Ever since the Federal Circuit held that a later-issuing but earlier-expiring patent could serve as an obviousness-type double patenting (OTDP) reference in Gilead Sciences, Inc. v Natco Pharma Ltd., 753 F.3d 1208 (Fed. Cir. 2011), Applicants and Patentees have found themselves facing many more double patenting rejections. Even continuing applications filed in a single portfolio run the risk of receiving OTDP rejections if the claims of the subject and reference patents are not patentably distinct. See AbbVie Inc. v. Kennedy Inst. of Rheumatology, 764 F.3d 1366 (Fed. Cir. 2014). The court in Kennedy explained (in dicta) that patents sharing a common priority chain “still can have different patent terms due to examination delays at the PTO.” AbbVie, 764 F.3d at 1373. So, patent term adjustment accumulated during examination could be in jeopardy when the subject claims overlap those in a continuation.

With patent term adjustment in the Federal Circuit’s crosshairs, divisional applications and their safe harbor protection against double patenting rejections under 35 U.S.C. § 121 have assumed a sudden new importance. Generally speaking, the Federal Circuit has allowed divisional applications to avoid OTDP rejections in most scenarios, as long as the subject application was formally labeled a divisional and the claims that issued were consonant with those withdrawn from an earlier case pursuant to a restriction requirement. But a recent Patent Trial and Appeal Board (PTAB) decision has called even the limited protection for divisional applications into question when intervening continuations are thrown into the mix. Ex Parte Sauerberg, Appeal 2015-007064 (PTAB Jan. 10, 2017).

Background on Obviousness-Type Double Patenting and the Safe Harbor Provision

35 U.S.C. § 121 provides statutory protection from double patenting rejections for a divisional application filed as a result of a restriction requirement:

A patent issuing on an application with respect to which a requirement for restriction under this section has been made, or on an application filed as a result of such a requirement, shall not be used as a reference either in the Patent and Trademark Office or in the courts against a divisional application or against the original application or any patent issued on either of them, if the divisional application is filed before the issuance of the patent on the other application.

The Federal Circuit has repeatedly addressed the scope of this “safe harbor” protection against OTDP, explaining that a reference patent must comply with certain formality and substantive features in order to qualify for protection. First, the reference patent must be labeled a divisional and not a continuation or continuation-in-part. Pfizer, Inc. v. Teva Pharm. USA, Inc., 518 F.3d 1353 (Fed. Cir. 2008); Amgen Inc. v. Hoffman-La Roche Ltd, 580 F.3d 1340 (Fed. Cir. 2009). An applicant must claim divisional status during examination and generally cannot correct this later by reissue. G.D. Searle LLC v. Lupin Pharm., Inc. 790 F.3d 1349 (Fed. Cir. 2015). In addition to formally identifying a patent as a divisional, the issued claims must also be consonant with an independent and distinct invention withdrawn from the parent application pursuant to a restriction requirement. Geneva Pharms., Inc. v. Glaxosmithkline Plc, 349 F.3d 1373 (Fed. Cir. 2003). Protection can be lost if intervening cases present inconsistent claims or receive irreconcilable restriction requirements. Bristol-Myers Squibb Co. v. Pharmachemie B.V., 361 F.3d 1343 (Fed. Cir. 2004).

In general, the Federal Circuit has tended to treat patentees leniently when they introduced nuances but otherwise complied with the formal and substantive requirements mentioned above. For instance, the court has explained that applicants need not immediately cover all inventions restricted out of a parent case in one single divisional. Rather, an applicant may file a series of divisional applications directed to different inventive groups identified in an original restriction requirement while retaining safe harbor protection. Boehringer Ingelheim Int’l. GmbH v. Barr Labs., Inc., 592 F.3d 1340 (Fed. Cir. 2010). Likewise, the court has explained that continuations descending from divisional applications can retain safe harbor protection over the original parent case that received the restriction requirement. Symbol Techs., Inc. v. Opticon, Inc., 935 F.2d 1569 (Fed. Cir. 1991); see also Amgen Inc. v. F. Hoffman-La Roche Ltd, 580 F.3d 1340 (Fed. Cir. 2009).

PTAB Decision in Ex Parte Sauerberg

Given this trend in the case law, the Sauerberg applicants must have felt fairly confident in their safe harbor eligibility when they filed a “divisional” application after a series of continuations of an original application that received a restriction requirement. After all, the Federal Circuit had previously confirmed that a subject patent could retain protection even when separated from the case that received an original restriction requirement by a chain of intervening divisional applications. The court had even extended protection to continuations filed from those divisional applications. But despite this body of precedent, the PTAB held in Sauerberg that a divisional filed from a continuation (rather than a divisional filed from another divisional, or a continuation filed from a divisional) was an entirely different scenario and denied safe harbor protection.

As background, in 2008 Sauerberg et al. filed a patent application directed to a genus of small molecule compounds and methods of treatment using those compounds (“original application”). In response to a restriction requirement between those two groups, the applicants elected the compound claims. The applicants serially filed two subsequent continuations (CON-1 and CON-2) with further compound claims, and then finally filed a divisional from the second continuation with claims directed to methods of treatment. The original application, CON-1, and CON-2 all issued as patents. The examiner rejected the divisional for double patenting over all three earlier patents and the applicants appealed.

On appeal, the PTAB first addressed the two continuations. While agreeing that “there is no requirement under § 121 that the divisional application being shielded by the safe harbor must immediately follow the parent,” the Board explained that safe harbor only applied when the reference patents at issue were filed “as a result of a restriction requirement.” Because the applicants could not show that they filed the two continuations in response to a requirement from the examiner to restrict the claims, safe harbor did not apply. The Board did not explain how they reconciled their holding with the protection extended by the Federal Circuit to continuations filed from divisional applications.

Turning to the original application, the Board pointed to the Federal Circuit’s instructions in Lupin to narrowly apply the safe harbor provisions using a “strict test” (albeit in a different context involving reissue of a CIP application to switch its designation to a divisional). Based on that “strict test” and a narrow reading of § 121, the Board concluded that a divisional application must be filed before the original application that received a restriction requirement grants, rather than at any time during the pendency of an application that claims priority back to that original application. Thus, the Sauerberg applicants missed their window of opportunity to rely on safe harbor protection because the divisional application was filed from CON-2, long after the original application had issued as a patent.

It remains an open question whether the PTAB’s interpretation of § 121 will withstand Federal Circuit scrutiny. Nevertheless, in light of the decision, it would be prudent for applicants to file at least one divisional during the pendency of any application that receives a restriction requirement in order to preserve the opportunity to argue for safe harbor protection.