Secret Springing Prior Art and Joint Research: Lessons from Merck v. Hopewell

by Dennis Crouch

The Federal Circuit’s recent decision in Merck Serono S.A. v. Hopewell Pharma Ventures, Inc. provides important clarification on when a patent reference qualifies as prior art “by another” under pre-AIA law 35 U.S.C. § 102(e).  It also highlights ways that the AIA has subtly changed this category of “secret springing prior art” that is now codified under § 102(a)(2) and the special exceptions found in § 102(b)(2) and §102(c).

The case comes as we also have a pending Supreme Court petition in Lynk Labs challenging whether this secret prior art qualifies as a “printed publication” that can serve as the foundation for an inter partes review (IPR) challenge.  That petition is set for consideration by the Court later this week.

Background on Merck Serano v. Hopewell: Back in 2002-2004, IVAX and Serano (now Merck Serano) began collaborating on developing an oral cladribine treatment for multiple sclerosis.  Scientists at the companies met and exchanged confidential information about dosing regimens. In March 2004, IVAX employees filed a patent application (the “Bodor reference”) naming only IVAX employees as inventors. A few months later in December 2004, Serono filed patent applications (which matured into the patents-in-suit) naming only Serono employees as inventors. Although the two applications claimed different inventions, they contained overlapping disclosure regarding specific dosing regimens.

The question in the case is whether the earlier filed Bodor reference qualifies as prior art under the secret prior art provisions of pre-AIA 35 U.S.C. § 102(e). The critical question was whether Bodor qualified as a disclosure “by another” when the two companies had been collaborating and sharing confidential information, or whether the overlapping disclosure should be treated as Serono’s “own work” that cannot serve as prior art.

Secret Springing Prior Art has a unique backdating feature.  A patent application filed with the USPTO is not immediately prior art upon filing and instead remains secret for some time. However, once that application is later published or issued as a patent, it springs into existence as prior art. The trick is that the reference’s effective prior art date is backdated to its original filing date, not its publication date. In other words, an application that no one could have known about can suddenly invalidate later-filed patents as if it had been public all along – hence my term “secret springing prior art.”  Although there is no requirement of overlapping claims, most policy justifications of the statute focus on preserving the integrity of the priority system and preventing undeserved monopolies.

Section 102(e) has a key caveat relevant to this case: a prior filed application is only prior art if its “by another.”  Pre-AIA it was clear that this “another” meant different inventors (the system was not so applicant focused as it is today). Here, Bodor was filed first and so once published became 102(e) prior art against Serono’s application, and thus could be used for both anticipation and obviousness.  The appeal focuses on whether the collaboration between the two groups could be used dance around the prior art.

The typical approach to by-another analysis begins with looking at whether there are overlapping inventors between the prior art and the challenged patent.  If (as here) there is no overlap, we assume that the invention was by-another — but, the patentee can still avoid the prior art by showing the relevant portion of the disclosure reflects the collective work of the same inventive entity identified in the patent.

Merck argued that despite the lack of overlapping names, the six-line disclosure in Bodor actually reflected the inventive work of one or more of Merck’s named inventors – making it not “by another” even though De Luca wasn’t listed as an inventor on the Bodor application. Merck contended that during the Serono-IVAX collaboration, Merck’s inventors contributed the key dosing regimen ideas that appeared in Bodor, and therefore the disclosure should be treated as the work of Merck’s inventors (or at least a subset of them).

In the appeal, the Federal Circuit rejected Merck’s arguments – primarily holding that Merck had failed to provide evidence proving its factual claim.  The Board found insufficient corroborated evidence that De Luca or any other Merck inventor contributed inventively to the six-line disclosure, and the Federal Circuit held this factual finding was supported by substantial evidence.

The Federal Circuit also explained that an invention is “by another” whenever there is any difference in inventorship – i.e., under 102(e), the prior art is “by another” unless there is complete identity of inventorship.  This qualification addressed  was decided by the the Federal Circuit’s predecessor court (the CCPA) in In re Land, 368 F.2d 866 (CCPA 1966).

In Land, joint inventors Edwin Land and Howard Rogers of Polaroid fame filed a patent application together on February 13, 1956, for a photographic color process. The Patent Office rejected their joint application as obvious over a combination of references that included two earlier-filed patents: one issued solely to Land (with a priority date of August 9, 1954) and one issued solely to Rogers (with priority dates of March 9, 1954, and June 29, 1955). The applicants argued these individual patents shouldn’t count as prior art because they disclosed the joint inventors’ “own knowledge and disclosures, just as much as if the earlier filed sole applications had been joint applications.” The CCPA disagreed with their broad argument, recognizing that A is a different inventive entity from A&B, and B is a different inventive entity from A&B.

However, the Land court recognized an important qualification: when individual inventors later collaborate, they might describe their joint invention in an earlier solo application, and in that situation, the earlier disclosure wouldn’t be “by another.” But the burden was on the applicants to prove it, and in Land itself there was no indication that the portions of Land’s and Rogers’s individual patents disclosed anything they had done jointly, or any showing that what they did jointly was done before filing the individual patent applications, so those individual patents remained valid prior art. The Merck court affirmed this principle again in 2025 with a consistent rule:

Under pre-AIA § 102(e),  excluding a prior art reference as not “by another” requires the patentee to prove that the specific portions of the reference relied upon for unpatentability were invented by the identical inventive entity as named in the challenged patent claims.

