BOARD OF REGENTS OF THE UNIVERSITY OF TEXAS v. BOSTON SCIENTIFIC CORP.

Authored by: Jeremy Gustrowsky

The Federal Circuit has reversed a Delaware jury verdict that found Boston Scientific liable for infringing a University of Texas patent covering drug-releasing biodegradable polymer fibers, holding that Boston Scientific was entitled to judgment as a matter of law on both invalidity and noninfringement grounds. 

The case centered on U.S. Patent No. 6,596,296, owned by the Board of Regents of the University of Texas, which claims compositions containing biodegradable polymer fibers with dispersed therapeutic agents for use in implants. UT and TissueGen accused Boston Scientific’s drug-eluting coronary stent systems of infringing claims 1, 11, 17, and 26. A jury sided with UT, finding willful infringement and rejecting Boston Scientific’s anticipation defense, though the district court later set aside the willfulness finding. 

On the invalidity question, the court found that U.S. Patent No. 5,364,627 (Song), a prior-art reference disclosing gradual release of active agents (including drugs) from fibers, anticipated all four asserted claims. The court rejected UT’s attempt to characterize Song as merely a “chewing gum patent,” noting that Song expressly discloses biodegradable polymers, drugs as active agents, and release through solvent exposure. Song’s teaching that the active agent “does not necessarily have to be in a contiguous phase” directly satisfied the claim requirement for “discrete drug-containing regions,” since non-contiguous regions are by definition discrete. 

For dependent claim 26, which requires release “at varying rates over time,” the court relied on unrebutted expert testimony that all drug delivery systems inherently have varying release rates, along with Song’s figures showing pockets and openings of varying sizes. The court dismissed UT’s argument that Song’s language about “limiting” dissolution rates implied a fixed rate, explaining that a cap on release does not suggest uniform release below that cap. 

Although the anticipation holding was sufficient to resolve the case, the court also addressed noninfringement. The district court had construed “fiber” as “a thread-like structure of any length or shape,” and UT’s infringement theory relied on characterizing a zigzag-shaped section of coating (theoretically cut away from the stent’s metal frame) as the claimed fiber. The Federal Circuit found this untenable, noting the coating “needs a substrate” to exist, was tubular with zigzagging walls matching the metal frame, and was more ribbon-like than thread-like. The court analogized: one cannot reasonably say that a uniform sheet of paper contains a narrow strip simply because one can cut such a strip from it. 

The court reversed the judgment for UT entirely, awarded costs to Boston Scientific, and declined to reach UT’s cross-appeal on willfulness or Boston Scientific’s other challenges to trial conduct. The decision serves as a reminder that expert testimony distinguishing a prior-art reference must actually address the claim limitations at issue, not unclaimed features like release mechanism direction.