1 April 2013AmericasJane Wainwright and Daniel Young

Post-grant patent challenges in Europe and the US: harmony at last?

Post-grant challenge in Europe

European Patent Office (EPO) opposition represents an important part of the toolbox for dealing with competitors’ patents. An opposition can knock out a competitor’s patent for a relatively low cost and can, in many European countries, even lead to a stay of parallel national infringement proceedings. Figures from the EPO also show that approximately two thirds of oppositions result in revocation or amendment of the opposed patent.

Despite the commercial advantages of filing an opposition, they are underused. Th e proportion of oppositions filed against granted patents in any given year is only around 5 percent (4.74 percent in 2011), with more life sciences patents being opposed than other technology areas such as electronics (7 percent for biotechnology compared to 2 percent in each of telecommunications and computer technology).

EPO opposition versus national litigation

A European patent, once granted, results in a bundle of separate national patents. Any challenge to the validity of a European patent via the court system must be made in each national court as a separate action. Undertaking multiple challenges, each in front of a different national court, can quickly become time-consuming and expensive. Courts in different countries can also come to different decisions, potentially resulting in a patent being valid in some European countries but not in others.


An EPO opposition, on the other hand, allows a centralised challenge to the validity of a European patent with the outcome applying to all of the separate national patents that resulted from grant of a European patent. A successful opposition resulting in invalidity cannot be challenged in a national court but, if an EPO opposition is unsuccessful, the opponent is still able to challenge validity nationally and the opposition ruling itself is not binding on any national court.

The centralised approach of an opposition reduces the amount of work that is required. There is no duplication of efforts by lawyers in multiple countries nor is there the need for multiple translations. Furthermore, the evidential requirements of the EPO are lower than those of a national court, with no discovery and only sporadic use of witnesses.

Due to these more streamlined procedures, the typical costs incurred during the whole opposition ($15,000 to $75,000) are lower than the cost of conducting a single national court action, and often significantly so.

Particular advantages for life sciences

Each opposition, irrespective of technology area, is decided on its own facts for each of the grounds of opposition that are raised. However, oppositions in the life sciences arena are often able to take advantage of the strict EPO practice in relation to lack of enablement, obviousness and unallowable amendment.

A common attack in the life sciences is that, due to the exemplification of the patent being limited to one or very few examples (eg, exemplification of only one antibody but claims directed to antibodies more broadly), the claimed invention does not solve the technical problem leading to both obviousness and enablement issues.

EPO oppositions are heard by an Opposition Division (OD) including two members who are technically qualified. As life science patents commonly involve complex scientific concepts and methods, the technical members of the OD oft en bring an insight that is not always possible during court proceedings.

Post-grant challenge in the US

In the US, validity of a patent may be challenged in a Federal court or before the Patent Trial and Appeal Board (PTAB) of the US Patent and Trademark Office (USPTO). The PTAB will review the challenge and decide whether the claims represent a bona fide invention or are unpatentable, in which case the rejected claims will be cancelled from the patent, or must be amended to be patentable.

The Leahy-Smith AIA

Under the America Invents Act (AIA), procedures were implemented to make postgrant challenge faster, expand the role of a third party challenger, and expand what grounds of invalidity can be re-considered by the PTO.

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