Patent Term Restoration – Denied!

In 1984, Congress amended the Patent Act to permit a patent extension for certain types of inventions — many (but not all) of those subject to premarket testing and federal government approval requirements.  Some people call this patent term extension; others call it patent term restoration.  Between enactment of the statute in September 1984 and the end of March 2017, the Patent and Trademark Office received 1113 applications for patent term extensions in connection with new drugs and biological products.  But by April 1, 2018, it had granted only 664 extensions.  Why do companies not get patent term extension?  Usually because this wasn’t FDA’s first approval of the active ingredient. 

More after the jump.


In 1984, as part of the Hatch-Waxman Amendments, Congress amended the Patent Act to require that PTO extend the term of patents protecting some products that go through regulatory review.  Federal law requires these patent owners to obtain government approval to market their inventions, and it also requires them to perform research (safety testing and in some cases also effectiveness testing) before applying for approval.  This research and regulatory review eats up some of the patent term, so Congress provided for an automatic extension of the patent term.  The patent owners get back some, but not all, of the time eaten up.  This is why some people call it patent term restoration.

Eligible products: new drugs, biological products (for humans), new animal drugs, veterinary biological products, medical devices, food additives, and color additives. USDA approves veterinary biologics; FDA approves the other products.  But only certain of these products (certain new drugs, certain medical devices) are eligible for patent term extension. 

Eligible patents: a patent that claims the product, a method of using the product, or a method of manufacturing the product.  PTO will extend only one patent per regulatory review, though, which ends up being one patent per marketing application — one per new drug application (NDA) or biologics license application (BLA) — and only if certain additional requirements are met.

The eligibility and additional requirements, and the rules for calculating the extension, are complex.  They have also evolved over the last 30 years, further complicating study of the scheme.  Even the way PTO does the math has changed.  And the statutory provisions have been amended. More details below, as relevant.

My Data

I started with a spreadsheet, provided by PTO, of all patent term extension applications received through March 31, 2017.  I separated out the new drugs and biologics.  (PTO’s spreadsheet labels them, but some of the labels are incorrect.) In the paragraphs below, I just use the terms “drug” to refer to both.

I gathered information about each drug, about FDA’s approval decision, about the patent proposed for extension, about the extension decision itself, and about the life cycle of the patent and the drug.  I now have 65 data elements for each patent term extension request. Kristina Acri and I are working on a detailed statistical analysis of the patent term extension grants.  We hope to have something to share in the spring.

Today I am focusing on the non-grants.

PTO Disposition of Patent Term Extension Applications

During my study window, PTO received 1113 applications for patent term extension connected to regulatory review of a drug.  

Even though there were 1113 patent term extension applications, there were only 894 drugs at issue.  Why?

For each new drug application or biologics license application, PTO may extend one patent.  But PTO allows a company to propose several patents for extension at the same time and then choose which to extend, once FDA and PTO are done with the applications.  (Both agencies play a role in processing the applications.)  Once you delete all of the “parallel” applications from the data set, there are only 894 discrete drugs.** (** but see my caveat at the end)

Of the 894 drugs associated with patent term extension applications, how many got extensions?

Granted:  664PTO has granted patent term extensions for 655 drugs.  Another 9 drugs enjoyed “interim” extensions, while PTO was reviewing their requests, that ended up totaling what they would have received anyway.  I count those as extensions granted, which gives me 664 grants. 

Pending: 108.  Another 108 drugs had patent term extension requests still pending when I stopped collecting data. 

That leaves 122.  For these, the outcomes are a bit mixed — some were withdrawn, some were denied, some were dismissed, and so forth.

So, why didn’t the 122 drugs get patent term extensions?

Answering this requires a closer look at the PTO and FDA materials and often other sources as well.

Not first commercial marketing: 80.  PTO must deny patent term extension if FDA has previously approved the active ingredient (or its salt or ester) pursuant to another application filed under the same FDA approval provision.  (This seems like a simple rule, but it’s not. There have been disputes and litigation, as well as changes in how PTO interprets the rule.) Eighty drugs were denied patent term extension because the FDA approval in question did not represent the first permitted commercial marketing of the active ingredient.  (Four of those would have been denied for other reasons as well — three because the extension request was not timely filed, and one because the patent did not claim the approved product or a use of the product).

Drug never approved: 13.  Thirteen drugs proposed for patent term extension were never approved by FDA — drugs like atamestane, lixivaptan, mifamurtide, and vapreotide.  You can apply for patent term extension before FDA approves your marketing application, so long as FDA has accepted the application, and there are interim extensions available if the FDA approval process would extend past patent expiry.  (These just keep the patent alive until your product is approved.)  None of these 13 drugs was ever approved, and some were actually not even the subject of marketing applications.  (The companies that submitted those PTR requests shouldn’t have done so.)

Not timely filed: 4.  The patent owner must submit its request for extension within 60 days of FDA approval. (This sounds like a simple rule, but it’s not. It has resulted in litigation twice, as well as statutory changes, beyond the scope of this blog post.)  Four drugs were denied patent term extension because the applications were filed after the deadline.

Patent did not claim the product: 3.  Another three drugs were denied patent extension (or the request was dismissed) because the patent did not claim the product or its use, or because PTO asked the applicant to explain how the patent claimed the product/use, and the applicant failed to do so.

Patent invalidated: 2.  Another two were denied because the patent was invalidated.

Applicant did not explain relationship to NDA/BLA holder: 3 PTO takes the position that, to be eligible for patent term extension, the patent owner or its agent must have undertaken the activities that led to regulatory approval.  In another 3 cases, the person requesting patent term extension did not explain its relationship to the NDA/BLA holder.

Effective patent life already exceeded 14 years: 5.  The effective patent life after patent term extension may not exceed 14 years.   Put another way, the expiry date of the restored patent must be no later than the 14–year anniversary of FDA’s approval of the NDA/BLA.  Another 5 were not entitled to patent term extension because the effective patent life already exceeded 14 years.

That leaves 12 for which I don’t have definitive answers. 

  • I believe that four of drugs approvals were not the first commercial marketing of the active ingredient. 
  • I notice that another two had data exclusivity slated to expire after the patent would have expired even with the extension.  (This data exclusivity prevented submission of generic applications at FDA.)  Neither drug received the extension, and one request was actually withdrawn.  It’s possible the companies decided it wasn’t worth pursuing extension further, because the data exclusivity expired later. Or there could be another explanation; I cannot tell.
  • The other six were withdrawn by the applicants for reasons that were not stated.

What’s the bottom line?

Most drugs for which patent term extension requests were filed (74%) enjoyed a patent term extension. Roughly 9 percent of the time, though, the company was not eligible for a patent extension, because this wasn’t the first time FDA had approved an NDA or BLA for the active ingredient.

*Caveat:restoring one patent for each NDA/BLA does not mean restoring one patent for each new active ingredient.  FDA sometimes requires companies to submit separate applications at the same time for a single new active ingredient.   If FDA approves the applications on the same day, PTO will extend a patent with respect to each application. There are a handful of new active ingredients in the data set that had two patents extended.

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