Prestige reports positive phase 3 topline data for Avastin biosimilar

CURRENT FULL VERSION: Prestige Biopharma has reported positive topline Phase 3 results for HD204, its proposed biosimilar to Avastin (bevacizumab), saying the SAMSON-II study met its primary endpoint in adults with advanced non-squamous non-small cell lung cancer. The company announced on March 24, 2026 that HD204 demonstrated clinical equivalence to Avastin on overall response rate at week 18, a key milestone for a program it has been advancing for several years. (prnewswire.com)

The result builds on a longer development path for HD204. Prestige’s earlier phase 1 SAMSON study, published in PLOS One in 2021, found pharmacokinetic equivalence between HD204 and both US- and EU-sourced bevacizumab in healthy male volunteers. Prestige had also signaled commercial ambition early: in 2022, it entered a commercialization and supply partnership with Intas Pharmaceuticals and its affiliate Accord Healthcare covering the US, Europe, Canada, parts of MENA, Latin America, South Africa, and several Asian markets. At that time, the company said US and EU filings were planned after Phase 3 development. (pubmed.ncbi.nlm.nih.gov)

According to Prestige’s latest announcement, SAMSON-II enrolled 625 patients at 91 centers in 15 countries in a randomized, double-blind, parallel-group design. Patients received either HD204 or Avastin with standard chemotherapy. The reported overall response rate at week 18 was 48.7% for HD204 and 46.5% for Avastin, with a risk ratio of 1.047 and a risk difference of 0.022; both confidence intervals stayed within the predefined equivalence range. Prestige also said secondary endpoints supported the primary analysis, with similar progression-free survival and overall survival and no statistically significant differences between arms. Treatment-related adverse events were reported in 33.9% of the HD204 group and 34.4% of the Avastin group, while treatment-related serious adverse events were 5.2% and 8.3%, respectively. No new safety signals were reported. (prnewswire.com)

The trial itself was already listed on ClinicalTrials.gov as a phase 3, randomized, double-blind equivalence study in metastatic or recurrent non-squamous NSCLC, comparing HD204 with EU-licensed Avastin and assessing efficacy, safety, pharmacokinetics, and immunogenicity. That registry context matters because biosimilar approvals typically rest on a totality-of-evidence framework, where analytical similarity and pharmacokinetic comparability do much of the scientific heavy lifting, and confirmatory clinical trials are designed to rule out meaningful differences rather than to show superiority. Prestige explicitly framed the SAMSON-II outcome that way in its announcement. That same regulatory logic is showing up across other biosimilar categories too: recent industry updates highlighted FDA approval of Teva’s denosumab biosimilar Ponlimsi for all Prolia indications, as well as FDA and EMA acceptance of Teva’s omalizumab biosimilar filings across all approved Xolair indications, both supported by analytical and clinical packages demonstrating comparable efficacy, safety, and immunogenicity to the reference products. (clinicaltrials.gov)

Industry context also favors products that can clear the final clinical and regulatory hurdles. US biosimilar markets have continued to mature, with oncology among the strongest categories for uptake. Recent market reporting has shown bevacizumab biosimilars achieving deep average selling price discounts relative to the reference product, and one Q1 2026 market report from Samsung Bioepis said biosimilars accounted for 92% of the bevacizumab market as of Q3 2025. At the same time, expert reviews in JAMA Oncology and trade coverage continue to point to persistent barriers, including reimbursement mechanics, education gaps, contracting, and payer behavior. The newer denosumab and omalizumab milestones also suggest that biosimilar momentum is not limited to oncology, but extends into bone health and immunology as regulators continue to accept broad indication packages built on comparability data. In other words, scientific success is necessary, but commercial success still depends on market access and channel strategy. (centerforbiosimilars.com)

Why it matters: For veterinary professionals, this is not a practice-changing animal health story, but it is a useful signal about the wider biologics market. Biosimilar development in human oncology keeps normalizing the idea that lower-cost biologic competition can be supported by rigorous comparability packages rather than repeated large efficacy programs in every setting. That has implications for how clinicians, hospital systems, and eventually adjacent health sectors think about evidence standards, supply resilience, and affordability. Broader biosimilar groups have argued that these products are already generating substantial healthcare savings, and global health organizations continue to frame biosimilars as a tool to expand access to essential biologic therapies. The recent Teva denosumab approval and omalizumab filing acceptances add to that picture by showing the same evidentiary model being applied across multiple therapeutic classes, not just oncology. (biosimilarscouncil.org)

There’s also a business angle worth watching. If HD204 reaches filing and approval, it would enter a bevacizumab market that is already crowded but still economically meaningful. Prestige’s existing partnership with Intas and Accord suggests the company has been preparing for commercialization well before this readout, which may help if regulators move efficiently. Still, the company has so far reported topline results rather than a peer-reviewed full dataset, so clinicians and market watchers will likely want to see fuller efficacy, safety, immunogenicity, and subgroup data before drawing stronger conclusions. At the same time, the pace of approvals and filing acceptances in adjacent biosimilar markets, including denosumab and omalizumab, will be a useful readout on how receptive regulators and commercial channels remain to new entrants. (businesswire.com)

What to watch: The next milestones are likely to be full data disclosure at a scientific meeting or in a journal, followed by any formal regulatory submissions in the US and Europe and, after that, updates from Prestige, Intas, and Accord on launch sequencing and market strategy. More broadly, continued approvals and filing progress in other biosimilar classes will help clarify whether the current momentum around totality-of-evidence reviews remains as strong as it appears. (prnewswire.com)