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 2024, about 234,580 new cases of lung cancer will be diagnosed and 125,070 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. Of the three main subtypes of NSCLC, 30% are Squamous Cell Carcinomas (SCC), 40% are Adenocarcinomas and 10% are Large Cell Carcinomas. With changes in the cigarette composition and decline in tobacco consumption over the past several decades, Adenocarcinoma now is the most frequent histological 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, and is approved for the treatment of 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. 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). 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 median PFS 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 Objective Response was 86% in the Amivantamab plus Lazertinib group and 85% in the Osimertinib group. Among patients with a confirmed response (336 in the Amivantamab plus Lazertinib group and 314 in the Osimertinib group), the median response duration was 25.8 months and 16.8 months, respectively. In a planned interim Overall Survival analysis, Hazard Ratio for death with Amivantamab plus Lazertinib was 0.80 (95% CI, 0.61–1.05).
EGFR and MET-related toxic effects were the most common side effects and most adverse events were of grade 1 or 2. The treatment discontinuation due to adverse events occurred in 10% of patients in the Amivantamab plus Lazertinib group versus 3% in the Osimertinib group. The incidence of venous thromboembolic adverse events was higher with Amivantamab Plus Lazertinib than with Osimertinib and most of the thromboembolic events in the Amivantamab plus Lazertinib group occurred during the first 4 months of treatment. This has been attributed to a transitory prothrombotic state caused by a mechanism of rapid tumor-cell death by the Amivantamab plus Lazertinib combination.
In conclusion, the combination of Amivantamab plus Lazertinib demonstrated superior efficacy over Osimertinib as a first-line therapy for EGFR-mutated advanced NSCLC, offering longer Progression-Free Survival and Duration of Response.
Amivantamab plus Lazertinib in Previously Untreated EGFR-Mutated Advanced NSCLC. Cho BC, Lu S, Felip E, et al. for the MARIPOSA Investigators. N Engl J Med 2024;391:1486-1498.
