Comparative Preclinical Evaluation of Tuznue Versus Referent Herceptin: A Registered Trastuzumab Biosimilar

The high cost of trastuzumab (Herceptin^®) limits its accessibility for patients worldwide. Biosimilars, such as Tuznue^® (HD201), represent a promising alternative to improve access to this essential therapy for HER2-positive breast cancer. This study aims to assess the similarity of Tuznue^® with the reference product Herceptin^® through comprehensive analytical and biofunctional evaluations, ensuring similar quality, safety, and efficacy profiles.

Multiple analytical methods were performed to assess key quality attributes of Tuznue^® and Herceptin^®. Physicochemical properties, HER2 binding, anti-proliferative activity, antibody-dependent cellular cytotoxicity, complement dependent cytotoxicity, and Fc receptor binding were evaluated through various bioassays. Statistical analyses were conducted according to a risk-based tiered approach (Tiers 1-3) to demonstrate biosimilarity. The equivalence margin for critical quality attributes (Tier 1) was set at ±1.5 standard deviations from the reference product's mean.

Tuznue^® showed highly comparable results to Herceptin^® across all evaluated biofunctional assays. HER2 binding affinity, inhibition of cellular proliferation, and antibody-dependent cellular cytotoxicity activity were equivalent between Tuznue^® and Herceptin^®, with 90% confidence intervals within predefined equivalence margins. No complement dependent cytotoxicity activity was observed for either product. Differences in glycosylation profiles were identified but did not affect critical biofunctional properties. Fc receptor binding remained consistent across all tested lots.

The comprehensive analytical characterization confirms the biosimilarity of Tuznue^® to Herceptin^®. This supports Tuznue^® as a safe and effective alternative, offering a more affordable option for patients and healthcare systems. Biosimilar development requires overcoming inherent challenges, particularly when reference products exhibit variability in quality attributes over time. Regulatory guidance and scientific rigor are essential to ensuring biosimilar similarity, facilitating broader patient access to life-saving therapies.