1. Cases Involving Claims of Infringement or Invalidity
(Including Hatch-Waxman Cases)
U.S. District Court of Maryland Local Rules (December 1, 2025)
to narrow the issues in dispute and exchange revised lists of
terms/constructions.
c) Claim Construction Briefing
i. Not later than thirty-five (35) days from the exchange of the
“Preliminary Claim Construction and Extrinsic Evidence,” each party
shall serve and file an opening brief and any evidence supporting its
claim construction. If any party opposing patent infringement
contends that any claim terms are indefinite, that party shall raise the
issue in its opening claim construction brief. Any expert declaration in
support of a party’s position must be submitted with its opening brief.
All asserted patents shall be attached as exhibits to the opening claim
construction brief in searchable PDF form.
ii. Not later than twenty-eight (28) days from the deadline for filing the
opening brief, each party shall serve and file a responsive brief and
supporting evidence. If any party opposing patent infringement
contended that a claim term is indefinite in its opening brief, each party
asserting patent infringement shall respond to the indefiniteness issue
in its responsive brief. Any expert declaration responding to a party’s
position set forth in its opening brief must be submitted with its
responsive brief.
iii. Not later than fourteen (14) days from the deadline for filing the
responsive brief, each party shall serve and file any reply brief and any
evidence directly rebutting the supporting evidence contained in an
opposing party’s response. No expert declarations may be submitted
with a reply brief without leave of court, and for good cause.
iv. If a party offers the testimony of a witness to support its claim
construction, it must make the witness available for deposition (if the
witness is under the control of the party) concerning the proposed
testimony. Any party may utilize a rebuttal expert in response to a
brief where expert testimony is relied on by the other party. If a
witness is deposed based on a declaration submitted in the responsive
brief, the parties’ deadline for the filing of the reply brief shall be
extended by seven (7) calendar days.
