Why this could stall the only on-label alternative to compounded Avastin for wet AMD

Outlook Therapeutics has confirmed receipt of a second complete response letter from the U.S. Food and Drug Administration regarding the biologics license application for ONS-5010/LYTENAVA (bevacizumab-vikg), a proposed ophthalmic formulation of bevacizumab for wet age-related macular degeneration. The company disclosed that despite submitting new mechanistic and natural history data, the U.S. Food and Drug Administration maintained its earlier position, stating that the application lacked adequate confirmatory evidence to support approval. Notably, the regulatory agency did not indicate what type of evidence would satisfy its threshold for approval

Why FDA uncertainty may be more damaging than outright rejection

For Outlook Therapeutics, the rejection is not simply a delay but a signal that the U.S. Food and Drug Administration remains fundamentally unconvinced by the current clinical package. The lack of specificity in the complete response letter effectively blocks the regulatory path forward, offering neither a definitive endpoint nor a clear remediation strategy. This places Outlook Therapeutics in regulatory limbo at a time when the company was positioning ONS-5010 as a market-disrupting, on-label alternative to off-label compounded Avastin in ophthalmology.

The absence of guidance on what would constitute acceptable confirmatory data is particularly problematic. The company’s clinical strategy has largely been built around the NORSE TWO pivotal trial, which met its efficacy endpoints in a well-controlled setting. Outlook Therapeutics also included supportive safety and efficacy data from additional NORSE studies such as NORSE EIGHT, a non-inferiority study comparing ONS-5010 to ranibizumab. However, the U.S. Food and Drug Administration’s continued insistence on further evidence—despite recognizing that one pivotal trial demonstrated efficacy—raises the possibility that the agency is looking for broader validation, potentially through a second full-scale trial.

How ONS-5010 differs from traditional biosimilars or repackaged Avastin

Unlike traditional biosimilars that are approved based on analytical comparability and limited bridging studies, ONS-5010 is formulated specifically for intravitreal use. The product is not a copy of an oncology-indicated bevacizumab being repurposed through compounding, but rather a dedicated ophthalmic formulation developed under current good manufacturing practices. This places it outside the typical biosimilar regulatory track, making it subject to a full BLA review and requiring adequate and well-controlled efficacy trials.

Outlook Therapeutics’ strategy was to offer a U.S.-manufactured, single-dose vial formulation of bevacizumab for intravitreal injection that could serve as an FDA-approved, quality-assured alternative to the compounded versions of Avastin widely used off-label in the treatment of wet age-related macular degeneration. However, this pathway has now been disrupted for a second time, and the clinical strategy that underpinned the resubmission appears insufficient to meet evolving regulatory expectations.

The divergence between U.S. and European regulators is now hard to ignore

In contrast to the setback in the United States, Outlook Therapeutics has made significant commercial and regulatory headway in Europe. The company has already secured Marketing Authorization for LYTENAVA (bevacizumab gamma) from the European Commission and the Medicines and Healthcare products Regulatory Agency in the United Kingdom. The product became commercially available in Germany and the UK in mid-2025 for the treatment of wet age-related macular degeneration.

This regulatory divergence underscores a growing disparity in evidentiary standards and approval thresholds between the U.S. Food and Drug Administration and its European counterparts. While European agencies accepted the NORSE clinical package—including the pivotal NORSE TWO trial and supportive data from NORSE EIGHT—as sufficient, the U.S. Food and Drug Administration continues to find the same dataset lacking. This presents an unusual regulatory asymmetry, especially for a product targeting a highly standardized therapeutic space such as anti-vascular endothelial growth factor therapies for retinal disease.

Why compounded Avastin still dominates the U.S. anti-VEGF market

The broader context of this regulatory impasse is the continued dominance of compounded Avastin in the United States. Despite lacking formal approval for ocular indications, Avastin remains widely used intravitreally due to its affordability and comparable efficacy in real-world settings. Multiple compounding pharmacies supply single-dose formulations repackaged from the systemic oncology drug, with a relatively strong safety record when handled by high-quality providers.

