US Patent 11,951,101: Iptacopan PNH Method-of-Treatment Claims, Scope and Patent Landscape

US Patent No. 11,951,101 is a method-of-treatment patent directed to oral iptacopan, marketed as Fabhalta, for paroxysmal nocturnal hemoglobinuria (PNH). Its principal commercial claim covers administration of approximately 200 mg twice daily, expressed as anhydrous free-base equivalent. The claims are particularly relevant to patients previously treated with anti-C5 therapy, patients with residual anemia, and patients who achieve hemoglobin improvement without transfusion.

The patent is strategically important because its independent claim tracks the approved Fabhalta regimen. It does not primarily protect the chemical compound, a tablet composition, or a manufacturing process. Those protections must be assessed in separate patent families.

What drug and therapeutic regimen does US 11,951,101 protect?

The claimed active ingredient is iptacopan, chemically identified in the claims as:

4-((2S,4S)-(4-ethoxy-1-((5-methoxy-7-methyl-1H-indol-4-yl)methyl)piperidin-2-yl))benzoic acid

The claims cover the compound itself and pharmaceutically acceptable salts, including the hydrochloride salt. Fabhalta is supplied as iptacopan hydrochloride capsules, but the dose is calculated by reference to the amount of anhydrous free base.

Claim element	Scope
Disease	Paroxysmal nocturnal hemoglobinuria
Route	Oral administration
Dose	About 200 mg twice daily
Dose basis	Anhydrous free-base amount
Active ingredient	Iptacopan or pharmaceutically acceptable salt
Key salt embodiment	Iptacopan hydrochloride
Treatment population	Broad PNH population under claim 1; narrower subgroups in dependent claims
Primary therapeutic effect	Treatment of PNH, including hemoglobin improvement and control of hemolysis

The core commercial risk is concentrated in claim 1. A product that supplies iptacopan orally at 200 mg twice daily for PNH would closely correspond to the express limitations of that claim.

How are the 38 claims organized?

Only claim 1 is independent. Claims 2 through 38 depend directly or indirectly on claim 1 and add patient characteristics, biomarkers, treatment outcomes, vaccination status, or the hydrochloride salt.

Core regimen claim

Claim 1 requires all of the following:

A subject in need of PNH treatment.
Oral administration.
Iptacopan or a pharmaceutically acceptable salt.
Approximately 200 mg twice daily.
Dose calculation based on anhydrous free base.
Treatment of PNH.

The claim is a treatment-method claim rather than a product claim. It is directed to conduct by a healthcare provider, patient, or other party administering the claimed regimen.

Prior anti-C5 therapy and residual anemia

Claims 2 and 3 narrow the population to patients previously treated with anti-C5 therapy, including anti-C5 monoclonal antibodies. This captures patients transitioning from therapies such as eculizumab or ravulizumab.

Claim 4 covers patients with residual anemia. This is commercially relevant because residual anemia is a recognized treatment problem in PNH patients receiving terminal complement inhibition. Iptacopan acts upstream by inhibiting factor B and can address both intravascular and extravascular hemolysis.

Baseline laboratory criteria

Claims 5 and 6 require evaluation of laboratory parameters before treatment. Claim 6 narrows the population to subjects with hemoglobin of approximately 10 g/dL or less.

The listed laboratory parameters are:

Hemoglobin
Haptoglobin
Reticulocytes
Bilirubin

The pre-treatment assessment limitation may create factual disputes in infringement cases. A generic product using the same approved indication and standard clinical monitoring could still face infringement allegations, but the patentee would need to establish that the claimed baseline evaluation occurred where a dependent claim is asserted.

