PTAB statistics show interesting trends for Orange Book and biologic patents in AIA proceedings

The Patent Trial and Appeal Board (“PTAB”) regularly tracks statistics regarding administrative trials conducted under the processes created by the America Invents Act (“AIA”), which provide insight into recent trends occurring at the United States Patent and Trademark Office (“USPTO”).  In addition to these routine statistics, the PTAB recently published the first update to its 2019 study of AIA trials involving petitions challenging Orange Book-listed patents and biologic patents through June 2021. Highlights of these pharmaceutical patent challenge statistics include, e.g., the number of these petitions filed, the number of instituted trials, and the trial outcomes since fiscal year 2013.[1]

The study update shows that the number of post-grant AIA challenges filed in the past 18 months has waned with respect to Orange Book-listed patents (“OB patents”) and biologic patents, and that the institution rates (e.g., 37% and 27% for OB patents, 42% and 33% for biologic patents in 2020 and 2021 year-to-date, respectively) for these patent groups have recently fallen far below the overall averages, which remain between 56% and 60% for the same periods.    

With respect to institution rates since September 2012, OB patents fall slightly below the average (62% for OB patents versus 64% for all utility patents), while biologic patents have the lowest chance of being instituted against (55%) out of all utility patents.  However, biologic patents tend to fare worse post-institution than OB patents in terms of overall invalidity rates.  Roughly 25% of all biologic patent petitions since September 2012 have resulted in all challenged claims being found unpatentable, compared to only 18% for OB patents. And only 9% of proceedings involving biologic patents have resulted in a determination that all claims are patentable, compared to 21% for those involving OB patents over the same period.  Of the biologic patent petitions that resulted in a final written decision, 70% found all claims unpatentable whereas only 21% found all claims to be patentable.  Meanwhile, for OB patents, only 45% of final written decisions resulted in all claims unpatentable and 50% resulted in all claims being held patentable.  These recent findings are consistent with PTAB data from 2019 showing that OB patents fared better than the overall averages while biologic patents tracked closer to the general trends.

These differences between OB and biologic patents may be due in part to the types of patents being challenged.  OB patents, which generally establish the scope of patents that Abbreviated New Drug Application (“ANDA”) filers must overcome on their way to launching a generic version of an Orange Book listed drug, cover only compound, formulation, and method claims. “Process patents, patents claiming packaging, patents claiming metabolites, and patents claiming intermediates” may not be listed in the Orange Book.  See 21 C.F.R. § 314.53(b).  In contrast, biologic patents, now listed in FDA’s Purple Book[2] and asserted in biosimilar litigation under the Biologics Price Competition and Innovation Act (“BPCIA”), encompass a broader range of patents and frequently include patents directed to manufacturing processes. The relatively higher OB patent success rate in AIA challenges may also be playing a role in the steadily decreasing number of OB patent AIA petitions per new ANDA submission, from just under 1 petition for every 4 ANDA submissions in 2015 to under 1 petition per 100 ANDA submissions projected in 2021.

When compared to all patents historically, both OB patents and biologic patents have been less likely to be instituted, with two exceptions.  In 2019, both OB patents and biologic patents were instituted at a higher rate than the average, and, in 2017, OB patent petitions alone had a higher than average institution rate.  Despite the generally lower likelihood of having a petition instituted, 2021 has seen a resurgence of petitions filed on biologic patents, bucking a downward trend since 2017 which saw only 8 biologic patent petitions in 2020, the lowest since 2014. So far, 23 biologic patent petitions have been filed in 2021 compared to only 5 OB patent petitions.  The biggest hurdle for biologic patent petitions appears to be getting past the institution phase – only one petition has instituted so far in 2021, and in 2020, more than half of all biologic patent petitions were denied.

The updated statistics show other trends unique to OB and biologic patents.  Since September 2012, both are far less likely to settle than overall proceedings.  Further, as discussed above, the institution rates have lowered recently compared to overall patents – since 2020, 60% or more of all OB and biologic patent petitions have been denied.  Finally, post-grant reviews (“PGRs”) are being filed as often, or more than ever before with respect to these patents.  Generally, PGRs represent fewer than 5% of overall petitions across all patents.  In 2020, OB patents and biologic patents had PGR petition rates of 3 to 5 times higher than the overall PGR petition rate, about 15% and 25%, respectively – a trend that has continued into 2021.  Although no PGRs were filed on biologic patents until 2017, the proportion of PGR petitions for biologic patents from 2017 forward has generally been higher than for OB patents each year.  The only exception to this trend in the proportion of PGRs among all AIA petitions is the projected 2021 rate, which is higher for OB patents at this time, likely due to the small sample size of 5 total OB patent petitions filed thus far.  Although PGR petitions still represent a minority of all petitions filed against OB and biologic patents, these trends suggest that more PGRs are on the way.

The approval of more biologics should also increase the overall number of PGRs, due to the availability of additional invalidity grounds that can be presented in those proceedings (e.g., Section 112 invalidity grounds).  Currently, FDA has approved 30 biosimilar products based on 10 reference products, and a number of companies, including Xbrane Biopharma, the teams of Biogen/Samsung Epsis and Teva/Bioeq, have announced their intention to file Biologics License Applications (“BLAs”) or abbreviated Biologics License Applications (“aBLAs”) for new reference biologics such as ranibizumab (Lucentis®). FDA also recently approved the first ever interchangeable biosimilar insulin product. The last BPCIA litigation on a previously unlitigated reference product was filed in 2018.  As more biosimilar applications are filed for new reference products, the rate of litigation and post-grant challenges involving biologic patents will likely see corresponding increases.

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