Does Size Matter? Nanoscale Particle Size as an Indicator of Inherency in Nanopharmaceutical Patent Validity

• Publication year: 2022

Does Size Matter? Nanoscale Particle Size as an Indicator of Inherency in Nanopharmaceutical Patent Validity

Kirsten Fehlan
kfehlan1@student.gsu.edu

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DOES SIZE MATTER? NANOSCALE PARTICLE SIZE AS AN INDICATOR OF INHERENCY IN NANOPHARMACEUTICAL PATENT VALIDITY

Kirsten E. Fehlan^*

Abstract

Scientific and technological advances in nanopharmaceuticals bring the doctrine of inherent obviousness to a head. On the one hand, nanotechnology promises to offer novel ways to target and treat traditionally incurable diseases by operating at a scale that is comparable to the scales that most biological systems use. On the other hand, nanotechnology inventions that result in improved pharmacokinetic properties are susceptible to validity challenges based on inherent obviousness.

Inherency and obviousness are two independently recognized and well-understood principles in United States patent law. Inherency refers to a claimed limitation or feature that is either necessarily present in, or the natural result of, the features expressly disclosed by the prior art. Obviousness, in contrast, refers to whether the claimed invention as a whole was readily apparent in the prior art based on a combination of references. Because inherency turns on whether something was necessarily present in the prior art at some earlier time, the analysis implicates hindsight. But because obviousness turns on

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what would have been obvious to a person having ordinary skill in the art at the time the invention was made, the analysis forbids hindsight.

Despite the seemingly mutual exclusivity between inherency and obviousness, the two principles have been increasingly applied together in the context of pharmaceutical and biotechnology inventions. Patent challengers frequently rely on the argument that improved pharmaceutical concentration and bioavailability at the target site is implicit in prior art teachings concerning how pharmaceutical particles behave at decreased sizes despite the novelty of the particle's size alone. Rather than engage in an arbitrary analysis focusing on how unexpected some pharmacokinetic response is, courts and the USPTO should eradicate the concept of inherent obviousness in its entirety.

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CONTENTS

Abstract..............................................................................1057

Introduction.......................................................................1060

I. Background....................................................................1063

A. Vehicles of Drug Delivery: How Do Nanopharmaceuticals Even Work?..........................1065
B. A "Small" Introduction to Nanopharmaceuticals ... 1067
C. A Non-Technical Primer on Inherency....................1069
D. The Current Nanopharmaceutical Landscape........1074

II. Analysis.........................................................................1075

A. A Hint at Inherent Microparticles in the Context of a Composition Claim ................................................... 1075
B. Par Pharmaceutical, Inc. v. Twi Pharmaceuticals, Inc.: The Test for Inherent Properties of Nanopharmaceuticals but Not the Answer...............1080
D. Inherent Obviousness After Par Pharmaceutical.....1088

III. Proposal.......................................................................1089

A. Eliminating the Concept of Inherency in the Context of an Obviousness Analysis in Courts and at the USPTO .... ..................................................................................1090
B. Tools to Use Instead of Inherent Obviousness.........1093

1. Inherent Anticipation..........................................1093
2. Plain Old Obviousness.......................................1094

Conclusion..........................................................................1095

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Introduction

Within the last thirty years, nanotechnology has emerged as a viable approach to overcome historically insurmountable technological deficits apparent in a variety of traditional scientific applications.¹ Nanotechnology refers to the design, production, or modification of structures, devices, or systems at the nanoscale (2 Recently, nanotechnology has been used to investigate how structures engineered with nanomaterials interact with biological systems, like the human body.³ Accordingly, nanotechnology, when applied as clinical nanomedicine, offers a promising approach for treating, diagnosing, or preventing historically untreatable diseases through the design and development of pharmaceutical nanoparticles (nanopharmaceuticals) to drive targeted drug delivery.⁴ When compared to conventional drug delivery, nanoparticle-mediated drug delivery increases pharmaceutical concentrations in targeted cells relative to non-targeted cells, thereby decreasing symptoms of unfavorable side effects associated with the administered drug.⁵ That said, nanotechnology's promising impact in clinical medicine collides with patentability challenges at the commercialization stage, where the process of converting basic nanopharmaceutical research into commercially viable products has been "difficult."⁶ Despite this

