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In Sun Pharmaceutical Industries, Ltd. v. Eli Lilly & Co., 611 F.3d 1381 (Fed. Cir. 2010), the Federal Circuit affirmed summary judgment invalidating claims 2, 6, and 7 of U.S. Patent No. 5,464,826 covering methods of treating cancer with gemcitabine (Gemzar) for obviousness-type double patenting over Lilly's earlier U.S. Patent No. 4,808,614. Circuit Judge Sharon Prost held that under the Schneller and Geneva doctrine, where an issued patent claims a chemical compound and its specification explicitly discloses an anticancer utility, an innovator cannot subsequently obtain a separate patent claiming that exact disclosed utility to prolong its commercial exclusivity. The court rejected Lilly's contention that double patenting is strictly restricted to claim-to-claim comparisons, establishing that disclosed utilities in the specification demonstrate whether subsequent method claims are patentably distinct. This decisive ruling stripped Lilly of an anticipated 2.5-year exclusivity extension, unlocking generic gemcitabine competition across oncology markets upon compound patent expiration in May 2010.

In a landmark Hatch-Waxman battle against a vast consortium of generic challengers led by Accord Healthcare, Aurobindo Pharma, and Sun Pharma, the Federal Circuit upheld the validity of U.S. Patent No. RE38,551 covering lacosamide (Vimpat). The appellate court held that prior art Compound 3l was not a viable lead compound under 35 U.S.C. 103 due to disclosed central nervous system toxicity, and rejected the argument that isolating the active (R)-enantiomer was obvious without prior appreciation of stereoselective sodium channel slow inactivation.

In Altana Pharma AG v. Teva Pharmaceuticals USA, Inc., 566 F.3d 999 (Fed. Cir. 2009), the Federal Circuit affirmed the denial of a preliminary injunction, holding that generic challengers Teva and Sun Pharma raised a substantial question of patent invalidity under 35 U.S.C. 103 against U.S. Patent No. 4,758,579 covering Protonix (pantoprazole sodium). Circuit Judge Arthur J. Gajarsa held that prior art Compound 12 from Altana's earlier '518 patent was a natural lead compound because published preclinical data proved it possessed superior gastric acid inhibitory potency and lower acute toxicity than omeprazole. The court rejected Altana's attempt to disqualify Compound 12 using undisclosed, internal thyroid toxicity data, ruling that secret testing cannot defeat prior art teachings available to skilled artisans. Furthermore, modifying the 3-position of the pyridine ring from a methyl to a methoxy group was supported by established structure-activity relationships governing pyridine nitrogen pKa and acid stability, demonstrating that close structural analogs with predictable electronic effects face intense obviousness vulnerability.

The Federal Circuit affirms the preliminary injunction against South Korean biosimilar manufacturer Samsung Bioepis, enforcing Regeneron's patent rights for the FDA-approved drug EYLEA.

In The Procter & Gamble Company v. Teva Pharmaceuticals USA, Inc., the Federal Circuit delivered a cornerstone ruling clarifying chemical obviousness post-KSR. Rejecting Teva's attempt to invalidate the patent on Actonel (risedronate) as an obvious positional isomer of 2-pyr EHDP, the court held that structural similarity alone cannot establish obviousness without proving that a skilled artisan would have selected the prior art molecule as a lead compound. Because the prior art compound produced severe bone mineralization defects and had a narrow therapeutic margin, its toxic profile taught away from lead selection, while risedronate's 1,000-fold expansion in therapeutic index constituted an unexpected difference in kind.

In Pfizer Inc. v. Ranbaxy Laboratories Ltd., 457 F.3d 1284 (Fed. Cir. 2006), the Federal Circuit reversed a district court validity ruling, holding that Claim 6 of U.S. Patent No. 5,273,995 covering the hemicalcium salt of atorvastatin was invalid under 35 U.S.C. 112, paragraph 4. Because parent Claim 2 was strictly limited to the free carboxylic acid form and excluded salts, a dependent claim purporting to claim a salt form was contradictory and impermissibly exceeded its parent scope, establishing that courts cannot rewrite flawed dependent claims to salvage secondary pharmaceutical patents.

