Under the common interest doctrine, separately represented clients can avoid the normal waiver implications of disclosing privileged communications to third parties. Unfortunately, some courts do not recognize the doctrine, and most courts take a very narrow view – requiring that the common interest participants be in or anticipate litigation.
But some courts take an expansive view. In In re Intuniv Antitrust Litigation, Civ. A. Nos. 16-cv-12653-ADB (Direct) & 16-cv-12396-ADB (Indirect), 2018 U.S. Dist. LEXIS 207545 (D. Mass. Dec. 10, 2018), the court held that two companies considering a merger could rely on the common interest doctrine to safely share privileged communications about patent litigation involving one of the participants. Interestingly, the court did not point to the work product doctrine – which clearly would have covered the "litigation summar[ies]" the merging companies shared, and which would have survived such disclosure to a friendly third party. One day later, the court in AgroFresh Inc. v. Essentiv LLC, Civ. A. No. 16-662-MN-SRF, 2018 U.S. Dist. LEXIS 213204 (D. Del. Dec. 11, 2018), similarly held that a patent licensor and an exclusive licensee shared a common interest. The adversary argued that a patent licensee's interest is not "truly identical" to a licensor's interest, because "the licensee is free from the obligation to pay royalties on sales of the product if the patent is invalidated." Id. at *14. The court relied on earlier decisions in explaining that "licensors and exclusive licensees of patent rights are understood to share an identical legal interest in obtaining strong and enforceable patents." Id.
Expansive cases like this frequently generate hope that other courts will expand the common interest doctrine to transactional settings. But few courts have moved in that direction.