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 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 target the EGFR signaling cascade. However, patients eventually will 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 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 downregulates 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 (LECLAZA®) 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.
Amivantamab given intravenously along with Lazertinib demonstrated antitumor activity in EGFR-mutated advanced NSCLC. PALOMA-3 study evaluated the efficacy, PharmacoKinetics (PK), and safety of a subcutaneous formulation of Amivantamab given along with Lazertinib, compared to intravenous (IV) administration given along with Lazertinib, in patients with EGFR Exon 19 deletion or L858R-mutated advanced NSCLC.
PALOMA-3 is a randomized, controlled Phase III trial in which 418 patients who had disease progression on Osimertinib and platinum-based chemotherapy were randomly assigned 1:1 to receive subcutaneous (SC) or intravenous (IV) Amivantamab, both combined with Lazertinib, with 206 patients (N=206) assigned to the SC arm and 212 patients (N=212) assigned to the IV arm. SC Amivantamab was administered at 1600 mg weekly for the first 4 weeks and then every 2 weeks, while IV Amivantamab was given at the approved dose of 1050 mg. Lazertinib was administered at 240 mg orally daily in both groups. Prophylactic anticoagulation was recommended for the first 4 months. The median age of patients was 61 years, 67% were female, 61% were Asian, patients had received a median of two prior lines of therapy, and 34% had a history of brain metastases. Co-primary pharmacokinetic noninferiority endpoints were trough concentrations (C trough on Cycle 2 Day 1 or Cycle 4 Day 1) and Cycle 2 AUC Day1-Day 15. Secondary endpoints included Objective Response Rate (ORR) and Progression Free Survival (PFS). Overall Survival (OS) was an exploratory endpoint.
At a median follow up of 7 months, the trial met both co-primary PK endpoints. SC Amivantamab demonstrated non-inferiority compared to IV in terms of trough concentrations and AUC, with geometric mean ratios favoring SC administration. SC Amivantamab along with Lazertinib showed a non-inferior ORR (30.1%) compared to IV (32.5%), meeting the predefined noninferiority criteria (RR=0.92; P=0.001). Among confirmed responders, SC administration resulted in a longer median DoR (11.2 months) compared to 8.3 months with IV administration. Although not statistically significant, SC Amivantamab along with Lazertinib showed a favorable trend in PFS (median 6.1 months versus 4.3 months for IV; HR 0.84, P=0.20). Overall Survival was notably longer with SC administration (HR 0.62; P=0.017), with 65% alive at 12 months in the SC arm versus 51% in the IV group.
SC administration significantly reduced Infusion-Related Reactions by 5 fold (13% versus 66% for IV), with no severe reactions leading to hospitalization in the SC arm. Prophylactic anticoagulation reduced Venous Thromboembolism (VTE) risk (9% SC versus 14% IV) and the overall incidence was lower in the SC group, emphasizing safety benefits. Across both treatment groups, VTE incidence was 10% for patients who received prophylactic anticoagulants versus 21% for patients who did not. With regards to patient experience, SC administration took less than 5 minutes, significantly shorter than IV (initial infusion 5 hours), contributing to higher patient satisfaction (85% versus 35% found SC convenient at end of treatment).
It was concluded that the PALOMA-3 trial demonstrated that SC administration of Amivantamab is non-inferior to IV in terms of PK and efficacy endpoints and represents a paradigm shift towards more patient-friendly and effective treatment options for EGFR-mutated NSCLC, with lower rates of Infusion-Related Reactions and VTE.
Subcutaneous amivantamab vs intravenous amivantamab, both in combination with lazertinib, in refractory EGFR-mutated, advanced non-small cell lung cancer (NSCLC): Primary results, including overall survival (OS), from the global, phase 3, randomized controlled PALOMA-3 trial. Leighl NB, Akamatsu H, Lim SM, et al. J Clin Oncol 42, 2024 (suppl 17; abstr LBA8505)