The Federal Circuit affirms the district court's decision that Novartis's patent lacked an adequate written description, impacting the scope of patent protection for pharmaceutical compositions.

When AstraZeneca attempted to patent a streamlined manufacturing process for Prilosec (omeprazole) where an intermediate separating subcoat formed in situ between the alkaline core and the acidic enteric coating, generic challengers including Cheminor Drugs (Dr. Reddy's) and Andrx proved that an earlier published Korean patent inevitably produced that identical subcoat. The Federal Circuit affirmed that inherent anticipation does not require prior recognition or appreciation: following an old chemical recipe inherently produces all of its natural consequences, and an innovator cannot recapture a known process from the public domain simply by discovering and naming the underlying reaction.

In Aventis Pharma Deutschland GmbH v. Lupin, Ltd., 499 F.3d 1293 (Fed. Cir. 2007), the U.S. Court of Appeals for the Federal Circuit reversed a district court validity judgment, holding that patent claims to the isolated 5(S) stereoisomer of ramipril (Altace) were invalid as obvious over prior art disclosing stereoisomer mixtures, establishing that isolating an active isomer using routine chromatography when structure-activity relationships point to its potency is prima facie obvious.

In Schering Corp. v. Geneva Pharmaceuticals, Inc., 339 F.3d 1373 (Fed. Cir. 2003), the U.S. Court of Appeals for the Federal Circuit affirmed that a prior art patent teaching the administration of loratadine (Claritin) inherently anticipated subsequent claims to its active metabolite, desloratadine (DCL), establishing that discovering an unrecognized in vivo chemical byproduct does not warrant a new compound monopoly.

When generic challenger Mylan attempted to invalidate Ortho-McNeil's core composition patent on topiramate (Topamax, U.S. Patent No. 4,513,006), it argued under KSR that synthesizing a sulfamate-substituted fructose derivative was an obvious-to-try combination of known intermediates. The Federal Circuit affirmed that post-KSR obviousness requires a finite number of identified, predictable solutions. Because topiramate arose from an unpredicted reaction detour during research directed at an entirely unrelated disease target (diabetes), serendipitous chemical intermediate synthesis and unexpected anticonvulsant efficacy completely defeated obviousness.

The Federal Circuit reversed a district court's judgment, upholding Teva Pharmaceuticals' headache patents against Lilly's claims of invalidity, emphasizing the importance of detailed patent claims in the pharma industry.

When generic challengers attempted to invalidate AstraZeneca and Shionogi's blockbuster statin Crestor (rosuvastatin calcium, U.S. Patent No. RE37,314), they argued that substituting a polar methanesulfonamide group onto a prior art Sandoz pyrimidine core was an obvious, routine optimization. The Federal Circuit affirmed that the prior art's rigid structure-activity dogma demanding lipophilic substituents at the heterocyclic core actively taught away from polar sulfonyl modifications, affirming the validity of the foundational small-molecule patent.

When AstraZeneca drafted its foundational esomeprazole patents, the independent claims broadly claimed an alkaline salt. But the specification explicitly described the invention by singling out six specific cations: sodium, potassium, lithium, magnesium, calcium, and ammonium. In AstraZeneca AB v. Hanmi USA, Inc., the Federal Circuit affirmed that this clear specification language disclaimed other counterions, allowing Hanmi to market esomeprazole strontium under section 505(b)(2) without infringing.

When Alphapharm challenged Takeda's patent on the blockbuster diabetes therapy Actos (pioglitazone), it argued the drug was an obvious modification of a prior art thiazolidinedione dubbed "Compound b." To bridge the structural gap, Alphapharm asked the court to perform two simultaneous alterations: "ring walking" a methyl group around a pyridine heterocycle from the 6-position to the 5-position, and homologating that methyl group into an ethyl substituent. The Federal Circuit firmly rejected this hindsight reconstruction, holding that a 34% body weight increase and brown fat proliferation reported for Compound b actively taught away from selecting it as a lead compound, establishing the canonical two-step test for chemical obviousness.

When generic challenger Ivax and Indian API manufacturer Cipla argued that isolating escitalopram from racemic citalopram was obvious under 35 U.S.C. 103, the Federal Circuit held that where a racemate stubbornly resists conventional separation and requires inventing a novel synthetic intermediate route, the isolated enantiomer is patentable.

