On June 26, 1797, U.S. Patent X177 on a plough, issued to Charles Newbold.
This was the first U.S. patent on a plough, and was followed a steady stream of improvements in agricultural technology. One of the more peculiar of which was the combination plow and cannon, patented by French & Fancher in 1862 (U.S. Patent No. 36600), which must have made the plow-horse very nervous.
In Enanta Pharmaceuticals, Inc. v. Pfizer, Inc., [2025-1427] (June 23, 2026), the Federal Circuit affirmed that all claims of Enanta’s U.S. Patent No. 11,358,953 were invalid as anticipated.
The ‘953 patent claimed priority to a prior provisional patent application that disclosed NHC(O)-C2-C12-alkyl while the ‘953 patent claimed NHC(O)-C1-C12-alkyl. Enanta conteded that it discovered the typographical error in July 9, and filed the application for the ‘953 patent on July 19. The problem was that on April 6 Pfizer made a public disclosure of NHC(O)-C1-alkyl.
The Federal Circuit characterized the issue as “whether ‘2’ provides adequate written description support for ‘1’.” The Federal Circuit said that this was not a case of the correction of an obvious error, noting that the change from C2 to C1 had not been showed here to be a correction of an obvious error, and that the correction was certainly subject to reasonable debate.
The Federal Circuit concluded that the ‘048 provisional does not convey to a skilled artisan that the inventors possessed the NHC(O)-C1-alkyl at the time of filing of the provisional application. The Court observed that “C2 is simply different from C1.” The entitlement to a filing date extends only to that which is disclosed. The Federal Circuit found no genuine issue of material fact, and affirmed summary judgment in favor of Pfizer.
In Ironburg Inventions Ltd. v. Valve Corporation, [2024-2088] (Fed. Cir. 2026), the Federal Circuit reversed and remanded the district court’s grant of partial summary judgment in favor of the patent owner on the issue of IPR estoppel, finding that estoppel did not apply because it was not shown that a reasonably diligent search could have been expected to discover the references at issue.
Valve challenged Ironburg’s patent in a first IPR, and again in a second IPR. After the Final Written decision in the first IPR, IPR Ironburg successfully asserted estoppel under 35 USC 315(e)(1), the Board finding that a skilled searcher conducting a reasonably diligent search could have been expected to discover the reference on which the second IPR was based. A third party also filed an IPR against Ironburg’s patent, and Valve tried to amend its invalidity contentions in Ironburg’s infringement suit against it. Ironburg moved for estoppel under 35 USC 315(e)(1), arguing that Valve should be estopped form asserting the grounds raised by the third-party IPR. The District Court found that because the third party found the prior art, a skilled searcher could reasonably be expected to find the same prior art.
In a first appeal, the Federal Circuit held that the district erred in placing the burden on Valve to show that Valve reasonably could not have raised the third-party ground during the first IPR, when the burden was on Ironburg to show that estoppel applied to Valve. The Federal Circuit further held that Ironburg failed to meet its burden by merely relying on the fact that the third party found the prior art, without any evidence about the third party’s diligence in finding the prior art. On remand, the district court again found Valve was estopped as to the prior art in the Valve’ second IPR and as to the prior art from the third party IPR.
Ironburg relied on searches by a private search company to show that the grounds in the prior IPRs would have been discoverable to a skilled searcher exercising reasonable diligence, and the district court determine that the prior art was reasonably discoverable. In the present appeal, Valve argued: (1) that its pre-petition search evidence does not demonstrate that references were discoverable under a proper articulation of the skilled searcher standard, and (2) that Ironburg’s evidence from third-party searchers was irrelevant to the skilled searcher inquiry.
Regarding the skilled searcher inquiry, the Federal Circuit said the statutory language requires a focus on what reasonably, rather than possibly, could have been raised prior to the filing of a relevant IPR petition. The Federal Circuit said when evidence is introduced that sheds light on what a skilled searcher may have discovered only after the time of the relevant IPR petition, such evidence is likely irrelevant to the skilled searcher inquiry.
