotherapy in patients with previously untreated advanced melanoma.

Key Findings

1. At 10 years of minimum follow-up, the median overall survival (OS) was 71.9 months (95% CI, 38.2 to 114.4) for the combination group, compared to 36.9 months (95% CI, 28.2 to 58.7) for nivolumab monotherapy and 19.9 months (95% CI, 16.8 to 24.6) for ipilimumab monotherapy.

2. The hazard ratio for death was 0.53 (95% CI, 0.44 to 0.65) for the combination versus ipilimumab and 0.63 (95% CI, 0.52 to 0.76) for nivolumab monotherapy versus ipilimumab.

3. Melanoma-specific survival at 10 years was superior in the nivolumab-containing arms, and for patients who were alive and progression-free at 3 years, 10-year melanoma-specific survival rates reached 96% with the combination and 97% with nivolumab alone.

4. Treatment-related grade 3 or 4 adverse events occurred more frequently in the combination arm (approximately 59%) compared to nivolumab (22%) and ipilimumab (28%) monotherapy, with no new safety signals reported in long-term follow-up.

Study Design

Design

RCT

Double-Blind

Sample

945

Patients

Duration

10 yr

Median

Setting

Multicenter, global

Population Patients aged 18 years or older with previously untreated, unresectable stage III or stage IV melanoma.

Intervention Nivolumab (1 mg/kg) plus ipilimumab (3 mg/kg) every 3 weeks for four doses, followed by nivolumab (3 mg/kg) every 2 weeks.

Comparator Ipilimumab (3 mg/kg) every 3 weeks for four doses plus placebo.

Outcome Overall survival and progression-free survival.

Study Limitations

• The study was not powered to formally compare the combination therapy against nivolumab monotherapy, rendering these comparisons descriptive.

• The higher rate of treatment-related grade 3-4 adverse events in the combination arm necessitates careful patient selection and monitoring.

• The long-term follow-up reflects survival outcomes in a rapidly evolving treatment landscape where patients may have received subsequent therapies post-progression, which could confound survival data.

• While survival curves reached a plateau, the trial design does not fully account for the complex interaction between immune-related toxicities and the durability of response.

Clinical Significance

CheckMate-067 established dual checkpoint blockade (anti-PD-1 and anti-CTLA-4) as a standard-of-care, providing unprecedented long-term survival outcomes that have fundamentally transformed the management of metastatic melanoma from a terminal condition to one with potential for durable, long-term remission in a significant proportion of patients.

Historical Context

Prior to 2011, advanced melanoma was characterized by extremely poor prognosis. The approval of ipilimumab, the first checkpoint inhibitor, provided the first survival signal, which was subsequently greatly expanded by the development of PD-1 inhibitors like nivolumab. CheckMate-067 represents the landmark trial confirming that combining these two distinct immunologic mechanisms offers superior long-term survival benefits compared to sequential or monotherapy approaches.

Guided Discussion

High-yield insights from every perspective

Med Student

Medical Student

How do the mechanisms of action of the two immune checkpoint inhibitors used in CheckMate-067—nivolumab and ipilimumab—differ in their targeting of T-cell regulation, and why is this combination biologically synergistic?

Key Response

Ipilimumab targets CTLA-4, which acts primarily during the 'priming' phase of T-cell activation in the lymph nodes by blocking the inhibitory signal from B7-1/B7-2 on APCs. Nivolumab targets PD-1, which acts during the 'effector' phase within the tumor microenvironment by preventing tumor cells from inactivating T-cells via the PD-L1 pathway. Combining them targets two distinct, non-redundant pathways of immune suppression, leading to enhanced anti-tumor activity.

Resident

Based on the CheckMate-067 results, if a patient with metastatic melanoma develops a Grade 3 immune-related adverse event (irAE) necessitating the permanent discontinuation of the nivolumab plus ipilimumab combination after only two doses, what is the expected impact on their long-term survival probability?

Key Response

Sub-group analyses of CheckMate-067 demonstrated that patients who discontinued the combination therapy due to toxicities (even early in treatment) had similar objective response rates and overall survival durations as those who completed the full induction phase. This suggests that the immune 'reset' can occur early and be durable even without prolonged dosing.