In Sanofi-Synthelabo v. Apotex, Inc., 550 F.3d 1075 (Fed. Cir. 2008), the Federal Circuit affirmed the validity of claim 1 of U.S. Patent No. 4,847,265 covering clopidogrel bisulfate (Plavix). Although the racemic precursor PCR 4099 was disclosed in prior art, resolving the racemate unexpectedly segregated 100% of the antiplatelet therapeutic efficacy into the dextrorotatory enantiomer while leaving behind fatal convulsant neurotoxicity in the levorotatory isomer. Furthermore, while 20 screened salts yielded unstable, amorphous degrading gums, only the hydrogen sulfate (bisulfate) salt formed a stable, non-hygroscopic crystalline matrix. The court held that unpredictable separation of biological properties and unexpected salt crystallization defeat obviousness under 35 U.S.C. 103.

When generic challenger Matrix Laboratories attacked Daiichi Sankyo's patent on olmesartan medoxomil (Benicar), it argued that swapping a lipophilic group for a hydrophilic tertiary hydroxyalkyl on an imidazole core was obvious over DuPont's prior art. The Federal Circuit affirmed patent validity, holding that established structure-activity relationships taught away from hydrophilic modifications at that position.

When Pfizer discovered that its lead amlodipine maleate salt degraded via Michael addition and stuck to tablet punch faces during manufacturing, it screened 53 pharmaceutically acceptable counter-ions from the literature and patented amlodipine besylate. In Pfizer, Inc. v. Apotex, Inc., 480 F.3d 1348 (Fed. Cir. 2007), the Federal Circuit reversed a district court validity ruling, holding that screening a finite catalog of known anions to solve predictable formulation liabilities is routine verification testing that renders the resulting salt patent obvious under 35 U.S.C. 103.

When Eli Lilly obtained a selection patent for olanzapine, Dr. Reddy's challenged its validity, arguing that Lilly's earlier broad patent application had already disclosed the molecule within a Markush genus covering millions of potential thienobenzodiazepines. The UK Court of Appeal held that an umbrella description of a chemical genus does not constitute an individualized description of every species within it. Because olanzapine exhibited an unexpected technical advantage--avoiding the acute dog liver toxicity of the halogenated prior art lead and the agranulocytosis risk of clozapine--its selection was patentable.

In Otsuka Pharmaceutical Co., Ltd. v. Sandoz, Inc., 678 F.3d 1280 (Fed. Cir. 2012), the U.S. Court of Appeals for the Federal Circuit affirmed that the claims covering aripiprazole (Abilify) were not invalid for obviousness, establishing a bedrock precedent that an inventor's successful path cannot be used retroactively as a blueprint to destroy their patent.

The Federal Circuit affirmed the invalidation of Enanta's COVID-19 antiviral patent because their provisional application recited a C2-C12 alkyl group, explicitly excluding the critical C1 moiety found in Pfizer's Paxlovid (nirmatrelvir). The court ruled that an alleged typographical error cannot retroactively confer possession of an excluded chemical species.

The Federal Circuit affirmed the validity of Exelixis's U.S. Patent No. 11,091,439 covering crystalline cabozantinib (L)-malate. The core holding established that disclosing the chemical name, formula, and crystalline nature of the salt was sufficient to meet the written description requirement for a broad genus claim covering all crystalline forms, even though the specification explicitly described only two polymorphs.

The Federal Circuit affirmed the PTAB's decision that Concert Pharmaceuticals' (now Sun Pharma) deuterated ruxolitinib patent was obvious. The court ruled that leveraging the kinetic isotope effect to improve metabolic stability at known cytochrome P450 oxidation sites is predictable, clearing the path for future development.

In a landmark ruling for pharmaceutical patent portfolios, the Federal Circuit held that a first-filed, first-issued patent benefiting from Patent Term Adjustment (PTA) cannot be invalidated for obviousness-type double patenting (ODP) by its own later-filed, earlier-expiring continuation patents, effectively blocking early generic entry for Viberzi (eluxadoline).