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difficulty, however, viable commercialization depends on securing valid patent protection first.⁷

Patent law—one of the "most obscure legal disciplines"—sits on the front line of modern drug development.⁸ To be patentable, an invention must be novel as well as useful, nonobvious, and compliant with patentability statutory requirements.⁹ This fundamental principle of patent law favors patent validity unless the claimed invention covers unpatentable subject matter or has been previously disclosed by one or more prior art references.¹⁰ Prior art references, however, need not disclose every limitation of the claimed invention.¹¹ Rather, prior art that fails to explicitly disclose the claimed invention nevertheless precludes patentability when a feature of the claimed invention

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necessarily flows from the prior art.¹² Nanopharmaceuticals present a unique patentability challenge because a decrease in particle size significantly impacts the compound's molecular properties, like biologic distribution (or biodistribution); however, whether the resultant molecular properties necessarily flow from the larger version of that compound remains unclear.¹³ Yet with no clear direction from the Federal Circuit, pharmaceutical companies and research institutions are left wondering whether modifying particle size at the nanoscale renders inherent the biological effects resulting from a decrease in size.¹⁴

Companies either seeking a nanotechnology patent or attempting to enforce a nanotechnology patent share a common problem: patent uncertainty.¹⁵ One obstacle to enforcing nanotechnology and nanopharmaceutical patents, in general, concerns whether a claimed limitation of a nanoparticle composition necessarily flows from, or is inherently present in, the prior art.¹⁶ Although courts generally agree that properties resulting from a decrease in particle size are inherent, at a minimum, courts should cautiously apply the inherency doctrine when evaluating the validity of nanopharmaceutical patents.

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This Note proceeds in the following three parts. First, Part I provides a general introduction to the structure and function of nanopharmaceuticals and the law governing their patentability.¹⁷ Second, Part II investigates and analyzes the current state of U.S. case law concerning nanopharmaceutical patent challenges based on inherency.¹⁸ Finally, Part III proposes that courts should rethink the inherency standard as it applies to nanopharmaceutical patents—or eliminate it altogether.¹⁹

I. Background

Nanotechnology is "the design, characterization, production and application of structures, devices and systems" by modifying shape and size of matter at the nanoscale.²⁰ Because nanotechnology simply refers to manipulating matter on an atomic, molecular, or supramolecular scale, the application of nanotechnology within each respective scientific field is equally diverse.²¹ Accordingly, nanotechnology defined by size encompasses a naturally broad range of scientific fields and disciplines, including molecular biology, surface science, electrical engineering, semiconductor physics, and more.²² One application of nanotechnology—namely, nanomedicine—refers to the medical application of nanotechnology.²³

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Nanomedicine encompasses a broad application of nanotechnology via the design and development of nanomaterials, biological devices, nanoelectric biosensors, and biological machines.²⁴ Recent trends in experimental nanomedicine have focused on examining the interaction between nanomaterials and biological systems, thereby paving the way for novel developments in targeted drug delivery through nanoparticles.²⁵

The "unique" and "far-ranging properties" attributed to nanoparticles have already facilitated major breakthroughs in the pharmaceutical industry, which raked in $16 billion on nanomedicine sales in 2015 alone.²⁶ But success comes at a high price. Because of the high-risk, high-reward nature of the pharmaceutical industry—which is characterized by exceedingly high research and development (R&D) costs, lengthy clinical trials and data generation periods, and intense competition among pharmaceutical market participants—patents are a key ingredient for commercial success due to their promise for market exclusivity.²⁷

The possibility for commercial success with nanopharmaceutical and nanoparticle-mediated drug delivery systems inspired an influx of patent applications at the United States Patent and Trademark Office

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(USPTO) that continues in full force to date.²⁸ Rather than succumb to this influx of nanopharmaceutical patent applications, however, the USPTO did exactly as it does: It granted patents.²⁹ With no formal classification system to fully encompass novel nanotechnologies, the USPTO granted overly broad patent claims.³⁰ Broad...