Broad functional patent claims are a hotbed of controversy. These claims to a group of materials are defined by their function, such as binding a biological target, rather than their chemical structure or sequence. Functional antibody claims are now before the US Supreme Court in Amgen v. Sanofi.
Functional antibody claims are broad and cover millions of potential antibodies that bind a target. When the patent discloses a few or none having the desired function, patent claims have been invalidated for not teaching which antibodies may have the desired function and how to make such antibodies.
Typically inventors do not try to obtain exclusivity over all small molecule drugs that bind and inhibit a particular target of interest. But some argue that biological materials, such as antibodies, should be treated differently, and that it is necessary to obtain exclusivity over all biological materials that bind to a target of interest, even after only discovering a few.
It is important to consider the impact on innovation of claims that attempt to control a therapeutic target and all biologic therapies to that target.
Controlling a Therapeutic Target
Patents with broad, functional claims to biological materials have generated significant controversy and litigation between innovators. The litigations, just as the case before the Supreme Court, involve patent claims to all antibodies that bind a particular therapeutic target and have a desired function although no or only a few antibodies have been discovered.
In these litigations, the broad functional claims cover the product of the patent infringement defendant, but the defendant’s product was independently invented. It is not described in the patent at issue and is unlike the few antibodies that are described.
These claims typically cause disputes with innovators, not with biosimilar makers. Biosimilar makers copy the commercial antibody described in the patent. As a result, patents with claims to the precise antibody are typically at issue in biosimilar litigation.
By contrast, functional genus claims come into play in battles between innovators. It is in this context that some stakeholders have argued that innovation will be deterred unless innovators can lay claim to a therapeutic area and exclude other innovators.
Concern Over Broad Functional Claims
Courts are skeptical of broad genus claims and have expressed concern about functional claims on innovation for over a century. In an 1895 case involving an incandescent lamp patent, the Supreme Court explained that broad claims extending well beyond the discovery that was made would discourage rather than promote invention.
They would discourage others from discovering materials with the claimed function. The court stressed that a limited discovery should not invest patentees with sovereignty over an entire kingdom or allow patentees to receive tribute for the brilliant discoveries made later by others.
The Federal Circuit, similarly, has expressed concern over functional claims that are far broader than what is enabled. It has struck down as invalid functional claims that cover millions of potential antibodies or other biologic therapies where the patents disclose none or only a few of the claimed antibodies.
The Federal Circuit pointed out for example that the claims in Amgen were doubly functional and required an antibody that binds to one or more of 16 specific amino acid residues, but that the patent disclosed no antibody that bound more than nine residues.
And the patent did not identify any antibody that bound three of the residues set forth in the claims. The Federal Circuit stressed that broad functional claims suppress innovation because a party can effectively gain control of what it has not invented and left for others to discover.
Lessons From Small Molecule Drugs
Although biological materials are more complex than small molecule drugs, the test for enablement is no different. Indeed, all inventions, regardless of technology, must be enabled. For enablement, courts are looking for innovators to set forth a chemical sequence or formula to allow artisans to make and use the claimed genus of biological materials or small molecule drugs.
While genus claims are common for small molecule drugs, the claims are generally not functional and do not seek to control all therapies to a biologic target. Rather, the claims are to structurally related chemicals defined by a structural formula: a structurally defined genus. For example, there are numerous statin drugs on the market that lower cholesterol by inhibiting HMG CoA reductase.
These drugs have different benefits and side effects, and some work for certain patients, while others do not. But while each of the statin drugs was or is protected by claims to their specific chemical structure or a genus of structurally-related compounds, the developers of these drugs did not control all small molecule drugs that inhibit HMG CoA reductase. That made a variety of treatments possible and spurred innovation.
There are numerous other small molecule examples, such as marketed HIV drugs. But, unlike with functional genus claims for biologics, the genus claims are to structurally related compounds, rather than all small molecules that inhibit a particular protein involved in HIV multiplication.
Small molecule drugs illustrate that control over a therapeutic target is not needed for pharmaceutical innovation. Indeed, if any one company controlled all inhibitors of HMG CoA reductase or of a protein that plays a role in the multiplication of HIV, that would suppress innovation and narrow options for patients.
This article does not necessarily reflect the opinion of Bloomberg Industry Group, Inc., the publisher of Bloomberg Law and Bloomberg Tax, or its owners.
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Irena Royzman is the head of life sciences at Kramer Levin Naftalis & Frankel, focusing on biotech and pharmaceutical patent litigation.