A Clear Patent Term Extension Provision: A Must in Any Biosimilars Legislation

April 13, 2009 New Jersey Law Journal

© 2009 New Jersey Law Journal

With Democrats now controlling the legislative agenda in Washington, the debate over a federal regulatory approval pathway for biosimilars or follow-on-biologics (“biosimilars”) seems inevitably leading to major amendments to the Public Health Service Act, Food, Drug and Cosmetic Act and the Patent Act. A central issue in this debate turns on the extent of market exclusivity. Advocates for the generic industry will argue for limited exclusivity, while the innovator companies will push for legislation effectively extending the life cycle of their branded biologicals. Aside from attempts to propose a legislation which parallels the current abbreviated pathway for the small molecules, the innovator biopharma companies must secure patent term provisions that would allow effective extension of their patents directed to the manufacturing process of their novel therapeutic biologics.

Reviewing the evolution of patent term extension jurisprudence sets the stage for an intense debate as to the boundaries of any patent term extension provision on any biosimilars legislation. The patent term authority in the current version of 35 U.S.C. Section 156 finds its origin in the Drug Price Competition and Patent Term Restoration Act of 1984 (“the Hatch-Waxman Act”), codified under 35 U.S.C. Section 156. The Hatch-Waxman Act was intended to strike a balance of incentives for the first entrants of pioneer small molecule drugs and the first entrants of generic drug makers on the market. The Hatch-Waxman Act allows the owner of an approved pharmaceutical drug product to recover a portion of the time lost from the patent term which is spent during the regulatory review period regarding the patented drug product. However, the Hatch-Waxman Act did not amend the Public Health Service Act, under which therapeutic biologics are approved. Therefore, currently there is no abbreviated pathway for the approval of therapeutic biologics.

As any biosimilars pathway must address the immunogenicity, safety and efficacy issues for the biosimilars, it is prudent for the innovative company to establish a strategy to maximize the term of their manufacturing patents for any such products. Such strategy should begin early at the legislative stages. Perhaps the most important negotiation for any patent authority in a biosimilars legislation should concern authorization of patent term extension for manufacturing process claims, the scope of exclusivity granted to such process claims and the listing of such patents in the Approved Drug Products and Therapeutic Equivalence (“Orange Book”) or the like publications for therapeutic biologics. Currently, under 35 U.S.C. Section 156, patent claims directed to a method of manufactured (i.e., the process for producing a product) are eligible for term extension, even though they are not listed in the Orange Book.

Prior proposed bills for biosimilars in Congress gave cursory attention to the topic of patent term extension and its importance to brand-named therapeutic biologics. The new legislation, however, needs to address the eligibility and scope of the right extended to any brand-named therapeutic biologics and offer viable life cycle strategies to the patent holders. During the therapeutic biologics approval process, the process of manufacturing a candidate product is subject to intense scrutiny by the Food ans Drug Administration (“FDA”). The processes of perfecting these procedures are important assets for innovator companies in maintaining their competitive edge. Thus, aside from the availability of patent term extensions for the actual approved biologic product, any legislation covering federal regulatory approval for biosimilars should clearly allow for a patent term extension for a method of manufacturing the approved product.

The examination of the legislative history of the Hatch-Waxman Act shows that Congress was primarily concerned with the extension of the patent term for both product and method of use claims. During the Hatch-Waxman debate, there were two essential requirements for eligibility of such method claims for patent term extension. First, there should have been no other product claim or methods of use claim covering the approved product. Second, the patent must claim the manufacturing method of the approved product. Effective life cycle strategies demand that the brand-named therapeutic biologics should reserve their term extensions for the most valuable patent in the patent portfolio covering the approved product.

As any new biosimilars law would likely amend Section 156, a clear guideline as to the eligibility and scope of the right extended is paramount. The current state of the law and the evolution of patent term extension jurisprudence have been to some degree unpredictable. In light of this unpredictable state of the law, Congress must take a proactive role in defining not only the eligibility criteria of any patent term extension, but also the scope of any such extension offered. Further, avenues to extend method of manufacturing claims by innovators should be viewed anew as a tool to extend the lifecycle of products.

The ambiguity in current patent term extension jurisprudence is over the scope of the terms” approved product” and its “active ingredient.” This confusion finds its roots in the divergent interpretation of the term active ingredient by the United States Patent and Trademark Office (“USPTO”) and the Food and Drug Administration (“FDA”). Both the USPTO and FDA examine the terms in view of their statutory definitions, creating a disconnect as to what is the active ingredient and how it is claimed in its respective product patents.

The right to extend the term of a U.S. patent reciting one or more claims covering an FDA-approved product centers on exactly what moiety the FDA and USPTO determine as the “active ingredient” contained in the approved product. Once the “active ingredient” is identified, the scope of the right extended is limited to the approved use of the active ingredient, its salts and its esters.

Given that a structural variability may exist between specific innovative and biosimilar therapeutic products and the direct correlation to the way such products are manufactured — such as for example, glycosylation or phospohorylation variability, determining the scope of the right extended in product patent claims can be difficult to ascertain. The process of determining the scope of the right extended for a patent claim covering an FDA-approved product begins with interpretation of the term “product” within the current statute. The Court of Appeals for the Federal Circuit holdings provides guidance as to the scope of the term “product” for satisfying the eligibility criteria of disputed approved products.

For example, the Federal Circuit has taken an expansive position for defining “Product” in the statute and allowed extension of the patent term for new salts and esters of a previously approved “active ingredient” in Glaxo Operations UK Limited v. Donald Quigg, 894, F.2d 392, 395, 397 (Fed Cir. 1990). Even though this interpretation suggests eligibility of the improved biologic products for a patent term extension, a recent Federal Circuit decision doesn’t clarify the issue. The Federal Circuit also held that the scope of patent term protection was extended to other variations of the approved active moiety that was not ultimately the subject of an approved marketing application. Pfizer, Inc. vs. Dr. Reddy’s Laboratories, LTD, 359 F.3d 1361 (Fed Cir 2004). Even further, in a recent decision issued on September 12, 2007, by the commissioner’s office, the USPTO denied an application for patent term extension for U.S. Patent No. 6,143,772 submitted by AstraZeneca covering Nexium® IV. In this decision, the USPTO defined the term “active ingredient” to mean “active moiety.” Relying on the definition used in Pfizer, the USPTO first declared Glaxo overruled and then realizing its error, declared their definition of the term to be consistent with the ruling in Glaxo.

In light of such ambiguities, there is a need that early discussion on the scope of any patent right extended be clearly explored during the legislative debate. In addition, innovator companies must save strategies to maximize life cycle of their biologic products by pushing for clear amendments to Section 156 that also call for extending process of manufacture patent claims.