Oleksiy Mark /
19 December 2014AmericasChristine Goddard and Janis Fraser

Bulletproofing pharma patents

Bringing a single pharmaceutical drug product to market can be expensive. One estimate suggests that it requires an average outlay of more than $2.5 billion in research and development (R&D) expenses—and even then, there is no guarantee the drug will be a success.

Before undertaking such an enormous and risky investment, pharma companies need to have some assurance that they will be able to market a drug free of competition from generic copies long enough to provide a reasonable return on investment. In the US, the Hatch-Waxman statutory framework provides drugs with a basic period of protection from generic competition, but in most cases the three to five years of protection this provides is insufficient to deliver the needed incentive.

Generic companies assess the relative strength of a drug’s patent coverage when deciding which branded products to copy, and when. Weak patents invite attack, either in the courts or, with increasing frequency, in post-grant proceedings at the US Patent and Trademark Office (USPTO), with the intent of clearing the way for the generic company to enter the market. Therefore, maximising the strength of patent protection should be an important objective of any R&D pharma company. The creation of a ‘bulletproof’ patent—one that clearly covers the product, stands up to a validity challenge, and is enforceable against would-be competitors—necessarily involves careful strategy.

Tip 1: Know your enemy

Validity challenges are usually based on obviousness or lack of novelty in view of prior art. Knowing what prior art is out there when crafting the original application and claims permits the drafter to anticipate possible grounds for future rejections so that support for overcoming them, or avoiding them in the first place, can be built in.

Although a thorough prior art search at the time of drafting the application adds to the initial expense, it can streamline prosecution and, more importantly, result in claims that stand up to challenge after grant, so it’s money well spent.

Even the most thorough search normally cannot turn up so-called secret prior art—ie, a patent application that is on file but not yet published. Avoiding unnecessary delays in filing your patent application will help minimise the likelihood that, before your filing date, someone else has filed a relevant application that was undetected in your prior art search.

Another strategy is to describe numerous embodiments of the invention of varying scope in the application to provide support for amendments that might be needed during examination to carve around the prior art once it becomes known.

Tip 2: Embrace the narrow

The inclusion of narrow claims specifically directed to the expected commercial drug product or its approved uses is essential to a strong patent position. Many applicants instinctively seek the broadest scope possible to stop competitors from ‘designing around’ the claim by developing slightly different, competing products. While broad claims certainly can be useful in that respect, their breadth makes them more vulnerable to an invalidity challenge. A finding that any compound encompassed by the claim is not patentable will invalidate the whole claim.

Generally speaking, narrow claims specifically directed to the particular molecule that constitutes the drug product or the specific disease indication(s) for which the product will be marketed will present fewer vulnerabilities and result in a stronger patent position.

Of course, one can include both broad and narrow claims, along with claims of intermediate breadth—particularly if the ultimate product has not yet been selected or if there is a concern that competitors will be able to design around the narrowest claims.

Tip 3: It’s all in the details

When drafting the application, one may be tempted to skim over details of how to make and use the claimed drug product, either to gain a competitive advantage by hiding important details or simply to expedite the application drafting process. Skimping on such details is highly risky.

The claimed subject matter must meet the statutory ‘enablement’ requirement—ie, the supporting disclosure must teach both how to make the claimed compound and how to use it without the need for ‘undue experimentation’.

For claims covering small molecule drugs, a challenger may attack on ‘how to make’ enablement grounds if, for example, the description of the compound’s synthesis is so thin that it is difficult to reproduce the synthesis, or if it utilises starting materials that are not generally available.

A challenge on ‘how to use’ enablement grounds may occur if there is no reason to believe the claimed drug product actually has biological activity, or if the activity is not convincingly tied to the treatment of disease.

Also, US law still requires the specification to disclose what the applicant considers to be the “best mode” of practising the invention. Although recent changes in the law have taken the teeth out of that requirement by removing it as a ground for invalidity, it lurks in the US statute, with uncertain consequences for the applicant who ignores it.

Tip 4: Beware the data

Even a well-drafted patent with valid claims will be useless in litigation if the court finds the patent unenforceable because it was obtained as a result of a deliberate misrepresentation by the applicant to the USPTO. Although recent clarifications in the law have made unenforceability more difficult to prove, accused infringers still commonly raise the issue in litigation—if only as an excuse to paint the applicant as unscrupulous.

