Daniel G. Mackrides

I'll research this attorney before drafting.

Let me verify the tracked cases and check for PTAB and other litigation activity.

Let me check the Merus v. Xencor outcome and other matters.

Daniel G. Mackrides — Patent Litigation Practice Summary

Focus areas. Mackrides practices intellectual property litigation in the U.S. District Court for the District of Delaware at Young Conaway Stargatt & Taylor LLP, with a practice the firm describes as spanning patent and trademark infringement, trade secret disputes, derivative suits, and contract disputes. His tracked patent matters are life-sciences cases involving antibody engineering — the Merus litigation concerns bispecific/multispecific antibody platforms (common light-chain transgenic mice and CH3-domain heterodimerization). He holds a B.E. in electrical engineering from the University of Delaware and worked as an engineer for roughly a decade before law school, a background relevant to technically complex disputes. Public dockets also list his name in additional Delaware patent matters across pharma/Hatch-Waxman and technology sectors, though those appearances are outside the two tracked cases and his role in them appears to be Delaware local counsel rather than merits lead.

Side preference and role. The tracked data show two appearances, both on the defendant side (0 plaintiff / 2 defendant), both as local counsel. This is a defense-side, Delaware-local-counsel profile: his name typically appears alongside out-of-state lead firms — Sterne Kessler in the Pfizer/Dexcel matter and Paul Hastings in Merus v. Xencor — filing appearances, stipulations, and case-management papers rather than arguing the substantive merits.

Firm context. Both tracked appearances are at Young Conaway Stargatt & Taylor, where his practice is based. Chambers USA (2025) ranks the firm's Delaware IP practice at Band 2 and notes its dual role as lead counsel and as local counsel to national firms — the latter being the posture in which Mackrides appears. No prior firm history surfaced in the available sources.

Notable matters and outcomes. Merus N.V. v. Xencor, Inc., C.A. No. 24-913-JCB (D. Del.) is the more substantive tracked case: acting for defendant Xencor, the Young Conaway team secured a September 30, 2025 opinion and order from Judge John Campbell Barker granting Xencor's Rule 12(b)(6) motion and dismissing Merus's infringement claims on the ground that the accused antibody-development activity fell within the 35 U.S.C. § 271(e)(1) safe harbor; the court granted leave to amend. Xencor also filed two IPR petitions against the asserted patents in February 2025, but counsel of record on those PTAB filings was Paul Hastings, so no personal PTAB appearance for Mackrides is confirmed. The second tracked matter, Merus BV v. Unknown Defendant, appears to be a placeholder/unknown-defendant filing rather than a contested case. No verdicts, Federal Circuit appeals, or settlements attributable to him individually were identified.

Bar and education. Admitted in Delaware (Bar No. 7230) and Pennsylvania; J.D., summa cum laude, Widener University Delaware Law School, where he was Editor-in-Chief of the Delaware Journal of Corporate Law and published a comment on trade secret law under the Defend Trade Secrets Act, 47 Del. J. Corp. L. 65 (2022); judicial extern for the Hon. Kent A. Jordan, U.S. Court of Appeals for the Third Circuit.