OREANDA-NEWS. The U.S. Food and Drug Administration's (FDA) recent guidance on labeling biosimilar products reduces one hurdle to growth of the nascent market for these drugs in the US, although many others remain, according to Fitch Ratings.

The market share of biosimilars should benefit from the labeling guidance because it allows the manufacturer to rely on the clinical data of the reference drug, which is similar to the labeling conventions of traditional small molecule drugs.

The FDA suggests that labeling should include a description of the clinical data that supported safety and efficacy of the reference product as described in the FDA-approved product labeling for the reference product. Additional clinical data should be included only when necessary to inform safe and effective use by a healthcare practitioner, according to the FDA.

While the guidance also requires biosimilar product-specific information on the label, Fitch views this as an obvious necessity as it provides prescribers with essential information on how to prescribe and use the biosimilar product.

The FDA has stated that biosimilar product labeling should not include a description of these data. This is so given that a clinical study supporting the licensure of the biosimilar product generally would not be designed to independently demonstrate the safety and efficacy of the product, but rather to support a demonstration that there are no clinically meaningful differences between the proposed biosimilar product and the reference product for the approved indication.

Stakeholders have yet to comment on the agency's guidance.

We believe several factors will likely drive the pace at which biosimilars gain market share. These include the number of biosimilars and the speed at which they successfully make it through the approval process; the success that biosimilars have in staving off patent infringement actions; price discount to reference biologic; whether the follow-on product is similar or interchangeable; third-party payers' strategies to move utilization to biosimilars from reference products; marketing and sales efforts of reference product and biosimilar manufacturers; and physician clinical preference and confidence in biosimilars.

Two biosimilars have been approved by the FDA: Pfizer's Inflectra was approved on Tuesday of this week and Novartis AG's Zarxio was approved last year.

That said, market dynamics remain uncertain. The ultimate market environment for biosimilars in the U.S. remains unclear given the uncertainties relating to a whole host of issues. Furthermore, pricing, physician acceptance, patient acceptance, ease of substitution and real-world clinical experience will help determine what the U.S. market eventually looks like. As such, Fitch expects it to evolve over time.

We believe the biosimilar market could eventually evolve to a point where it operates like the traditional small-molecule generic drug market. This transition requires technological advances to a level where biosimilar manufacturers can readily manufacture identical and interchangeable forms of the reference therapeutics. Interchangeable biosimilars would likely drive rapid conversion rates and steeper price discounts. However, as mentioned, Fitch believes most approved biosimilars will not be automatically interchangeable in the near term.