Once an invention is actually reduced to practice an inventor need not rush to file a patent application. Shindelar v. Holdeman, 628 F.2d 1337, 1341, 207 USPQ 112, 116 (CCPA 1980). The length of time taken to file a patent application after an actual reduction to practice is generally of no consequence except in an interference proceeding. Paulik v. Rizkalla, 760 F.2d 1270, 1271, 226 USPQ 225, 226 (Fed. Cir. 1985) (suppression or concealment may be deliberate or may arise due to an inference from a “too long” delay in filing a patent application). Peeler v. Miller, 535 F.2d 647, 656, 190 USPQ 117,124 (CCPA 1976) (“mere delay, without more, is not sufficient to establish suppression or concealment.” “What we are deciding here is that Monsanto’s delay is not ‘merely delay’ and that Monsanto's justification for the delay is inadequate to overcome the inference of suppression created by the excessive delay.” The word “mere” does not imply a total absence of a limit on the duration of delay. Whether any delay is “mere” is decided only on a case-by-case basis.).

Once an invention is actually reduced to practice an inventor need not rush to file a patent application. Shindelar v. Holdeman, 628 F.2d 1337, 1341, 207 USPQ 112, 116 (CCPA 1980). The length of time taken to file a patent application after an actual reduction to practice is generally of no consequence except in an interference proceeding. Paulik v. Rizkalla, 760 F.2d 1270, 1271, 226 USPQ 225, 226 (Fed. Cir. 1985) (suppression or concealment may be deliberate or may arise due to an inference from a “too long” delay in filing a patent application). Peeler v. Miller, 535 F.2d 647, 656, 190 USPQ 117,124 (CCPA 1976) (“mere delay, without more, is not sufficient to establish suppression or concealment.” “What we are deciding here is that Monsanto’s delay is not ‘merely delay’ and that Monsanto's justification for the delay is inadequate to overcome the inference of suppression created by the excessive delay.” The word “mere” does not imply a total absence of a limit on the duration of delay. Whether any delay is “mere” is decided only on a case-by-case basis.).

Once an invention is actually reduced to practice an inventor need not rush to file a patent application. Shindelar v. Holdeman, 628 F.2d 1337, 1341, 207 USPQ 112, 116 (CCPA 1980). The length of time taken to file a patent application after an actual reduction to practice is generally of no consequence except in an interference proceeding. Paulik v. Rizkalla, 760 F.2d 1270, 1271, 226 USPQ 225, 226 (Fed. Cir. 1985) (suppression or concealment may be deliberate or may arise due to an inference from a “too long” delay in filing a patent application). Peeler v. Miller, 535 F.2d 647, 656, 190 USPQ 117,124 (CCPA 1976) (“mere delay, without more, is not sufficient to establish suppression or concealment.” “What we are deciding here is that Monsanto’s delay is not ‘merely delay’ and that Monsanto's justification for the delay is inadequate to overcome the inference of suppression created by the excessive delay.” The word “mere” does not imply a total absence of a limit on the duration of delay. Whether any delay is “mere” is decided only on a case-by-case basis.).

Once an invention is actually reduced to practice an inventor need not rush to file a patent application. Shindelar v. Holdeman, 628 F.2d 1337, 1341, 207 USPQ 112, 116 (CCPA 1980). The length of time taken to file a patent application after an actual reduction to practice is generally of no consequence except in an interference proceeding. Paulik v. Rizkalla, 760 F.2d 1270, 1271, 226 USPQ 225, 226 (Fed. Cir. 1985) (suppression or concealment may be deliberate or may arise due to an inference from a “too long” delay in filing a patent application). Peeler v. Miller, 535 F.2d 647, 656, 190 USPQ 117,124 (CCPA 1976) (“mere delay, without more, is not sufficient to establish suppression or concealment.” “What we are deciding here is that Monsanto’s delay is not ‘merely delay’ and that Monsanto's justification for the delay is inadequate to overcome the inference of suppression created by the excessive delay.” The word “mere” does not imply a total absence of a limit on the duration of delay. Whether any delay is “mere” is decided only on a case-by-case basis.).

Once an invention is actually reduced to practice an inventor need not rush to file a patent application. Shindelar v. Holdeman, 628 F.2d 1337, 1341, 207 USPQ 112, 116 (CCPA 1980). The length of time taken to file a patent application after an actual reduction to practice is generally of no consequence except in an interference proceeding. Paulik v. Rizkalla, 760 F.2d 1270, 1271, 226 USPQ 225, 226 (Fed. Cir. 1985) (suppression or concealment may be deliberate or may arise due to an inference from a “too long” delay in filing a patent application). Peeler v. Miller, 535 F.2d 647, 656, 190 USPQ 117,124 (CCPA 1976) (“mere delay, without more, is not sufficient to establish suppression or concealment.” “What we are deciding here is that Monsanto’s delay is not ‘merely delay’ and that Monsanto's justification for the delay is inadequate to overcome the inference of suppression created by the excessive delay.” The word “mere” does not imply a total absence of a limit on the duration of delay. Whether any delay is “mere” is decided only on a case-by-case basis.).