The Federal Circuit identified two open questions regarding the skilled searcher inquiry: First, whether the skilled searcher inquiry poses a question of law, reviewable de novo, or a question of fact, reviewable for clear error. Second what “discovery” within the skilled searcher inquiry entails. However the Federal Circuit neatly ducked both questions, finding that the reference was unfindable under any conception of what the skilled searcher.
The Federal Circuit said that a reference was not discoverable merely because it is located in classifications that a searcher would believe to be relevant – at least where an unreviewably large number of references are returned by a skilled searcher’s diligent search. This was in line with preponderant evidence of record in this case, which indicated that keyword searches or other narrowing techniques would be used after an initial classification search. Because the district court was confronted with thousands of references in the search results yet still found that no narrowing was required for the reference to be deemed discovered, the Federal Court concluded the district court erred, warranting reversal of the finding of estoppel.
The Federal Circuit then addressed whether a search that was not date restricted to exclude references after the filing of the IPR Petition involved hindsight. Because the searching included forward-and-backward searching the failure to exclude subsequent references which could contain backward citations could misrepresent what a reasonable search could find at the time the IPR was filed. The Federal Circuit agreed, finding that the failure to date limit searches employing forward-and-backward searching taints the results of what a skilled searcher at the time of an IPR would discover.
Judge Stark wrote separately to highlight certain aspects, noting:
On June 7, 2005, David P. Coughlin received U.S. Patent No. 6,901,925 on a Fireplace with Waterfall:
While it is not clear whether Mr. Coughlin had any success before his patent expired, the idea of mixing fire and water is a popular one with inventors:
On June 6, 1995, Peter and John Kockelman et al., received U.S. Patent No. 5,421,783 on a Human Slingshot Machine.
While a human slingshot is not for everyone, it is considerably safer than the human cross bow from U.S. Patent No. 562448:
I suppose that that is the march of progress (or perhaps OSHA).
On June 5, 1945, Frank W. Schwinn received U.S. Patent No. D141505 on a Tandem Bicycle:
Frank W. Schwinn was the son of Ignaz Schwinn, who founded the Schwinn bicycle company in 1895, Frank joined the company around 1918, taking over leadership of the company during the Great Depression, and running the company until his death in 1963.
Frank’s design was not the first tandem bicycles — which became popular in the 1880’s, and boomed in the 1890’s after Harry Dacre’s 1892 song “Daisy Bell” (The Bicycle Built for Two song). Nor was Frank’s design the first Schwin tandem bicycle — his father Ignaz had been manufacturing Tandem bicycles since the 1890’s. In fact, Frank’s design may never have been produced. in the 1940’s, Schwinn Tandem’s had a very different chain guard, as shown in this advertisement in the 1948 catalog featuring comedian Bob Hope:
Even if this design was never commercialized, Frank W. Scwhinn made numerous contributions to the design and manufacture of bicycles in a career spanning 5 decades, ending in his death in 1963, when the third generation of Schwinn, Frank V. Schwinn took over the company.
In Hikma Pharmaceuticals USA Inc. v. Amarin Pharma, 608 U.S. ____ (2026), the Supreme Court reversed the Federal Circuit, holding that Amarin failed to state a claim for active inducement of its patents on Vascepa.
The Court began by identifying the three requirements of an inducement claim: (1) direct infringement by a third party; (2) the inducer’s knowledge that the induced acts constitute infringement; and (3) the inducer must take active steps to encourage direct infringement.
Hikma submitted an ANDA to market Vascepa for severe hypertriglyceridemia (the SH indication), and succeeded in invalidating Hikma’s patent on the treatment of severe hypertriglyceridemia. In the meantime, the FDA approved Vascepa for treating hypertriglyceridemia in patients already on statins (the CV indication) and Amarin obtained two new method of use patents for the CV indication. Hikma went forward preparing to mark Vascepa adopting a skinny label only referencing the now-unpatented SH indication, preparing a leaflet that its drug was for “people who have heart (cardiovascular) disease”; and describing its product as “therapeuticallly equivalent to Cascepa, and listing its therapeutic category broadly as “hyperglyceridemia”; and issuing a series of press releases describing its product as “generic Vascepa.”