This entrenched use of off-label Avastin presents a significant challenge to the commercial viability of any new entrant, particularly one priced at a premium to compounded versions. Outlook Therapeutics had positioned ONS-5010 as a safer, more consistent, and regulator-approved product that could replace this gray-market supply chain. However, without formal approval, that positioning cannot be operationalized, and the product’s core value proposition remains hypothetical.

Why NORSE TWO alone may not be enough to change the game

The pivotal NORSE TWO trial was designed as an adequate and well-controlled study that met its efficacy endpoints, and Outlook Therapeutics has repeatedly pointed to this trial as the foundation of its regulatory submission. The company supplemented NORSE TWO with other trials such as NORSE SEVEN and NORSE EIGHT, the latter of which was a non-inferiority study comparing ONS-5010 to ranibizumab over a short 12-week treatment window.

However, industry analysts suggest that the U.S. Food and Drug Administration may be viewing the dataset as insufficiently replicated or lacking the kind of confirmatory trial typically expected in a new BLA. If the agency is applying a standard more aligned with innovator drugs rather than biosimilar-like formulations, then a second pivotal trial may be unavoidable.

That raises questions about the feasibility of mounting a new trial, particularly under current financial constraints. It also puts pressure on Outlook Therapeutics to extract more real-world evidence from its European launches that could potentially be used in a future resubmission or negotiation with regulators.

Strategic options narrow unless clarity emerges from the U.S. Food and Drug Administration

Outlook Therapeutics has indicated it is evaluating all available options to pursue approval in the United States. This could include a Type A meeting with the U.S. Food and Drug Administration to obtain clarification on what additional evidence is needed. The company may also explore a Special Protocol Assessment to lock in a mutually agreed trial design if it chooses to conduct another efficacy study.

Yet these pathways all require time, capital, and execution risk. Meanwhile, the company’s ability to drive commercial success in Europe will be closely watched. Outlook Therapeutics has already launched LYTENAVA in Germany and the UK and is actively pursuing market access and partnerships across additional European markets. However, achieving significant market penetration will require more than regulatory approval; pricing, reimbursement, and adoption dynamics will be critical.

The commercial success of LYTENAVA in Europe could serve as both a revenue driver and a credibility booster, potentially offering real-world data that might influence future U.S. regulatory decisions. But without clear timelines and measurable outcomes, the firm’s position remains precarious.

Why this decision may influence future reformulated biologics in ophthalmology

The implications of the U.S. Food and Drug Administration’s stance extend beyond Outlook Therapeutics. Other companies exploring reformulated or alternative dosing formats of established biologics may now view the regulatory path as less predictable. The agency’s expectation for confirmatory evidence—beyond even one adequate and well-controlled trial—suggests a rigorous bar for reformulated monoclonal antibodies intended for intravitreal use.

This could affect strategic planning for a host of pipeline programs that fall into the gray zone between biosimilars and new biologics. With fewer margin advantages and higher development costs, companies may reconsider how to approach ophthalmology assets that do not offer transformative efficacy or dosing innovation.

Financial and clinical clocks are now ticking for Outlook Therapeutics

Time is now a critical factor. Without a clear regulatory path in the United States, the addressable market shrinks dramatically. The wet age-related macular degeneration treatment space is highly competitive, dominated by agents such as aflibercept and faricimab, both of which have gained traction due to longer dosing intervals and better durability data.

Outlook Therapeutics must either secure a defined pathway forward with the U.S. Food and Drug Administration or double down on maximizing its position in Europe. If neither generates meaningful returns or strategic optionality in the near term, the company could face tough decisions regarding capital allocation, additional trials, or even asset monetization.

  bevacizumab gamma, bevacizumab-vikg, FDA CRL, LYTENAVA, NORSE TWO, ONS-5010, ophthalmic biologics, Outlook Therapeutics, retina, wet AMD