Are antibody inventions patent-eligible?
Therapeutic antibody drugs are some of the most difficult and expensive drugs to develop but, at the same time, they may be the only drugs which can cure or substantially extend the life of patients with fatal or debilitating diseases. Payoffs to a drug company for a successful therapeutic antibody can be huge, with the yearly patient costs for treatment often being in hundreds of thousands of dollars.
In recent years, patent ineligibility issues under 35 USC §101 with regard to antibody inventions have grown significantly. In the US, laws of natural products, natural phenomenon, and abstract ideas are not patent-eligible. This article will explore whether antibody products and antibody diagnostic methods are patent-eligible.
Legal standard on patent eligibility
In 2012, in Mayo v Prometheus, the Supreme Court held that a method claim concerning optimising therapeutic efficacy for treatment of an immune-mediated gastrointestinal disorder was not patent-eligible. The Supreme Court concluded that the correlation between the toxicity and effectiveness of the drug and the amount of drug was a natural law. Thus, the invention was directed to patent-ineligible subject matter. This case came as a shock to many in the IP and pharma worlds, since these claims had been considered patentable for many years.
The next year, in Association for Molecular Pathology v Myriad, the Supreme Court held that a claim that encompassed naturally occurring DNA could not be rendered patentable merely by adding the word “isolated” to the claim. The court also clarified that cDNA (which is not a naturally occurring form of DNA) was patent-eligible.
Immediately after these decisions, significant uncertainty regarding the proper application of the new heightened standards of patent-eligible subject matter to different antibody fact patterns led to significant disparity between examiners at the US Patent and Trademark Office (USPTO) with regard to patent eligibility of antibody claims. The USPTO issued “Patent Eligibility Guidance” in 2014, 2015 and 2016 to attempt to standardise examination across the examining corps and to provide clarity on the USPTO position.
According to the USPTO, when deciding whether a claim is patent-eligible, at step 1 an applicant asks whether the claim is directed to a process, machine, manufacture or composition. If yes, the applicant proceeds to the next step. If not, the claim is patent-ineligible. In the next step, step 2A, the applicant asks if the claim is directed to a law of nature, natural phenomenon, or abstract idea. If not, then the claim is eligible. If yes, the applicant proceeds to step 2B, and asks whether the claim recites additional elements which amount to significantly more than the judicial exception. The process flow chart is displayed in Figure 1 (see page 56).
Following the USPTO guidance, a critical question is step 2A: is the claimed invention directed to a law of nature or natural phenomenon? A nature-based product is not “directed to” a law of nature or a natural phenomenon if it has markedly different characteristics.
As to markedly different characteristics, three points should be kept in mind: 1) the markedly different characteristics analysis should be applied to a combination, rather than component parts; 2) the characteristics are compared to the component in its natural state; and 3) markedly different characteristics can be expressed as product structure, function, or other properties.
New antibodies
At this point in time, it is generally accepted that a claim directed broadly to a new “purified or isolated human antibody” is not patent-eligible, if humans had previously been exposed to the antigen to which the new antibody binds. There are simply no structural or functional differences from the antibody previously existing in humans. This conclusion is a logical extension of the Myriad case, which held that a claim to an “isolated” natural product is not patent-eligible (see 2014 USPTO Nature Based Product Examples, Example 8, Claim 1).
However, what if the sequence of the claimed antibody is specified in the patent claim? Strictly speaking, an old antibody does not become patent-eligible just because it was isolated and characterised to determine its sequence. But, technically, the burden on showing that the sequence occurs naturally is on the challenging party.
It is not typically possible for a patent challenger to show an exact antibody sequence previously existed in humans. Thus, presenting amino acid sequence information in a patent claim may present an insurmountable hurdle for a patent challenger to prove that the claim encompasses natural, pre-existing antibodies.
Another situation surrounds chimeric antibodies. If the antibody is “chimeric” (usually part human and part mouse), the antibody is not a natural product, and is patent-eligible.
Antibody ‘compositions’
In patent parlance, an antibody “composition” is usually considered to include an antibody and at least one additional component. Merely specifying that an antibody composition includes an antibody and a “pharmaceutically acceptable carrier” (which could include water, saline solution, etc) may not be enough to meet the “significantly more” test. Also, natural antibodies, if they exist, would be present in human blood and tissues, which include many other natural components, such as water, salt, etc.