The Supreme Court said that inducement must involve the taking of affirmative, as opposed to passive, steps to bring about the desired result of patent infringement. To avoid interfering with “regular commerce” ordinary acts incident to product distribution are insufficient to support liability. The Supreme Court found that Hikma’s statements came up short.
Of all of Hikma’s statements, the press releases calling their product generic Vascepa see the most culpable, since the product was not a replacement for all indications., However the Supreme Court dismissed this, explaining that it was to truthfully describe a generic drug as an “equivalent” to the brand-name comparator. The court declined to “put generic manufacturers between a rock and a hard place by turning adherence to the law and industry standards into building blocks for illegal conduct.”
The Supreme Court explained the law requires active not passive inducement, so the question is not merely whether the statement could be plausibly understood to induce infringement, but whether they plausibly understood to induce infringement. Viewed in that light, the Supreme Court found Hikma’s statements to be implausibly roundabout ways to induce medical providers to infringe.
It would seem that if Amarin gave different names to the formulation for different indications — even something as simple as Vascepa-SH and Vascepa-CV would have prevented Hikma from referring to its product as generic Vascepa, instead having to use “generic Vascepa-SH” more clearly indicated that it is not approved for the Vascepa-CV indication.
On April 22, 1924, U.S. Patent No. 1,490,987 issued to Harry E. Soref on a lock casing:
Soref’s innovation was making the lock body from a plurality of steel laminations secured together with rivets — a construction still widely used 102 years later.
Soref was born in 1887 Bilozirka, Ukraine, and emigrated to the U.S. where he worked as a lock smith. When he was unable to find a taker for his lock design, he co-founded the Master Lock company with two friends — Samuel Stahl and Phillip E. Yolles, in Milwaukee, Wisconsin, to build his locks. Mr. Soref held more than eighty patents for locks and lock-making machinery.
He died in 1957 in Phoenix, Arizona, aged 70.
On April 21, 1857, U.S. Patent No. 17082 issued to Alexander Douglas on a Bustle:
While necessity may be the mother of invention, the ‘082 patent is proof that necessity is not always, the mother of invention.
The earliest U.S. patent reference to a bustle was U.S. Patent No. 4897, issued December 17, 1846, predating Douglas’ invention by nearly 11 years. Douglas’ patent was the start of a frenzy as inventors hustled to the Patent Office invention with their bustles, and 15 more bustle patents issued in the next two years: U.S. Patent Nos. 17,602, 20,263, 20,681, 20,801, 20,865, 21479, 21,806, 22,124, 22,133, 22,197, 22,242, 22,426, 22,532, 22,875 and 23,681. While inventors’ interest in bustles died down before the end of the 19th century, it has never completely gone away, with U.S. Patent No. 12582183 issuing on March 24, 2026, on a Bustle Device to Be Received Under Garments.
On March 14, 1899, U.S. Patent No. 621195 issued to Ferdinand Graf Zeppelin on a navigable balloon:
Ferdinand Graf Zeppeli was born July 8, 1838, he was a Count and general. He served as an official observer with the Union Army during the U.S Civil War, visiting the balloon camp of Thaddeus Lowe, and then made his first ascent in a balloon in St. Paul with former Army balloonist John Steiner, which was the inspiration of his later interest in aeronautics. Zeppelin’s ideas for large airships were first recorded in a March 25, 1874, diary entry.
After resigning from the Army in 1891, at the age of 52, Zeppelin devoted himself to designing an air ship. He patented the design in Germany in 1895 and in the United States in 1899. After initial succes, the name Zeppelin came to be commonly used to refer to all forms of rigid airships. Zeppelin also created the world’s first commercial airline, using his air ships.