The New England Journal of Medicine SEPTEMBER 07, 2025

Overall Survival with Amivantamab–Lazertinib in EGFR-Mutated Advanced NSCLC

Byoung Chul Cho, Shun Lu, et al.

Bottom Line

In patients with previously untreated EGFR-mutated advanced non-small cell lung cancer, the combination of amivantamab and lazertinib significantly improved overall survival compared to osimertinib monotherapy.

Key Findings

1. At a median follow-up of 37.8 months, amivantamab–lazertinib demonstrated a significant improvement in overall survival (OS) compared to osimertinib (Hazard Ratio [HR] 0.75; 95% CI, 0.61–0.92; P=0.005).
2. The 3-year OS rate was 60% in the amivantamab–lazertinib group compared to 51% in the osimertinib group.
3. The combination significantly delayed symptomatic progression, with a median time to symptomatic progression of 43.6 months versus 29.3 months with osimertinib (HR 0.69).
4. The combination of amivantamab and lazertinib was associated with a higher incidence of Grade 3 or higher adverse events (80%) compared to osimertinib monotherapy (52%), including increased rates of rash, infusion-related reactions, and venous thromboembolism.

Study Design

Design
RCT
Open-Label (for experimental arm)
Sample
1,074
Patients
Duration
37.8 mo
Median
Setting
Multicenter, global
Population Patients with previously untreated, locally advanced or metastatic non-small cell lung cancer (NSCLC) with EGFR exon 19 deletions or L858R substitution mutations.
Intervention Amivantamab in combination with lazertinib.
Comparator Osimertinib monotherapy.
Outcome Progression-free survival (PFS) as assessed by blinded independent central review.

Study Limitations

The open-label nature of the amivantamab–lazertinib intervention compared to the blinded osimertinib arm may introduce potential bias.
The increased toxicity profile (notably Grade 3+ adverse events) requires diligent monitoring and management strategies.
Optimal sequencing of this combination compared to other emerging first-line regimens, such as osimertinib plus chemotherapy, remains a subject of ongoing clinical debate.

Clinical Significance

This study establishes amivantamab–lazertinib as a chemotherapy-free, first-line standard-of-care option for patients with EGFR-mutated metastatic NSCLC, offering a clear survival benefit, though it requires robust management of treatment-related toxicities.

Historical Context

Third-generation EGFR tyrosine kinase inhibitors like osimertinib previously defined the first-line treatment landscape for EGFR-mutated NSCLC; however, inevitable resistance necessitated the investigation of dual inhibition (e.g., targeting both EGFR and MET) to improve durability of response and survival.

Guided Discussion

High-yield insights from every perspective

Med Student
Medical Student

Amivantamab is a bispecific antibody targeting both EGFR and MET. Why is targeting MET simultaneously particularly important in the context of treating EGFR-mutated non-small cell lung cancer?

Key Response

MET amplification is a common mechanism of acquired resistance to third-generation EGFR tyrosine kinase inhibitors (TKIs) like osimertinib. By targeting both receptors from the start, the combination of amivantamab and lazertinib aims to delay or prevent the emergence of MET-driven resistance clones, leading to more durable responses.

Resident
Resident

The MARIPOSA trial reported a higher incidence of venous thromboembolism (VTE) in the amivantamab–lazertinib group compared to the osimertinib group. What are the clinical implications for patient monitoring and prophylaxis when initiating this combination therapy?

Key Response

In MARIPOSA, VTE occurred in approximately 10% of patients in the combination arm. Clinicians must be vigilant for signs of DVT/PE, and current protocols (including the trial's updated safety measures) often recommend prophylactic anticoagulation (e.g., with LMWH or DOACs) for the first four months of treatment to mitigate this specific risk.

Fellow
Fellow

While the MARIPOSA trial demonstrated superior progression-free survival (PFS) and overall survival (OS) for the combination, osimertinib remains the standard for many due to its CNS penetration. How does the intracranial activity of the amivantamab–lazertinib combination compare to osimertinib monotherapy in patients with baseline brain metastases?