The Delhi High Court's recent semaglutide decision establishes a critical precedent for Section 64 obviousness challenges against genus patents, allowing Dr. Reddy's to manufacture and export the GLP-1 agonist while domestic sales remain restrained.

Pioglitazone (Actos) is a blockbuster thiazolidinedione (TZD) insulin sensitizer. In Takeda v. Alphapharm, the generic challenger argued it was an obvious derivative of a prior art methyl-substituted TZD (Compound b). The Federal Circuit held that the known toxicity of Compound b (weight gain and brown fat) actively taught away from selecting it as a lead compound.

In Eisai Co. v. Dr. Reddy's Laboratories, Ltd., the Federal Circuit affirmed that claim 1 of U.S. Patent No. 5,045,552 covering Aciphex (rabeprazole) was not obvious under 35 U.S.C. 103 over lansoprazole. While lansoprazole and rabeprazole differ only at the 4-position of the pyridine ring (trifluoroethoxy vs methoxypropoxy), the court held that KSR did not eliminate the lead compound requirement in chemical cases. Because the prior art taught that the lipophilic fluorinated trifluoroethoxy group was essential for anti-ulcer efficacy, a skilled artisan would not have been motivated to replace it with an unfluorinated, hydrophilic methoxypropoxy chain with a reasonable expectation of success.

In Bristol-Myers Squibb Co. v. Teva Pharmaceuticals USA, Inc., the Federal Circuit affirmed the obviousness invalidation of claim 8 of U.S. Patent No. 5,206,244 covering Baraclude (entecavir). Entecavir differs from the prior art antiviral lead compound 2'-CDG solely by an exocyclic methylene group at C5'. The court held that lead compound selection must be judged based on what was known to a skilled artisan at the priority date, barring patentees from using post-filing discoveries of toxicity to retroactively disqualify a lead compound. Furthermore, BMS could not rely on unexpected results against hepatitis B because the patent specification disclosed only general herpes virus activity and omitted hepatitis B.

In Aventis Pharma Deutschland GmbH v. Lupin, Ltd., the Federal Circuit reversed a district court validity judgment, holding that claim 1 of Aventis's U.S. Patent No. 5,061,722 covering Altace (ramipril) was invalid for obviousness under 35 U.S.C. 103. Ramipril contains five chiral stereocenters yielding thirty-two theoretical stereoisomers. While earlier prior art disclosed ramipril as a diastereomeric mixture, Aventis claimed the purified 5(S) stereoisomer. The Federal Circuit held that because prior art ACE inhibitors established that the all-(S) configuration was required for stereospecific coordination to catalytic zinc and active-site subpockets, isolating the active isomer from a known mixture was prima facie obvious without requiring an explicit prior art teaching to purify. Furthermore, Aventis could not show unexpected results because roughly doubling potency over an equimolar active-inactive diastereomeric mixture is chemically predictable.

In Merck Sharp & Dohme Corp. v. Hospira, Inc., the Federal Circuit affirmed that claims 21-34 of Merck's U.S. Patent No. 6,486,150 covering Invanz (ertapenem sodium for injection) were invalid for obviousness under 35 U.S.C. 103. Ertapenem exhibits two severe chemical degradation pathways in aqueous formulation: beta-lactam hydrolytic ring cleavage and intermolecular dimerization driven by nucleophilic attack of the secondary pyrrolidine amine on an adjacent molecule's beta-lactam carbonyl. While Merck stabilized the drug by reacting it with sodium bicarbonate to form a reversible carbamate adduct, the court held that because earlier prior art disclosed this chemical stabilization and broad pH window, the claimed multi-step manufacturing recipe was a routine engineering optimization. Furthermore, under the blocking patent doctrine, the court held that Invanz's commercial success could not establish non-obviousness because Merck's earlier compound patent blocked generic competition.

