SUMMARY: Lung cancer is the second most common cancer in both men and women and accounts for about 13% of all new cancers and 21% of all cancer deaths. The American Cancer Society estimates that for 2025, about 226,650 new cases of lung cancer will be diagnosed and 124,730 patients will die of the disease. Lung cancer is the leading cause of cancer-related mortality in the United States. Non-Small Cell Lung Cancer (NSCLC) accounts for approximately 85% of all lung cancers and Adenocarcinoma is now the most frequent histologic subtype of lung cancer. Approximately 10-15% of Caucasian patients and 35-50% of Asian patients with Adenocarcinomas, harbor activating EGFR mutations, and 90% of these mutations are either exon 19 deletions or L858R substitution mutation in exon 21.
Epidermal Growth Factor Receptor (EGFR) plays an important role in regulating cell proliferation, survival and differentiation, and is overexpressed in a variety of epithelial malignancies. EGFR targeted Tyrosine Kinase Inhibitors (TKIs) such as Gefitinib, Erlotinib, Afatinib, Dacomitinib and Osimertinib (TAGRISSO®) target the EGFR signaling cascade. However, patients eventually develop drug resistance due to new EGFR mutations. Another important cause of drug resistance to TKIs is due to the activation of parallel RTK (Receptor Tyrosine Kinase) pathways such as Hepatocyte Growth Factor/Mesenchymal-Epithelial Transition factor (HGF/MET) pathway, thereby bypassing EGFR TKI inhibitors. These patients are often treated with platinum-based chemotherapy as the next line of therapy, resulting in a median Progression Free Survival of about 5 months.
Amivantamab (RYBREVANT®) is a fully human bispecific antibody directed against EGFR and MET receptors. Amivantamab binds extracellularly and simultaneously blocks ligand-induced phosphorylation of EGFR and c-MET, inhibiting tumor growth and promoting tumor cell death. Further, Amivantamab down regulates receptor expression on tumor cells thus preventing drug resistance mediated by new emerging mutations of EGFR or c-MET. By binding to the extracellular domain of the receptor protein, Amivantamab can bypass primary and secondary TKI resistance at the active site. Amivantamab also engages effector cells such as Natural Killer cells, monocytes, and macrophages via its optimized Fc domain. Amivantamab demonstrated activity against a wide range of activating and resistance mutations in EGFR-mutated NSCLC, and in patients with MET exon 14 skip mutations, as well as patients with EGFR exon 20 insertion mutations, whose disease progressed on or after platinum-based chemotherapy.
Lazertinib (LAZCLUZE®) is a highly selective, third-generation TKI that penetrates the CNS, with demonstrated efficacy in activating EGFR mutations and acquired T790M “gatekeeper” point mutation. Combining Amivantamab with Lazertinib has been shown to provide a synergistic benefit by targeting the extracellular and catalytic EGFR domains. The combination of Amivantamab plus Lazertinib has shown clinically meaningful and durable antitumor activity in patients with previously untreated or Osimertinib-pretreated EGFR-mutated advanced NSCLC, with clinical activity against a broad spectrum of secondary EGFR and MET molecular alterations and even in tumors of patients without an identified resistance mechanism.