Pre-AIA 35 U.S.C. 102(g) generally makes available as prior art within the meaning of 35 U.S.C. 103, the prior invention of another who has not abandoned, suppressed or concealed it. In re Bass, 474 F.2d 1276, 177 USPQ 178 (CCPA 1973); In re Suska, 589 F.2d 527, 200 USPQ 497 (CCPA 1979) (The result of applying the suppression and concealment doctrine is that the inventor who did not conceal (but was the de facto last inventor) is treated legally as the first to invent, while the de facto first inventor who suppressed or concealed is treated as a later inventor. The de facto first inventor, by suppression and concealment, lost the right to rely on the actual date of invention not only for priority purposes, but also for purposes of avoiding the invention of the counts as prior art.).

Pre-AIA 35 U.S.C. 102(g) generally makes available as prior art within the meaning of 35 U.S.C. 103, the prior invention of another who has not abandoned, suppressed or concealed it. In re Bass, 474 F.2d 1276, 177 USPQ 178 (CCPA 1973); In re Suska, 589 F.2d 527, 200 USPQ 497 (CCPA 1979) (The result of applying the suppression and concealment doctrine is that the inventor who did not conceal (but was the de facto last inventor) is treated legally as the first to invent, while the de facto first inventor who suppressed or concealed is treated as a later inventor. The de facto first inventor, by suppression and concealment, lost the right to rely on the actual date of invention not only for priority purposes, but also for purposes of avoiding the invention of the counts as prior art.).

[Editor Note: This MPEP section has limited applicability to applications subject to examination under the first inventor to file (FITF) provisions of the AIA as set forth in 35 U.S.C. 100 (note). Patents and applications that contain (or contained at any time) at least one claim with a pre-AIA effective filing date (before March 16, 2013) and at least one claim with a post-AIA effective filing date (on or after March 16, 2013) are subject to the patentability requirements in AIA 35 U.S.C. 102 – 103 and subject to pre-AIA 35 U.S.C. 102(g).See MPEP § 2159 et seq.]

[Editor Note: This MPEP section has limited applicability to applications subject to examination under the first inventor to file (FITF) provisions of the AIA as set forth in 35 U.S.C. 100 (note). Patents and applications that contain (or contained at any time) at least one claim with a pre-AIA effective filing date (before March 16, 2013) and at least one claim with a post-AIA effective filing date (on or after March 16, 2013) are subject to the patentability requirements in AIA 35 U.S.C. 102 – 103 and subject to pre-AIA 35 U.S.C. 102(g).See MPEP § 2159 et seq.]

Where a junior party in an interference relies upon an actual reduction to practice to demonstrate first inventorship, and where the hiatus in time between the date for the junior party's asserted reduction to practice and the filing of its application is unreasonably long, the hiatus may give rise to an inference that the junior party in fact suppressed or concealed the invention and the junior party will not be allowed to rely upon the earlier actual reduction to practice. Young v. Dworkin, 489 F.2d 1277, 1280 n.3, 180 USPQ 388, 391 n.3 (CCPA 1974) (suppression and concealment issues are to be addressed on a case-by-case basis).

Notwithstanding an inference of suppression or concealment due to time(s) of inactivity after reduction to practice, the senior party may still prevail if the senior party shows renewed activity on the invention that is just prior to the junior party’s entry into field coupled with the diligent filing of an application. Lutzker v. Plet, 843 F.2d 1364, 1367-69, 6 USPQ2d 1370, 1371-72 (Fed. Cir. 1988) (activities directed towards commercialization not sufficient to rebut inference); Holmwood v. Cherpeck, 2 USPQ2d 1942, 1945 (Bd. Pat. App. & Inter. 1986) (the inference of suppression or concealment may be rebutted by showing activity directed to perfecting the invention, preparing the application, or preparing other compounds within the scope of the generic invention); Engelhardt v. Judd, 369 F.2d 408, 411, 151 USPQ 732, 735 (CCPA 1966) (“We recognize that an inventor of a new series of compounds should not be forced to file applications piecemeal on each new member as it is synthesized, identified and tested for utility. A reasonable amount of time should be allowed for completion of the research project on the whole series of new compounds, and a further reasonable time period should then be allowed for drafting and filing the patent application(s) thereon.”); Bogoslowsky v. Huse, 142 F.2d 75, 77, 61 USPQ 349, 351 (CCPA 1944) (The doctrine of suppression and concealment is not applicable to conception without an actual reduction to practice.).

Notwithstanding an inference of suppression or concealment due to time(s) of inactivity after reduction to practice, the senior party may still prevail if the senior party shows renewed activity on the invention that is just prior to the junior party’s entry into field coupled with the diligent filing of an application. Lutzker v. Plet, 843 F.2d 1364, 1367-69, 6 USPQ2d 1370, 1371-72 (Fed. Cir. 1988) (activities directed towards commercialization not sufficient to rebut inference); Holmwood v. Cherpeck, 2 USPQ2d 1942, 1945 (Bd. Pat. App. & Inter. 1986) (the inference of suppression or concealment may be rebutted by showing activity directed to perfecting the invention, preparing the application, or preparing other compounds within the scope of the generic invention); Engelhardt v. Judd, 369 F.2d 408, 411, 151 USPQ 732, 735 (CCPA 1966) (“We recognize that an inventor of a new series of compounds should not be forced to file applications piecemeal on each new member as it is synthesized, identified and tested for utility. A reasonable amount of time should be allowed for completion of the research project on the whole series of new compounds, and a further reasonable time period should then be allowed for drafting and filing the patent application(s) thereon.”); Bogoslowsky v. Huse, 142 F.2d 75, 77, 61 USPQ 349, 351 (CCPA 1944) (The doctrine of suppression and concealment is not applicable to conception without an actual reduction to practice.).