In Eagle Pharmaceuticals, Inc. v. Slayback Pharma LLC, the Federal Circuit affirmed that a patent applicant who discloses an unclaimed chemical alternative in the specification is legally barred from capturing that alternative under the doctrine of equivalents. The court affirmed judgment on the pleadings in favor of generic challenger Slayback Pharma, holding that Eagle dedicated ethanol to the public under the disclosure-dedication doctrine by naming it alongside propylene glycol as an organic solvent for stabilizing ready-to-dilute bendamustine liquid formulations in U.S. Patent Nos. 9,265,831; 9,572,797; 9,579,384; and 10,010,533. Because Eagle specifically claimed propylene glycol while leaving ethanol unclaimed, Slayback generic formulation utilizing ethanol did not infringe, establishing a critical precedent for pharmaceutical formulation design-arounds.

In Novartis Pharmaceuticals Corp. v. Accord Healthcare, Inc., the Federal Circuit held on rehearing that a negative claim limitation added during patent prosecution cannot satisfy the written description requirement of 35 U.S.C. 112(a) through mere silence in the specification. The court invalidated the asserted claims of Novartis's U.S. Patent No. 9,187,405 covering Gilenya (fingolimod, 0.5 mg daily for relapsing-remitting multiple sclerosis), holding that while the specification disclosed administering 0.5 mg daily, it contained zero mention of loading doses. Because silence does not establish that the inventor possessed a regimen specifically excluding an initial loading dose, the negative limitation 'absent an immediately preceding loading dose regimen' failed as a matter of law, clearing the market for generic filers including Intas and Accord Healthcare.

In UCB, Inc. v. Actavis Laboratories UT, Inc., the Federal Circuit affirmed the obviousness invalidation of claims 1-3 of U.S. Patent No. 10,130,589, covering UCB's reformulated Neupro (rotigotine) transdermal patch. Following a global market recall in 2008 triggered by the spontaneous nucleation of thermodynamically stable needle-like Form II rotigotine crystals in the silicone matrix, UCB incorporated polyvinylpyrrolidone (PVP) as a solid-state crystallization inhibitor at a rotigotine-to-PVP weight ratio between 9:1.5 and 9:5. The Federal Circuit held that because earlier patents already disclosed transdermal rotigotine patches with PVP across an overlapping ratio range (1:0.1 to 1:10), a prima facie presumption of obviousness applied. Uncovering the biophysical mechanism of Form II crystal inhibition was a newly discovered property of an already-known composition, which cannot confer patentability under Section 103 without demonstrating unexpected results across the entire claimed range.

For over forty years, intravenous minocycline was severely limited by injection-site phlebitis, vascular burning, and localized red blood cell hemolysis caused by the planar hydrophobic antibiotic intercalating into erythrocyte lipid bilayers. Melinta Therapeutics overcame this toxicological bottleneck by chelating minocycline with divalent magnesium at an unexpected molar ratio exceeding 4:1 at pH 4 to 6, shielding the aromatic rings without diminishing antibacterial efficacy. In Melinta Therapeutics, LLC v. Nexus Pharmaceuticals, Inc. (Fed. Cir. Appeal Nos. 2025-1281, 2025-1282, decided June 5, 2026), the Federal Circuit affirmed that Nexus infringed valid claims of U.S. Patent No. 9,084,802. The court rejected obviousness and indefiniteness challenges, holding that the prior art taught away from divalent metal addition due to precipitation and potency loss, and that overcoming four decades of formulation toxicity constituted a non-obvious breakthrough.

In Intra-Cellular Therapies, Inc. v. The Controller of Patents, the Delhi High Court delivered a landmark ruling clarifying the patentability of isotopic substitution under Indian patent law. Rejecting patent claims to deuterated analogs of the atypical antipsychotic lumateperone, the Court held that pharmacokinetic improvements and metabolic stability driven by the kinetic isotope effect do not establish enhanced therapeutic efficacy under Section 3(d), while affirming that species claims encompassed by an innovator's earlier genus disclosure cannot manufacture novelty through successive selections.

In Novo Nordisk A/S v. Dr. Reddy's Laboratories Ltd., the Delhi High Court refused to grant an interim injunction restraining Dr. Reddy's and OneSource from manufacturing and exporting generic semaglutide. Presided over by Justice Manmeet Pritam Singh Arora, the Court held that Dr. Reddy's raised a credible challenge to the validity of Novo Nordisk's species patent IN 262697 under the genus-species doctrine, Section 64(1)(a) prior claiming, and Section 3(d) of the Indian Patents Act, given Novo's earlier granted genus patent IN 275964. While maintaining the defendants' undertaking not to commercialize semaglutide in India prior to patent expiration on March 20, 2026, the Court held that manufacturing in India solely for export to non-infringing foreign jurisdictions causes no irreparable injury to the patentee and protects India's generic manufacturing base.