Key Response

Lazertinib is a highly CNS-penetrant third-generation TKI similar to osimertinib. Subgroup analyses from MARIPOSA suggest that the combination maintains intracranial efficacy comparable to osimertinib, addressing concerns that the larger amivantamab molecule might not provide additional CNS protection while ensuring the TKI component still covers the 'sanctuary site' of the brain.

Attending
Attending

Given the overall survival benefit reported in the MARIPOSA trial, how should the trade-off between increased efficacy and the logistical burden of bi-weekly infusions and infusion-related reactions (IRRs) influence the shared decision-making process for a newly diagnosed patient?

Key Response

The OS benefit (HR 0.80) establishes a new efficacy benchmark, but the combination requires intravenous access, frequent clinic visits for amivantamab infusions, and carries a high IRR rate (approx. 63% on first dose). For elderly patients or those with poor performance status, the oral convenience and lower toxicity profile of osimertinib may still outweigh the survival gains of the combination.

Scholarly Review

Critical appraisal through the lens of expert reviewers and guideline development

PhD
PhD

The MARIPOSA trial utilizes a 1:1:1 randomization including a lazertinib monotherapy arm. What is the statistical and biological rationale for including this third arm, and how does it strengthen the interpretation of the amivantamab–lazertinib synergy?

Key Response

Including lazertinib monotherapy allows researchers to isolate the contribution of amivantamab. It proves that the observed superiority over osimertinib is due to the combination's synergistic bispecific targeting and ADCC activity rather than lazertinib simply being a more potent TKI than osimertinib, thereby validating the biological hypothesis of dual-pathway inhibition.

Journal Editor
Journal Editor

In the MARIPOSA trial, the control arm was osimertinib monotherapy, which is the established global standard. However, considering the primary endpoint was PFS and the secondary was OS, how might the lack of a mandatory crossover to amivantamab upon progression in the osimertinib arm affect the purity of the OS signal?

Key Response

If control-group patients do not have access to amivantamab-based regimens at progression (which reflect the 'best possible' subsequent care), the OS benefit might be inflated by the difference in access to potent salvage therapies rather than the front-line combination itself. Editors must scrutinize the 'post-progression therapy' data to ensure the OS advantage is truly intrinsic to the first-line setting.

Guideline Committee
Guideline Committee

Should the NCCN and ESMO guidelines elevate amivantamab–lazertinib to a 'Preferred' (Category 1) status alongside osimertinib for first-line EGFR-mutant NSCLC, or does the safety profile warrant a 'Useful in Certain Circumstances' designation?

Key Response

Current NCCN guidelines highly value osimertinib for its ease of use and safety. While MARIPOSA provides Level 1 evidence for OS improvement, the Guideline Committee must weigh this against the Grade 3+ adverse event rate (75% vs 28% for osimertinib). A 'Preferred' status is likely given the OS data, but with specific caveats regarding VTE prophylaxis and the management of dermatologic toxicities that are significantly more prevalent with the combination.

Clinical Landscape

Noteworthy Related Trials

2018

FLAURA Trial

n = 556 · NEJM

Tested

Osimertinib

Population

Untreated EGFR-mutated advanced NSCLC

Comparator

Gefitinib or Erlotinib

Endpoint

Progression-free survival

Key result: Osimertinib showed significantly longer progression-free survival compared to first-generation EGFR inhibitors.
2021

CHRYSALIS Trial

n = 114 · JCO

Tested

Amivantamab

Population

EGFR Exon 20 insertion-mutated NSCLC progressing after platinum-based chemotherapy

Comparator

None (single-arm)

Endpoint

Overall response rate

Key result: Amivantamab demonstrated durable clinical activity and a manageable safety profile in patients with EGFR exon 20 insertion mutations.
2023

FLAURA2 Trial

n = 557 · NEJM

Tested

Osimertinib plus platinum-pemetrexed chemotherapy

Population

Untreated EGFR-mutated advanced NSCLC

Comparator

Osimertinib monotherapy

Endpoint

Progression-free survival

Key result: The addition of chemotherapy to osimertinib significantly improved progression-free survival compared to osimertinib alone.

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