"The inclusion of narrow claims specifically directed to the expected commercial drug product or its approved uses is essential to a strong patent position."

It is therefore vital to be very careful when presenting data to the USPTO, either in the original specification or during examination. For example, if it appears that the applicant chose to reveal only selected data that supported patentability and suppressed other, contrary data, the court may determine that this constitutes a material misrepresentation that guts the patent.

To minimise this risk, applicants should carefully consider whether presentation of the data is truly necessary or can be dispensed with in favour of other, less risky strategies. Where the data are deemed essential for obtaining a patent, the applicant must ensure they are presented in the most unbiased way possible, keeping in mind that, when the data are submitted in the form of a declaration, the declarant (usually an inventor or other expert) will almost certainly be the target of a withering attack by the accused infringer during subsequent litigation on the patent. The challenger will probe the expertise and veracity of the declarant, looking for any possible argument that the latter committed fraud by misrepresenting something in the declaration.

Therefore, declarations should be avoided if possible, and, if they cannot be avoided, meticulous care should be taken regarding the accuracy and fairness of the statements made.

Tip 5: Duty to disclose—keep it simple

Another reason a court might find a patent unenforceable is if the applicant deliberately withheld material information (such as relevant prior art) from the USPTO during examination. In order to minimise this threat, all potentially material documents known to the applicant should be submitted to the USPTO before the patent is issued. This may sound straightforward, but the difficulties in complying with the duty of disclosure are numerous, and grow exponentially when there are a number of related, co-pending applications. Often there are several related patent applications filed around an important drug product, all pending at the same time.

Besides the primary application(s) claiming the drug product itself, including new salt forms or polymorphs, other applications might claim methods of making or using the product, while others may relate to different compounds that share a similar activity or structural element. Because each of these co-pending applications and their progeny relate in some way to the drug product, any reference cited, rejection made, or argument presented in these cases should be reviewed with an eye to whether it might be material to patentability of the claims of any other application in the group, and so should be cited to the examiner handling the other application.

Where there are many co-pending, related applications, this reviewing and cross-citing can be a complex, arduous task requiring substantial resources, and always with a risk that something potentially material will be accidently omitted in a given case. Consideration should therefore be given to minimising the number of related co-pending cases in active prosecution, utilising strategies such as delaying examination of relatively unimportant cases and foreign counterparts, prosecuting progeny applications (continuations and divisionals) serially rather than in parallel, and abandoning applications with little commercial or competitive value.

Tip 6: Round up rogue rights

On the face of it an obvious problem to avoid, the uncovering of problems regarding ownership of patents that protect existing commercial products or products under development is surprisingly common.

Ownership of patent rights initially vests with the inventor(s), so one should make an accurate inventorship determination before filing an application and then seek assignments from each of the inventors either before or shortly after the filing date. Inventors may leave the company and become difficult to locate and/or uncooperative, so delays in obtaining those assignments runs the risk of greatly complicating the process. All employees who are involved with research or other activities that may result in inventing should be required to execute an agreement assigning all future inventions to their employer as a condition of employment.

Likewise, consulting agreements, joint research agreements, and contracts with outside entities such as clinical research organisations should make it clear that inventions made under the contract either belong to the company that will be marketing the drug, or will be exclusively licensed to that company.

The nightmare scenario is where an individual who did not assign and has no obligation to assign to the company is later deemed by a court to be an inventor. If that individual licenses or assigns his/her rights to a competitor, the patent cannot be asserted against the latter. Identifying that individual as a co-inventor early in the process, long before the patent issues and the product is on the market, will allow the company developing the drug to lock in an assignment from the individual before potential competitors wake up to the opportunity.

The above discussion highlights only a few of the many important factors to consider when building a strong pharma patent. In practice, the process is complex and continuous, requiring periodic and strategic evaluation from drafting to issuance. Only such diligence can position an important patent as close as possible to the bulletproof ideal that will not only help the patent survive future challenges, but also reduce the likelihood it will be challenged in the first place.

Janis Fraser is a principal at Fish & Richardson. She can be contacted at:

Christine Goddard is a principal at Fish & Richardson. She can be contacted at:

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