When a patentee acts as its own lexicographer by defining a chemical term in the specification, can it later argue that standard organic chemistry principles or claim context broaden that definition to capture a competitor's lipid? In Alnylam Pharmaceuticals, Inc. v. Moderna, Inc., the Federal Circuit held that explicit patent definitions strictly control claim scope. Because Alnylam defined 'branched alkyl' to require a carbon atom bound to at least three other carbon atoms, it could not assert infringement against Moderna's SM-102 ionizable lipid, whose alpha-branching carbon is bonded to only two carbon atoms and one ester oxygen.

In Bayer Pharma AG v. Mylan Pharmaceuticals Inc., the Federal Circuit held that adding the limitation 'clinically proven effective' to known drug dosing regimens is a functionally unrelated limitation that cannot confer patentability under 35 U.S.C. 102 or 103. The court invalidated claims 1-4 of Bayer's Xarelto (rivaroxaban) and aspirin patent, holding that subsequent clinical trial data from the COMPASS study does not transform the physical chemistry or administration of the drug combination. However, the court vacated the invalidation of claims 5-8, holding that 'first product comprising rivaroxaban and aspirin' requires a single fixed-dose combination dosage form rather than co-administration of separate tablets.

In Galderma Laboratories v. Lupin Inc., the Federal Circuit affirmed that Lupin's generic modified-release doxycycline capsules do not infringe Galderma's Oracea patents under either literal infringement or the doctrine of equivalents. The court held that FDA bioequivalence does not per se establish patent infringement, ruling that matching pharmacokinetic plasma profiles cannot substitute for proving that a generic formulation operates in substantially the same way as claimed release-rate architectures.

When generic challengers formulated alternative crystalline solid forms to navigate Entresto's multi-billion dollar patent thicket, Novartis asserted an unlisted patent directed to an amorphous supramolecular complex. But at the Federal Circuit, Novartis's Raman spectroscopy evidence crumbled under scrutiny: generic tableting never created the claimed amorphous entity.

In Allergan v. MSN Laboratories, the Federal Circuit established a landmark rule for pharmaceutical patent families: a first-filed, first-issued patent that earns Patent Term Adjustment cannot be invalidated for obviousness-type double patenting by its own later-filed, earlier-expiring continuation progeny.

In Salix v. Norwich, the Federal Circuit held that patent claims directed to crystalline Form beta of rifaximin were invalid as obvious over the 1986 Cannata prior art. The court rejected the argument that polymorph screening is inherently inventive, confirming that routine characterization of crystal habits obtained from disclosed solvent mixtures cannot support a separate patent monopoly.

Azurity Pharmaceuticals patented a drinkable liquid formulation of vancomycin hydrochloride to treat C. difficile infections, securing allowance only after repeatedly assuring the patent office that its formulation disclaimed polar organic solvents like propylene glycol to overcome prior art. When Indian generic manufacturer Alkem Laboratories formulated an ANDA product containing propylene glycol both as a co-solvent and in its flavoring agent, Azurity sued for infringement. The Federal Circuit affirmed a complete non-infringement win for Alkem, holding that sweeping prosecution disavowals cannot be clawed back through creative claim construction or pretrial stipulations.

Duke University and Allergan won a $39 million jury verdict accusing Sandoz of infringing their patent for using bimatoprost to grow hair. The Federal Circuit wiped out the verdict entirely, holding that reciting a generic prostaglandin carbon skeleton alongside branching categories of millions of substituent combinations provides zero written description for a specific subgenus when the specification contains no blaze marks pointing to that selection.

Purdue's abuse-deterrent OxyContin patent required curing tablets in a coating pan -- a device that had only ever been used to coat pills, never cure them. The Federal Circuit said that novelty of use is exactly what made the substitution obvious, clearing the way for Accord Healthcare, the U.S. arm of India's Intas Pharmaceuticals, to sell its generic.

