SUMMARY: The FDA on September 19, 2024 approved Amivantamab-vmjw (RYBREVANT®) with Carboplatin and Pemetrexed for adult patients with locally advanced or metastatic Non-Small Cell Lung Cancer (NSCLC) with Epidermal Growth Factor Receptor (EGFR) exon 19 deletions or exon 21 L858R substitution mutations, whose disease has progressed on or after treatment with an EGFR tyrosine kinase inhibitor. 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.
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.
The efficacy of Amivantamab was assessed in the Phase 3 MARIPOSA-2 trial, a multicenter, open-label study involving 657 patients. These participants, all with EGFR-mutant NSCLC, who had progressed on Osimertinib treatment, were randomly assigned in a 1:2:2 ratio to receive either Amivantamab with Carboplatin and Pemetrexed (referred to as Amivantamab plus chemotherapy-N=131), Carboplatin and Pemetrexed alone (chemotherapy alone-N=263), or Amivantamab combined with other regimens (N=263). Eligible patients had documented presence of EGFR exon 19 deletion or exon 21 L858R mutation and experienced disease progression after receiving Osimertinib as their most recent line of therapy. Patients received Amivantamab 1400 mg IV (1750 mg for body weight 80 kg or greater) weekly for the first 4 weeks, then 1750 mg (2100 mg for body weight 80 kg or greater) every 3 weeks starting at cycle 3 (week 7). The first Amivantamab infusion was split over 2 days, with 350 mg IV on cycle 1, day 1 and the remainder on cycle 1, day 2. Chemotherapy consisted of Carboplatin AUC 5 IV, starting on day 1 every 3 weeks for the first 4 cycles along with Pemetrexed 500 mg/m2 IV every 3 weeks until disease progression. The median age was 62 years, 48% of patients were Asian and approximately 70% of patients had Osimertinib as first line treatment and 30% had Osimertinib as second line treatment. Randomization was stratified by Osimertinib line of therapy (first or second), and race (Asian or non-Asian). All three treatment groups were well balanced. The Primary endpoint of the study was Progression-Free Survival (PFS), assessed by Blinded Independent Central Review (BICR). Key Secondary endpoints included Overall Survival (OS), Overall Response Rate (ORR), Time to Treatment Discontinuation (TTD), Time to Subsequent Therapy (TTST), Progression-Free Survival after first subsequent therapy (PFS2) and Time to Symptomatic Progression (TTSP).
At a median follow-up of 8.7 months, the PFS was significantly longer for Amivantamab plus chemotherapy versus chemotherapy alone. The median PFS was 6.3 months in the Amivantamab plus chemotherapy group and 4.2 months in the chemotherapy alone group (HR for disease progression or death=0.48; P<0.0001), indicating a a 52% reduction in the risk of progression or death. The ORR was significantly higher in the Amivantamab plus chemotherapy group at 53%, compared to 29% in the chemotherapy alone group (P<0.0001).
In the prespecified second interim analysis, a numerical improvement in OS was noted for the Amivantamab plus chemotherapy group with a median OS of 17.7 months compared to 15.3 months for the chemotherapy alone group (HR=0.73; P=0.039). However, this did not meet the prespecified significance level.
With regards to Post-Progression Endpoints, the median TTD was significantly longer in the Amivantamab plus chemotherapy group versus chemotherapy alone group (10.4 months versus 4.5 months; HR=0.42; P<0.0001). The Median TTST was also prolonged in the Amivantamab plus chemotherapy group versus chemotherapy alone group (12.2 months compared to 6.6 months HR=0.51; P< 0.0001). The median PFS2 was significantly longer in the Amivantamab plus chemotherapy group compared to the chemotherapy alone group (16.0 months versus 11.6 months (HR= 0.64; P=0.002). Common adverse reactions observed in patients receiving Amivantamab plus chemotherapy included rash, infusion-related reactions, fatigue, nail toxicity, nausea, constipation, edema, stomatitis, decreased appetite, musculoskeletal pain, vomiting, and COVID-19 infection.
In conclusion, the results from the MARIPOSA-2 trial provide compelling evidence for the use of Amivantamab in combination with Carboplatin and Pemetrexed in the treatment of advanced EGFR-mutant NSCLC post-Osimertinib progression. While the PFS outcomes were significantly improved, the OS benefits, promising as they may be, require further follow-up for conclusive results. The final Overall Survival analysis will be eagerly awaited, as it will further illuminate the long-term efficacy of this treatment approach.
Amivantamab plus chemotherapy vs chemotherapy in EGFR-mutated, advanced non-small cell lung cancer after disease progression on osimertinib: Second interim overall survival from MARIPOSA-2. Popat S, Reckamp KL, Califano R, et al. Presented at: 2024 ESMO Congress; September 13-17, 2024; Barcelona, Spain. LBA54.
