Editing Reduction to practice (section)

In [[United States patent law]], the '''reduction to practice''' is the step in the formation of an [[invention]] beyond the conception thereof. Reduction to practice may be either actual (the invention is actually carried out and is found to work for its intended purpose) or constructive (a [[patent application]] having a [[sufficiency of disclosure|sufficient disclosure]] is filed). The date of reduction to practice was critical to the determination of priority between [[inventor]]s in an [[interference proceeding]] under the discontinued [[first-to-invent]] system as well as for [[swear back of a reference|swearing behind a reference]] under that system.<ref>[https://www.uspto.gov/web/offices/pac/mpep/s715.html MPEP § 715]</ref><ref>[https://www.uspto.gov/web/offices/pac/mpep/s2138.html#d0e207753 MPEP § 2138.05]</ref>

Conception is the "formation in the mind of the inventor, of a definite and permanent idea of the complete and operative invention, as it is hereafter to be applied in practice." ''Hybritech Inc. v. Monoclonal Antibodies, Inc.'', [[Case citation|802 F.2d 1367, 1376]] ([[United States Court of Appeals for the Federal Circuit|Fed. Cir.]] 1986) (quoting 1 Robinson ''On Patents'' 532 (1890).

The reduction to practice of an invention can either be:

* Actual reduction to practice: "[R]equires that the claimed invention work[s] for its intended purpose." ''Brunswick Corp. v. U.S.'', [[Case citation|34 Fed. Cl. 532, 584]] (1995).
* Constructive reduction to practice: "[O]ccurs upon the filing of a patent application on the claimed invention." ''Brunswick Corp. v. U.S.'', [[Case citation|34 Fed. Cl. 532, 584]] (1995).
* "Simultaneous conception and reduction to practice": "On rare occasions conception and reduction to practice occur simultaneously in unpredictable technologies." (citing [[Manual of Patent Examining Procedure|MPEP]] §2138.04 "Conception" [R-10.2019]<ref>[https://www.uspto.gov/web/offices/pac/mpep/s2138.html#d0e207607 MPEP § 2138.04]</ref>). "In some instances, such as the discovery of genes or chemicals, an inventor is unable to establish a conception until he has reduced the invention to practice through a successful experiment." ''The Regents of the University of California v. Synbiotics Co.'', [[Case citation|849 F.Supp. 740, 742]] (S.D.Cal., 1994) (citing ''Amgen, Inc. v. Chugai Pharmaceutical Co., Ltd.'', [[Case citation|927 F.2d 1200, 1206]] (Fed. Cir. 1991)). The court will apply this doctrine in so-called "unpredictable arts" such as [[biology]] and [[chemistry]] where the invention is a "biologically active composition of matter," also called a "[[biochemical|bio-chemical]] substance."