Lupin's generic tolvaptan process uses more sodium borohydride than Otsuka's patent claims allow. The Federal Circuit still found no infringement, because a reaction's real endpoint is not the same as the total reagent poured into the flask - and Otsuka's own experimental data could not prove otherwise.

Wyeth's patent claimed any covalently-binding EGFR inhibitor at any calculated dose, but only disclosed in-vitro data for three compounds and dosage ranges that would poison patients at the levels the patent's own numbers implied. The Federal Circuit affirmed that this is not enablement, wiping out a $107.5 million jury verdict.

The Delhi High Court set aside the refusal of a sugammadex process patent because India's Patent Office skipped a hearing the Patents Act guarantees separately from a pre-grant opposition, and flagged, without deciding, that the obviousness rejection stacked four prior-art documents without saying why a chemist would combine them.

Actelion sued Mylan over its generic Veletri (epoprostenol), arguing pH should be measured at the solution's cold manufacturing temperature rather than standard lab conditions. The Federal Circuit disagreed, and Actelion lost its equivalents fallback on two separate, independent grounds tracing back to its own patent drafting choices.

The Federal Circuit affirmed that a patent claiming a reaction "at a pH between 7.0 and 9.0" requires that pH be maintained for the entire reaction step, not just touched briefly -- so Vifor's manufacturing process staying in range 90 percent of the time was, under that reading, still zero percent infringement.

The Federal Circuit affirmed that Exelixis's patents on crystalline cabozantinib (L)-malate, the active ingredient in the cancer drug Cabometyx, adequately describe an entire genus of crystalline salt forms even though the specification names only two of them by name. MSN Laboratories built its own, separately patented crystal form to work around the disclosed ones, conceded that its product still infringed, and lost its remaining argument: that the patent never really described what it was claiming.

A Federal Circuit ruling this year invalidated Enanta's coronavirus protease inhibitor patent because its 2020 provisional application described a substituent as a two-to-twelve-carbon range, while Pfizer's real Paxlovid compound uses a one-carbon version at that exact position.

Weeks after courts kept striking down broad antibody genus patents following the Supreme Court's Amgen v. Sanofi decision, the Federal Circuit went the other way for Teva's headache antibody patents against Eli Lilly's Emgality, and the difference comes down to exactly what was being claimed.

The Federal Circuit wiped out a 41.8 million dollar verdict against the makers of Enhertu because Seagen's original 2004 patent filing never actually disclosed a working example of the exact linker chemistry it later tried to claim, only the ingredients that could theoretically build it.

The Indian Patent Office rejected AbbVie's foundational patent application for venetoclax (Venclexta/Venclyxto), the Bcl-2 inhibitor behind a multi-billion-dollar leukemia franchise, after seven pre-grant oppositions spanning 2018 to 2025. The Deputy Controller found that a Markush genus claim covering thousands of sulfonamide compounds was backed by real inhibition data for only a handful of them, a chemistry problem, not a technicality, that also sank the claim under Section 3(d) and for insufficient disclosure.

A May 2026 Delhi High Court ruling on a fungicide crystal polymorph tested whether Section 3(d)'s efficacy standard, the same rule that decided the Glivec case, should apply the same way outside medicine. The court's answer keeps the pharma-specific bar exactly where Novartis left it.

After four pre-grant oppositions and fifteen years of prosecution, the Indian Patent Office granted Novartis and Astex a patent on ribociclib (Kisqali), a breast-cancer drug, and the chemistry arguments on both sides are worth examining honestly, not just the outcome.

The Controller rejected Array BioPharma's triple-drug combination on three separate grounds in one order: obviousness, Section 3(d), and method-of-treatment. The Delhi High Court set aside all three, not because the underlying law was wrong, but because the order never showed its work.

The Delhi High Court upheld the Patent Offices rejection of Intra Cellular Therapies patent application for deuterated variants of its own genus-patented compound family, holding that coverage under a Markush claim can anticipate a later species claim even where the genus patent never specifically discloses that exact compound. The Court separately rejected the applicants Section 3(d) evidence, finding that improved bioavailability in animal data did not by itself establish enhanced therapeutic efficacy over the known non-deuterated compound.