Why a Practitioner Must Always Proofread Claims Before Filing Suit

The CAFC recently held that even though a patentee corrected an unintentional typo just after filing suit, the suit was limited to the uncorrected claim. The uncorrected claim was later found to be obvious because it was missing a limitation (the typo). The suit, H-W Technology, L.C. v. Overstock.com, Inc., issued July 11, 2014, should forewarn practitioners that even obvious clerical errors in patent claims can spell trouble for lawsuits if not corrected.

In this case, even though Overstock acquired a certificate of correction several months before realizing the error, it did not move to amend its complaint to reflect the correction. The Federal Circuit held that the District Court had no power to amend the mistake and, therefore, the claim was asserted and unenforceable.