Adonertinib (FHND9041) versus Afatinib as First-line Treatment for Advanced Non-small-cell Lung Cancer with EGFR Sensitive Mutation (FHND9041-Ⅲ-01): A Multi-centre, Open-label, Randomised Phase 3 Trial

Technical Summary: Adonertinib vs. Afatinib in EGFR-Mutated Advanced NSCLC

Problem Statement
Advanced non-small-cell lung cancer (NSCLC) harboring epidermal growth factor receptor (EGFR) sensitive mutations is a prevalent driver of lung cancer mortality, particularly in Asian populations. While first-generation (e.g., gefitinib, erlotinib) and second-generation (e.g., afatinib) EGFR tyrosine kinase inhibitors (TKIs) have established efficacy, third-generation TKIs (e.g., osimertinib) have demonstrated superior progression-free survival (PFS) and central nervous system (CNS) activity compared to first-generation agents. However, the comparative efficacy and safety of third-generation versus second-generation EGFR-TKIs as a first-line treatment for this patient population remained unknown. Specifically, it was unclear whether a novel third-generation agent could offer a clinical advantage over the second-generation standard, afatinib, with a more manageable safety profile.

Methodology
The FHND9041-Ⅲ-01 study was a multi-centre, open-label, randomised phase 3 trial conducted across numerous institutions in China.

• Population: 346 patients with previously untreated, locally advanced or metastatic NSCLC harboring EGFR exon 19 deletion (Ex19del) or exon 21 p.Leu858Arg (L858R) mutations were enrolled between November 2021 and March 2023.
• Intervention: Patients were randomly assigned (1:1) to receive either adonertinib (FHND9041), a novel third-generation irreversible EGFR TKI, at 80 mg once daily, or afatinib at 40 mg once daily.
• Stratification: Randomization was stratified by EGFR mutation type (Ex19del vs. L858R) and the presence of brain metastasis (yes vs. no).
• Endpoints: The primary endpoint was progression-free survival (PFS) assessed by blinded independent central review (BICR). Secondary endpoints included objective response rate (ORR), duration of response (DoR), overall survival (OS), intracranial efficacy, and safety (treatment-emergent and treatment-related adverse events).
• Analysis: Efficacy was analyzed in the full analysis set (FAS) and per-protocol set (PPS). Safety was assessed in the safety set (patients receiving at least one dose). Statistical comparisons utilized stratified log-rank tests and Cox proportional-hazards models.

Key Results

• Progression-Free Survival (PFS): Adonertinib demonstrated a statistically significant improvement in median PFS compared to afatinib. The median PFS was 16.7 months (95% CI 14.5–20.8) for adonertinib versus 14.5 months (95% CI 12.5–16.5) for afatinib (Hazard Ratio [HR] 0.70, 95% CI 0.54–0.91; p=0.0087).
• Mutation Subgroup Analysis: The PFS benefit was primarily driven by patients with the EGFR Ex19del mutation. In this subgroup, median PFS was 26.1 months for adonertinib versus 16.5 months for afatinib (HR 0.53, 95% CI 0.36–0.77; p=0.0008). Conversely, no significant PFS benefit was observed for patients with the EGFR L858R mutation (11.2 months vs. 12.5 months; HR 0.86; p=0.4122).
• Overall Survival (OS): At the data cutoff (March 15, 2025), median OS was 35.2 months for adonertinib and 33.5 months for afatinib (HR 0.92; p=0.6259), showing no statistically significant difference. However, a trend toward OS benefit was noted in the Ex19del subgroup (HR 0.66; p=0.0915).
• Safety Profile: Adonertinib exhibited a more favorable safety profile regarding grade 3 or higher treatment-related adverse events (TRAEs). The incidence of ≥grade 3 TRAEs was 14.0% in the adonertinib group compared to 36.3% in the afatinib group. Specifically, adonertinib showed significantly lower rates of diarrhea (0% vs. 17.0%), rash (0% vs. 4.7%), and oral mucositis (0% vs. 3.5%) at grade 3 or higher. However, adonertinib was associated with higher rates of hematological toxicities, such as decreased platelets (24.4% vs. 4.1%).
• Intracranial Efficacy: Among patients with baseline brain metastases, intracranial PFS showed a trend favoring adonertinib (17.6 months vs. 14.5 months; HR 0.68), though this did not reach statistical significance (p=0.1565).

Significance and Claims
The authors claim that this study represents the first randomised phase 3 trial directly comparing a third-generation EGFR-TKI (adonertinib) with a second-generation agent (afatinib) in the first-line setting. The study concludes that adonertinib significantly improves PFS with a manageable safety profile compared to afatinib for patients with previously untreated advanced NSCLC harboring EGFR sensitive mutations.

The paper emphasizes that the efficacy benefit is particularly pronounced in the EGFR Ex19del subgroup, suggesting that adonertinib should be considered a new first-line treatment option for this specific population. The authors note that while overall survival data did not show a significant difference, the trend in the Ex19del subgroup warrants further observation. The study acknowledges limitations, including the enrollment of only Chinese patients and the need for further investigation into resistance mechanisms. The authors do not claim superiority over third-generation agents like osimertinib, nor do they propose immediate changes to guidelines for the L858R subgroup, where no significant benefit was observed.