December 2019

Orange Book, Purple Book, Complex Products, and Process Patents

Philip E. Alford, Ph.D., MJLST Staffer

Complex Products and Process Claims

The most economically important pharmaceutical innovations of the past decade have centered around biologics and complex non-biologic products. Biologics are a diverse class of therapeutic products, typically produced via biotechnology or obtained from biological sources. Biologics often contain complex mixtures or large, elaborate molecules that are intricately folded into a specific desired conformation. In many respects, we do not yet have the technology to characterize all the functional elements of these products fully, and sometimes it is not possible to make the products synthetically or according to alternative processes. Even minor variations in biologic manufacturing can result in a product having different properties. Since the manufacturing process may be one of the most accurate ways to describe a biologic, patent strategies for biologics typically give extra emphasis around process patents. Indeed, biologic process claims have proven to be a powerful tool, and process patents have been at the core of the first waves of biosimilar litigation.

Non-biologic drugs can also be so complex as to defy characterization and reproduction. Such products are now referred to as complex products or non-biological complex drugs (NBCDs), as well as “nanomedicine” or “synthetic biologics.” Like biologics, many complex products have the challenge that different manufacturing processes can result in the product having divergent properties. Thus, manufacturing aspects are uniquely important to both complex products and biologics. Where the patent system is involved in the regulatory framework, process patents should play a central role in protecting complex products from generic entry. Yet for complex drug products, FDA does not integrate process patents into the generic entry process.

Despite being difficult to truly reproduce, complex products are nonetheless susceptible to market pressure under Hatch-Waxman-type generic entry 21 USC 355(b)(2) and 355(j), i.e., via Food Drug & Cosmetic Act 505(b)(2) and 505(j) applications. The Hatch-Waxman Act, discussed in more detail below, ingeniously incorporated the patent system as a secondary gatekeeper in FDA’s generic drug approval process. The so-called Orange Book is the nexus uniting two separate regulatory regimes. However, FDA has interpreted that the Orange Book and Hatch-Waxman provisions invoke only on the types of patents that were important for determining infringement of traditional, small molecule drugs, namely, drug and therapeutic use claims. The Orange Book expressly excludes process patents. 21 C.F.R. §314.53.

Although product-by-process claims can be permitted, the resulting product must be novel, and product-by-process claims are not interchangeable with process claims. (For example, see, MPEP 2113 and Judge Newman’s dissent in Abbott Labs. v. Sandoz, Inc, suggesting that process claims and product-by-process claims are held to different validity standards.)

Hatch-Waxman as a political bargain.

When Congress passed the Hatch-Waxman Act was passed in 1984, the Act represented a classic political bargain. The hope was to strike a balance between innovation and competition by strengthening the golden years of brand drugs while facilitating subsequent generic entry. Pioneers of approved new drugs were given up to 5 years of data exclusivity during which FDA would not approve a generic of the drug. Additionally, one of the pioneer’s patents could be extended up to 5 additional years to compensate for lost patent term consumed while seeking FDA approval. In turn, the Act provided a new, streamlined process for drug makers to obtain approval of generic drugs.

A key provision of the Act directs the drug pioneer to identify its patents in the Orange Book. The listed patents must (1) claim the new drug, or (2) claim a method of using the drug, in so far as a claim of infringement could reasonably be asserted if another engaged in the manufacture, use, or sale of the drug. 21 U.S.C. §355(b)(1)(G). The Orange Book thus represents an essential part of the Hatch-Waxman political bargain. Process (manufacturing) patents are expressly excluded from the Orange Book, as are patents relating to packaging, metabolites, or intermediates. 21 C.F.R. §314.53.

The Orange Book lists these patents alongside each FDA approved drug. Before obtaining approval of a generic, the generic drug maker must certify to FDA that the patents listed in the Orange Book are expired, invalid, or will not be infringed by its generic. 21 U.S.C. §355(b)(2)(A) and 21 U.S.C. 355(j)(2)(vii). Under 35 U.S.C. § 271(e)(2), such certifications of invalidity or non-infringement constitutes an act of infringement permitting the pioneer to sue the generic drug maker before the generic ever reaches the market. Prompt litigation can trigger a stay on the generic’s approval. In this manner, the Orange Book serves not only as a mechanism for transparency (informing the public of patent and regulatory exclusivities), but also as a mechanism for litigation. The Orange Book has served both causes well.

As blockbuster biologics began to approach the end of the foreseeable patent life, FDA created a compendium of BLA-approved biological products loosely mirroring the Orange Book, but for biologics instead of drugs. Reverently, FDA named this volume the Purple Book. Unlike the Orange Book, the Purple Book has had no reason to list patents because the generic drug provisions of the Hatch–Waxman Act apply only to drug approvals under 21 U.S.C. §355(b) and 21 U.S.C §355(j). The Biologics Price Competition and Innovation Act of 2009 (BPCIA) provides a framework for approving biosimilars and resolving patent disputes. Instead of referring to a book of approvals and patents, the BPCIA invokes a so-called patent dance exchange of patent information. 42 USC § 262 (l). This patent information includes not only composition and use claims, but also process of manufacture claims. Conceptually, the dance was expected to lead the parties to agree on an initial set of patents to litigate and thus control the tempo and scope of litigation. However, the parties soon recognized that dancing is optional. Sandoz Inc. v. Amgen Inc., 137 S. Ct. 1664. Dance or no dance, the parties ultimately litigate their patent disputes, which often center the methods of manufacturing the biologic product.

As new biologics and complex drug products come to market, process claims are likely to be increasingly important.

Possible Legislation to the Orange Book and Purple Book

This year, Congress considered legislation sponsored by members of the House Committee on Energy and Commerce proposing changes to the way the Purple Book and Orange Book function.

The Purple Book Continuity Act of 2019 proposes that the purple book be updated to list patents generated during the ‘patent dance’ of 42 USC § 262 (l), which would include process patents or any other patent likely to be important in an infringement claim. Any such patents listed in the Purple Book would not function as a regulatory gatekeeper for generics since no mechanism yet exists for the Purple Book to do so. Still, from a transparency point-of-view, it seems like a reasonable choice to have the Purple Book act at least as a compendium of relevant patents. The Orange Book Transparency Act of 2019 proposes a requirement to list the drug substance, drug product, and method of use patents, while also requiring removal of any patents that are improperly listed (presumably including process patents absent any change to 21 C.F.R. §314.53). Although the House Committee on Energy and Commerce sponsored both acts, each take differing approaches to process patents. It seems illogical to insert process patents into the Purple Book, while more tightly excluding process patents from the Orange Book at a time when process claims are increasingly more important to modern therapeutics.

Indeed, FDA has expressly focused on the manufacturing process when trying to understand how a generic relates to a reference complex product. For example, FDA explained that a central part of their inquiry was whether the generic is made according to the same process as the original®, a non-biologic complex product, FDA explained that a central part of their inquiry was whether the generic is made according to the same process as the original. See, also, Bell et al., which discusses FDA’s criteria for approving a generic even when there is no physicochemical or biological characterization technique to establish active ingredient sameness. If such an inquiry is part of FDA’s analysis for permitting the sale of a generic drug, then it should be more than enough to justify listing process patents in the orange book.

If Congress revisits either of these matters, it should adjust the code to include process patents in both the Orange Book and the Purple Book. Listing process patents in the Orange Book would serve a public good, namely, that of transparency, but also would notify competitors of the manufacturing space the pioneer drug company intends to protect. Delaying such litigation until after a possible generic approval is messy for all parties involved. As more medications become too complex to manufacture by alternative routes, the importance of process patents in complex biologic and nonbiologic drugs will only increase.