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Families of patents could face more double-patenting challenges

Cantor Colburn IP Newsletter February/March 2024

Can a patentee extend a patent term for the same invention by claiming a second patent for claims that aren’t “patentably distinct”? This is known as obviousness-type double patenting (ODP). The U.S. Court of Appeals for the Federal Circuit recently resolved a long-standing question about the interplay between ODP challenges and patent term adjustments (PTAs) granted by the U.S. Patent and Trademark Office (USPTO) because of delays in patent processing.

A threat to the family

Cellect owns a family of patents related to devices with image sensors that all claim priority from the same application. Four of the patents had different expiration dates because the USPTO granted each a PTA. Another patent that claimed priority from the application didn’t receive a PTA and expired 20 years after the application’s filing.

None of the patents were subject to “terminal disclaimer” during patent prosecution. With a terminal disclaimer, the patent applicant essentially agrees that the later patent’s term won’t extend beyond the earlier patent’s term.

ODP is based on the principle that an inventor can obtain only a single patent for an invention. An ODP determination depends on whether the claims of the later-expiring patent would’ve been obvious based on an earlier-expiring patent owned by the same party. If so, absent a terminal disclaimer, the later-expiring claims are invalid.

After Cellect sued Samsung for infringement, Samsung asked the USPTO to re-examine the four patents, arguing that the patents were unpatentable based on ODP. The patent examiner found the challenged claims in the four patents were obvious variants of expired reference patent claims.

Normally, a patentee can cure an ODP rejection by filing a terminal disclosure, but Cellect couldn’t do so because the reference patent had expired. As a result, the ODP rejections invalidated the four patents. The Patent Trial and Appeal Board (PTAB) affirmed, and Cellect appealed.

The extension question

Patent term extension (PTE) extends the overall patent term for a single invention because of regulatory delays in product approval (for example, during review by the U.S. Food and Drug Administration). Cellect argued that, because ODP doesn’t negate a validly obtained PTE, the PTAB should hold that ODP also can’t negate a PTA. The court has previously held that, when a patent has a PTE, the ODP expiration date is the expiration date before the PTE was added.

Cellect contended that unpatentability under ODP similarly should be determined based on the expiration dates of the patents before any PTA is added. Under this reasoning, if a later patent would’ve expired on or before the earlier patent’s expiration date in the absence of a PTA, the later patent can’t be invalid for ODP because it wouldn’t have impermissibly extended the earlier patent term.

The USPTO, however, asserted that PTA and PTE should be treated differently when determining whether claims are unpatentable under ODP. The Federal Circuit agreed, noting that PTA and PTE derive from different statutes and deal with different circumstances. While both are statutorily authorized extensions of a patent term, each has its own independent statutory framework.

According to the Federal Circuit, Congress intended that the filing of a terminal disclaimer in a patent subject to PTA would prevent any patent from being extended beyond the disclaimed expiration date. By contrast, the PTE statutory provision includes no reference to terminal disclaimers.

Allowing applicants to benefit from their failure to file a terminal disclaimer would frustrate Congress’s intent regarding PTAs. Thus, the court concluded that ODP for a patent that has a PTA must be based on the patent’s expiration date after the PTA has been added — regardless of whether a terminal disclaimer is required or has been filed.

Family matters

The court’s ruling is bad news for life sciences and other companies that commonly use continuation patents to protect families of patents. It leaves the owners of patents with PTAs more vulnerable to ODP challenges. Such patents now can be invalidated by earlier-expiring patents in the same patent family.

Sidebar:   Equity considerations are irrelevant

The U.S. Court of Appeals for the Federal Circuit also dismissed the patentee’s equitable arguments against an obviousness-type double patenting (ODP) rejection in Cellect. (See main article.) Cellect argued that the equitable concerns underlying ODP, including potential harassment by multiple patent assignees and improper patent term extension, didn’t exist here.

But the court found that, because the patents had expired less than six years earlier, the risk remained that multiple assignees would pursue past infringement damages. It rejected Cellect’s argument that Cellect had abrogated the risk of such harassment with its promise not to sell its expired patents.

The court also found that Cellect had indeed received unjustified extensions of patent term. The patent claims were obvious based on a patent that expired 20 years after filing, so any extension beyond that time was inappropriate. And Cellect’s good faith during patent prosecution didn’t entitle it to a patent term to which it wasn’t otherwise entitled. A patentee’s lack of “gamesmanship” in obtaining a patent term adjustment is insufficient to overcome a finding that the patentee received an unjust timewise term extension.

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