The MARIPOSA trial is an international, randomized Phase 3 study, conducted to assess the efficacy and safety of a combination of Amivantamab and Lazertinib as compared with Osimertinib alone, as first-line treatment in patients with EGFR-mutated advanced NSCLC. In this study, a third arm evaluated Lazertinib monotherapy, to dissect the individual contributions of each component in the combination. This study included 1074 patients (N=1074) with untreated EGFR-mutated advanced NSCLC who were randomly assigned in a 2:2:1 ratio to receive Amivantamab plus Lazertinib (N=429), Osimertinib monotherapy (N=429), or Lazertinib monotherapy (N=216). Amivantamab was administered weekly at a dose of 1050 mg IV (or 1400 mg IV in patients with a body weight of 80 kg or more) for the first 4 weeks (cycle 1), with the first infusion split over a period of 2 days (with 350 mg given on cycle 1, day 1, and the remainder given on cycle 1, day 2). Starting at cycle 2, the same Amivantamab dose was administered every 2 weeks. Osimertinib 80 mg and Lazertinib 240 mg were taken orally daily respectively. The median age was 63 years, majority of patients were Asian women or White and had never smoked. Approximately 60% had EGFR exon 19 deletions and 40% had exon 21 L858R mutations. Randomization was stratified according to EGFR mutation type (ex19del or L858R), Asian race (yes or no), and history of brain metastases (yes or no). Crossover was not included in this trial design. The Primary end point was Progression-Free Survival (PFS) in the Amivantamab plus Lazertinib group as compared with the Osimertinib group, as assessed by Blinded Independent Central Review. Secondary end points included Overall Survival (OS), Objective Response (defined as a Complete or Partial Response), Duration of Response, and Safety.
The authors previously reported that the median PFS (Primary endpoint), was significantly longer in the Amivantamab plus Lazertinib group at 23.7 months compared to 16.6 months in the Osimertinib group ((HR for progression or death = 0.70; P<0.001).
The researchers in this publication reported the results of the protocol-specified final Overall Survival analysis.
The combination of Amivantamab plus Lazertinib demonstrated a significant Overall Survival (OS) advantage over Osimertinib in patients with previously untreated, EGFR-mutated advanced NSCLC. After a median follow-up of 37.8 months, treatment with Amivantamab–Lazertinib reduced the risk of death by 25% compared with Osimertinib (HR=0.75; 95% CI, 0.61–0.92; P=0.005). Estimated 3-year OS rates were 60% with the combination versus 51% with Osimertinib, while 24-month OS was 75% and 70%, respectively. These findings were supported by multiple parametric modeling approaches, indicating a projected survival benefit exceeding one year.
A greater proportion of patients in the Amivantamab–Lazertinib arm remained on treatment at data cutoff (38% vs 28%). The combination also prolonged time to symptomatic progression, time to treatment discontinuation, and time to next therapy relative to Osimertinib. Notably, most patients in both groups who discontinued study therapy received subsequent anticancer treatment, primarily chemotherapy-based regimens.
The superior outcomes observed with Amivantamab–Lazertinib are thought to stem from its dual targeting of EGFR and MET pathways, enabling proactive suppression of key resistance mechanisms. This regimen was also associated with a lower frequency of complex acquired resistance (28% vs 43%) and potentially beneficial immune-mediated activity.
Among participants with baseline brain metastases (approximately 40% in each group), intracranial outcomes favored Amivantamab–Lazertinib and were consistent with those from the MARIPOSA-2 trial, supporting its efficacy in CNS disease.
As expected, Grade ≥3 adverse events were more frequent with Amivantamab–Lazertinib (80% vs 52%), most commonly dermatologic reactions, venous thromboembolism, and infusion-related events. However, no new safety signals emerged. Emerging evidence from other studies, such as COCOON, suggests that prophylactic strategies (enhanced dermatologic care, anticoagulation, and optimized infusion protocols) can substantially reduce these toxicities. Furthermore, a newly approved subcutaneous formulation of Amivantamab markedly lowers infusion-related reactions (13% vs 66%) and reduces administration time from hours to minutes while maintaining efficacy.
Overall, the MARIPOSA trial establishes Amivantamab–Lazertinib as a superior first-line, chemotherapy-free option for patients with EGFR-mutated advanced NSCLC, offering meaningful improvements in both Progression-Free and Overall Survival compared with Osimertinib.
Overall Survival with Amivantamab–Lazertinib in EGFR-Mutated Advanced NSCLC. Yang JC, Lu S, Hayashi H, et al. for the MARIPOSA Investigators. N Engl J Med 2025;393:1681-1693.
