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.
Immunotherapy with Immune Checkpoint Inhibitors (ICIs) has revolutionized cancer care and has become one of the most effective treatment options, by improving Overall Response Rate and prolongation of survival, across multiple tumor types. These agents target Programmed cell Death protein-1 (PD-1), Programmed cell Death Ligand-1 (PD-L1), Cytotoxic T-Lymphocyte-Associated protein-4 (CTLA-4), and many other important regulators of the immune system. Checkpoint inhibitors unleash the T cells resulting in T cell proliferation, activation, and a therapeutic response. Biomarkers predicting responses to ICIs include Tumor Mutational Burden (TMB), Mismatch Repair (MMR) status, and Programmed cell Death Ligand 1 (PD‐L1) expression.
Pembrolizumab (KEYTRUDA®) is a fully humanized, Immunoglobulin G4, anti-PD-1, monoclonal antibody, that binds to the PD-1 receptor and blocks its interaction with ligands PD-L1 and PD-L2, thereby unleashing the T cells. Five year results from the Phase III KEYNOTE-042 study which included eligible patients with locally advanced/metastatic NSCLC without EGFR/ALK alterations and with PD-L1 Tumor Proportion Score (TPS) 1% or more favored Pembrolizumab over chemotherapy, regardless of PD-L1 TPS.
Ivonescimab (AK112) is a novel bispecific antibody designed to target both PD-1 and Vascular Endothelial Growth Factor (VEGF). Its dual targeting mechanism is intended to enhance the therapeutic efficacy against advanced NSCLC, and has shown promising results in early-phase trials. Dual inhibition of PD-1 and VEGF by Ivonescimab might provide synergistic effects, enhancing therapeutic efficacy beyond what is achieved with PD-L1 inhibition alone.
The HARMONi-2 (AK112-303) is a randomized Phase III study designed to evaluate the efficacy and safety of Ivonescimab compared to Pembrolizumab, a well-established PD-1 inhibitor, in patients with advanced NSCLC. In this study, 398 eligible patients (N=398) from 55 centers in China with untreated locally advanced (Stage IIIB or IIIC) or metastatic (Stage IV) NSCLC were randomly assigned in a 1:1 ratio to receive either Ivonescimab 20 mg/kg administered IV every 3 weeks or Pembrolizumab 200 mg administered IV every 3 weeks. Patients were required to have PD-L1 positive tumors (TPS 1% or more), and patients with known EGFR mutations, ALK rearrangements, or prior systemic therapy were excluded. Randomization was stratified by histology (squamous versus non-squamous), clinical stage (IIIB/IIIC versus IV), and PD-L1 expression levels (TPS 1-49% versus TPS 50% or more).
The Primary endpoint was Progression-Free Survival (PFS), assessed by an Independent Radiographic Review Committee (IRRC). Secondary endpoints included Overall Survival (OS), Investigator-assessed PFS, Objective Response Rate (ORR), Duration of Response (DoR), Disease Control Rate (DCR), and Safety.
The interim analysis of this study was conducted after a median follow-up of 8.7 months, from November 2022 to August 2023. The median PFS was significantly longer with Ivonescimab compared to Pembrolizumab. Patients receiving Ivonescimab had a median PFS of 11.14 months versus 5.82 months with Pembrolizumab. The Hazard Ratio (HR) was 0.51 (P<0.0001), indicating a 49% reduction in the risk of disease progression or death. The PFS benefit of Ivonescimab was consistent across various subgroups including histology, PD-L1 expression and metastatic sites. Ivonescimab demonstrated superior outcomes in ORR and DCR compared to Pembrolizumab with an ORR for Ivonescimab of 50%, compared to 38.5% for Pembrolizumab. The DCR was 89.9% with Ivonescimab and 70.5% with Pembrolizumab.
Both treatments showed similar safety profiles with no new safety signals for Ivonescimab. Treatment-Related Serious Adverse Events (TRSAEs) occurred in 20.8% of Ivonescimab-treated patients and 16.1% of Pembrolizumab-treated patients. Grade 3 or more immune-related Adverse Events (irAEs) were comparable: 7.1% with Ivonescimab and 8.0% with Pembrolizumab. Specifically, in patients with squamous cell carcinoma, TRSAEs were 18.9% with Ivonescimab and 18.7% with Pembrolizumab. Ivonescimab was associated with slightly higher rates of proteinuria and hypertension but overall demonstrated a manageable safety profile. Overall survival data and long-term safety data are awaited to confirm the clinical benefits of Ivonescimab.
In conclusion, the HARMONi-2 trial provided compelling evidence that Ivonescimab offers a statistically significant and clinically meaningful improvement in PFS compared to Pembrolizumab, in PD-L1 positive advanced NSCLC patients, with manageable safety profile. If subsequent data continue to support these findings, Ivonescimab may be a valuable alternative to existing therapies. One limitation is that the trial was conducted exclusively in China, which might affect the generalizability of the results to other populations.
Phase 3 study of ivonescimab (AK112) vs pembrolizumab as first-line treatment for PD-L1–positive advanced NSCLC: Primary analysis of HARMONi-2. Zhou C, Chen J, Wu L, et al. 2024 World Conference on Lung Cancer. Abstract PL02.04. Presented September 8, 2024. San Diego, CA.
