## Facts

- Diamedix Corporation owned two patents covering immunoassay systems for testing blood for hepatitis virus and had granted multiple nonexclusive licenses before 1988.
- In 1988, Diamedix granted Abbott Laboratories a worldwide license to make, use, and sell patented products that was exclusive as to Abbott and its affiliates, but subject to prior licenses.
- Diamedix retained significant rights, including rights to make and use patented products and to sell to specified customers (including prior licensees and certain other categories), and the agreement was not assignable without mutual consent.
- The agreement gave Abbott the primary right to sue for infringement; if Abbott declined, Diamedix could sue. The party bringing suit controlled the litigation, and Abbott could not settle in a way that would prejudice or impair Diamedix’s patent rights.
- Abbott sued Ortho Diagnostic Systems, Inc. for infringement without joining Diamedix as a co-plaintiff.
- Diamedix moved to intervene as of right under Federal Rule of Civil Procedure 24(a)(2); the district court denied the motion, finding Abbott adequately represented Diamedix’s interests.

## Issues

1. Whether Diamedix, as patent owner that retained substantial rights under the license, had a direct, legally protectable interest warranting intervention as of right under Rule 24(a)(2) in Abbott’s infringement suit.
2. Whether Abbott’s license conveyed “all substantial rights” such that Abbott could litigate alone without the patent owner’s participation.
3. Whether Abbott adequately represented Diamedix’s interests for Rule 24(a)(2) purposes.

## Decision

- The Federal Circuit reversed the order denying intervention and remanded for further proceedings with Diamedix permitted to participate as a party-plaintiff.
- The court held Abbott did not receive “all substantial rights” in the patents because Diamedix retained significant incidents of ownership.
- The court concluded Diamedix’s interests could be practically impaired by the infringement litigation’s outcome and were not adequately represented by Abbott alone.

## Legal Principles

- Intervention as of right under Rule 24(a)(2) requires: (1) a timely motion, (2) an interest relating to the action’s subject, (3) potential impairment of that interest from disposition, and (4) inadequate representation by existing parties.
- In patent cases, an exclusive licensee may sue in its own name only if it holds “all substantial rights” in the patent; otherwise, the patent owner generally must be joined to protect ownership interests and avoid inconsistent adjudications.
- A license that reserves to the patentee meaningful rights to practice the invention, preserve prior licenses, control transfers/assignments, or protect against settlements that harm patent rights is strong evidence the licensee lacks “all substantial rights.”
- Adequate representation is not established merely because a licensee has an economic incentive to enforce; potential divergence in objectives (including settlement and long-term patent exploitation) may show inadequate representation.

## Conclusion

Because Diamedix retained substantial rights and remained the legal patent owner, it had a protectable interest that could be impaired by the infringement action, and Abbott’s interests were not sufficiently identical to ensure adequate representation; Diamedix was therefore entitled to intervene as of right.


Abbott Labs. v. Diamedix Corp., 47 F.3d 1128 (Fed. Cir. 1995)