Fellow

In the context of the CheckMate-067 long-term follow-up, how should a patient's BRAF mutation status and baseline LDH level influence the clinical choice between nivolumab plus ipilimumab versus nivolumab monotherapy?

Key Response

While both nivolumab-containing arms outperformed ipilimumab alone, descriptive analyses suggest that patients with BRAF mutations and those with elevated LDH (poor prognostic markers) may derive a numerically greater magnitude of benefit from the combination therapy than from nivolumab monotherapy. However, this must be weighed against the significantly higher rate of Grade 3/4 toxicities (59% vs 23%) in the combination arm.

Attending

CheckMate-067 reports a 'plateau' in the overall survival curve at the 6.5-year mark and beyond. How does this data redefine our approach to 'survivorship' and the cessation of therapy in patients who achieve a complete response (CR)?

Key Response

The survival plateau suggests that metastatic melanoma, once universally fatal, can now be potentially cured or managed as a chronic condition in ~50% of patients. This implies we can safely stop treatment in many patients with CR, but it also necessitates long-term monitoring for 'chronic' irAEs and secondary malignancies, as well as addressing the psychological and financial burden of long-term survivorship.

Scholarly Review

Critical appraisal through the lens of expert reviewers and guideline development

PhD

Critique the statistical power of CheckMate-067 regarding its ability to compare the efficacy of nivolumab plus ipilimumab directly against nivolumab monotherapy. Why is this a limitation for clinical decision-making?

Key Response

The trial was specifically powered to compare the nivolumab-containing regimens to the ipilimumab monotherapy arm (the standard of care at the time). It was not formally powered to compare the combination directly to nivolumab monotherapy. Consequently, any perceived differences between the two nivolumab arms are based on descriptive, post-hoc observations rather than definitive statistical significance, making it difficult to prove the absolute necessity of the combination for all patients.

Journal Editor

As a peer reviewer, how would you evaluate the ethical and scientific validity of the control arm (ipilimumab monotherapy) in the later years of the CheckMate-067 trial, and what are the implications for the trial's generalizability to modern practice?

Key Response

While ipilimumab was the standard when the trial launched, PD-1 inhibitors (like nivolumab or pembrolizumab) became the standard of care shortly thereafter. This makes the comparison to ipilimumab 'historically' important but less relevant to contemporary practice where the primary question is whether combination therapy is superior to PD-1 monotherapy. A tough reviewer would flag that the trial provides an 'easy' win against an obsolete control but lacks the head-to-head power for the modern clinical question.

Guideline Committee

Current NCCN and ESMO guidelines list both nivolumab monotherapy and nivolumab plus ipilimumab as Category 1, preferred first-line options. Does the 6.5-year CheckMate-067 data provide sufficient evidence to recommend the combination over monotherapy for PD-L1 negative patients specifically?

Key Response

CheckMate-067 exploratory analyses showed that patients with low PD-L1 expression (<1%) had a more pronounced improvement in progression-free survival with the combination compared to nivolumab monotherapy. While guidelines generally allow for either, this evidence suggests that PD-L1 negative status may be a critical biomarker for prioritizing combination therapy despite the increased toxicity, whereas PD-L1 positive patients might achieve similar outcomes with less toxic monotherapy.

Clinical Landscape

Noteworthy Related Trials

2015

KEYNOTE-006

n = 834 · NEJM

Tested

Pembrolizumab

Population

Advanced melanoma

Comparator

Ipilimumab

Endpoint

Progression-free survival and overall survival

Key result: Pembrolizumab demonstrated superior progression-free and overall survival compared to ipilimumab in patients with advanced melanoma.

2015

CheckMate-037

n = 405 · NEJM

Tested

Nivolumab

Population

Ipilimumab-refractory advanced melanoma

Comparator

Investigator-choice chemotherapy

Endpoint

Objective response rate

Key result: Nivolumab provided durable objective responses in patients who had progressed after treatment with ipilimumab and, if BRAF mutation-positive, a BRAF inhibitor.

2015

COMBI-d

n = 423 · NEJM

Tested

Dabrafenib plus Trametinib

Population

BRAF V600E/K-mutated metastatic melanoma

Comparator

Dabrafenib monotherapy

Endpoint

Progression-free survival

Key result: The combination of dabrafenib and trametinib significantly improved progression-free survival compared to dabrafenib alone.

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