The Merck Court then emphasized: “Any incongruity in the inventive entity between the inventors of a prior reference and the inventors of a patent claim renders the prior disclosure ‘by another,’ regardless of whether inventors are subtracted from or added to the patent.”  And, the patentee failed to provide that evidence.

What about that joint inventorship agreement.  

It’s worth noting that the invention in Merck occurred before Congress enacted the CREATE Act of 2004 creating 35 U.S.C. § 103(c) (and later expanded it in the AIA § 102(c)). This provision was specifically designed to address situations like Merck – where collaborating parties working under a joint research agreement might otherwise have their work used against each other as prior art in an obviousness rejection. Section 103(c) provides that subject matter developed by another person that qualifies as prior art only under § 102(e), (f), or (g) “shall not preclude patentability under this section where the subject matter and the claimed invention were, at the time the claimed invention was made, owned by the same person or subject to an obligation of assignment to the same person” or were made pursuant to a joint research agreement. Had this provision been available to Merck, the company might have been able to invoke the joint research agreement with IVAX to disqualify Bodor as prior art for the obviousness rejection – though it still would have needed to prove that De Luca or the other Serono inventors actually contributed to the specific six-line disclosure to avoid the anticipation issue. The AIA now includes expanded protections in § 102(b)(2)(C) and § 102(c) that also apply to knock out anticipation references.

How the AIA Changes Everything

While Merck v. Hopewell clarifies pre-AIA law, the America Invents Act fundamentally restructured the “by another” analysis in ways that would likely produce a different outcome if this case arose under current law.

There are two ways that the AIA modestly expands the scope of secret springing prior art.  Most relevant to the discussion above is replacement of the “by another” clause with “names another inventor.”  This language shifts the entire focus on the express listing of inventors on the prior patent application — literally asking if those inventors different than those listed on the challenged patent. The second aspect of the 102(a)(2) change is that it now focuses on only filing dates, the patentee can no longer “swear behind” the reference by proving a prior invention date.

However, post-AIA § 102(b)(2) provides several important exceptions that particularly support corporate endeavors like those in Merck.

Prior Disclosure Obtained from Joint Inventor (§ 102(b)(2)(A)): This provision disqualifies secret prior art if “the subject matter disclosed was obtained directly or indirectly from … a joint inventor” of the claimed invention. This exception appears to overrule aspects of Land. In Land, individual patents by Land and by Rogers were held to be § 102(e) prior art against a joint patent by Land and Rogers, even though each individual inventor’s disclosure was their “own work.” Under post-AIA § 102(b)(2)(A), if the subject matter in such an individual patent was “obtained directly or indirectly” from the joint inventors, it would be disqualified as prior art.

Applied to Merck v. Hopewell, if Bodor or Dandiker had “obtained” the six-line disclosure “directly or indirectly” from De Luca, Ythier, Munafo, or Lopez-Bresnahan (the Merck inventors), the Bodor reference would be disqualified from serving as prior art.  This exception would not have saved Merck on the actual facts of this case. The Board found insufficient evidence that the specific six-line disclosure was obtained from any of Merck’s named inventors.

Common Ownership and Joint Research Agreements (§ 102(b)(2)(C)): This provision represents the most significant change for collaborative innovation. It disqualifies prior art when “the subject matter disclosed and the claimed invention, not later than the effective filing date of the claimed invention, were owned by the same person or subject to an obligation of assignment to the same person” or were developed under a joint research agreement.

This exception provides broad protection for corporate collaborations. If Merck and IVAX had structured their 2002 research agreement to qualify as a “joint research agreement” under the statutory definition in post-AIA § 102(c), the Bodor reference would be disqualified as prior art entirely – regardless of who actually invented the disclosure or who obtained it from whom.  The AIA’s version of this law expands upon the 2004 Cooperative Research and Technology Enhancement (CREATE) Act.  Notably, CREATE only permitted co-ownership and joint research to overcome § 103 obviousness prior art; the 2011 AIA extended this protection to § 102 anticipatory prior art.

It is not clear to me that the particular agreement between the parties would have satisfied the statutory requirements for JRA protection.  However, sophisticated parties today absolutely would structure their collaboration agreements to qualify for this exception. The benefits are important – all secret springing prior art generated during the collaboration by either party (or by their joint work) would be disqualified against patents claiming inventions developed under the agreement. This provides certainty and removes the need for complex inventorship disputes like the one in Merck v. Hopewell.

Prior Public Disclosure (§ 102(b)(2)(B)): This provision disqualifies secret prior art if “the subject matter disclosed had, before such disclosure, been publicly disclosed by the inventor or a joint inventor or another who obtained the subject matter disclosed directly or indirectly from the inventor or a joint inventor.”

This exception would not have helped Merck because it requires that the inventor publicly disclosed the subject matter before the secret filing. In Merck v. Hopewell, the key dispute involved Bodor’s March 2004 filing (which published in October 2004), and there was no evidence that Merck’s inventors publicly disclosed the specific six-line dosing regimen before that date.

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While Merck v. Hopewell clarifies pre-AIA law, in my opinion the real story is how dramatically the AIA has reshaped the landscape for collaborative innovation in ways that better align patent law with modern research and development practices. These principles may soon face fresh scrutiny as the Supreme Court considers the Lynk Labs petition on whether secret prior art qualifies as a ‘printed publication’ for IPR purposes.