Treatment outcomes

Claims 7 through 18 cover clinical outcomes and disease mechanisms, including:

Increased hemoglobin
Normalization of intravascular hemolysis
Normalization of extravascular hemolysis
Increased haptoglobin
Reduced reticulocytes
Reduced bilirubin
Treatment of PNH-associated hemolysis
Reduced C3 deposition
Increased red-blood-cell survival
Reduced fragment Bb
Hemoglobin increase of approximately 2 g/dL or more
Sustained hemoglobin increase
Sustained hemoglobin of at least approximately 12 g/dL
Hemoglobin improvement without RBC transfusion
Treatment of patients who have received RBC transfusions

These claims are narrower than claim 1 because they require a specified result or patient history. Claims requiring a clinical outcome may be harder to enforce at the point of product launch because the outcome occurs after administration. They remain relevant to induced-infringement and clinical-use theories, particularly where prescribing materials, trial protocols, or treatment guidelines encourage the claimed outcome.

Vaccination limitation

Claim 19 requires prior vaccination against Neisseria meningitidis types A, C, Y, and W-135. Claims 30, 32, 34, and 37 incorporate this limitation into narrower combinations.

The vaccination limitation reflects the infection risk associated with complement pathway inhibition. It may align with the FDA label and standard risk-management practice, but it does not appear in the broad independent claim. A product could therefore fall within claim 1 even if a particular patient had not satisfied the vaccination limitation in claim 19.

Hydrochloride salt claims

Claims 22 through 28 and 35 through 38 specify oral administration of iptacopan hydrochloride. These claims are closely aligned with the commercial dosage form.

The hydrochloride claims provide fallback positions if a court construes claim 1 narrowly or if a challenger contests the scope of “pharmaceutically acceptable salt.” They also reduce the practical relevance of a design-around based on use of another salt, although other salt forms could avoid claims expressly limited to hydrochloride.

What is the strongest infringement position under US 11,951,101?

The strongest literal infringement case would involve:

Fabhalta or an equivalent iptacopan hydrochloride product;
Oral administration;
PNH treatment;
200 mg twice daily;
Dose stated or calculated as 200 mg of anhydrous free base;
Use in the FDA-approved population.

The commercial product appears to align directly with the central limitations of claim 1 and the hydrochloride limitations in dependent claims 22 and related claims.

A generic applicant seeking approval for the same PNH indication and dose would face greater risk than an applicant with a restricted label or different proposed use. FDA approval alone does not adjudicate patent validity or infringement, but the proposed label is central to induced-infringement analysis.

When does US Patent 11,951,101 expire?

The patent issued on April 9, 2024. Its expiration date must be determined from the earliest effective nonprovisional or PCT filing date, terminal disclaimers, patent-term adjustment, and any patent-term extension.

Based on the patent’s priority structure, the base 20-year term is expected to fall in 2039, subject to the official USPTO term calculation. The operative date should be confirmed against the USPTO patent-term data and any Orange Book listing.

Event	Date or status
Patent	US 11,951,101
Issue date	April 9, 2024
Expected base term	2039, subject to official adjustment
Patent-term adjustment	Must be checked in USPTO records
Patent-term extension	No extension is established from the claim information provided
Terminal disclaimer	Must be checked in the file history
Earliest practical generic exposure	Potentially before patent expiry through Paragraph IV litigation or settlement

The patent’s expiration date is not necessarily the same as the end of FDA regulatory exclusivity.

What is the FDA exclusivity status of Fabhalta?

Fabhalta was approved by FDA on December 5, 2023, for adults with PNH. The relevant regulatory protections are separate from US 11,951,101.

Protection	Expected period
New chemical entity exclusivity	Generally five years from approval, subject to Paragraph IV timing rules
Expected NCE endpoint	December 5, 2028
Orphan-drug exclusivity	Generally seven years from approval for the designated indication
Expected orphan endpoint	December 5, 2030
Patent protection	Extends independently and may continue beyond regulatory exclusivity

FDA NCE exclusivity blocks submission of an ANDA or 505(b)(2) application for the same active moiety during the protected period, subject to statutory exceptions. Orphan exclusivity blocks approval of the same drug for the same orphan indication during the seven-year period, with statutory exceptions.

What is the Orange Book status of US 11,951,101?

Fabhalta’s Orange Book position must be evaluated at the product level, not solely from the patent number. A listed patent may cover:

The active ingredient;
A formulation;
A method of use;
A dosage regimen;
A specific patient population.

US 11,951,101 is a method-of-use patent based on the claims supplied. If listed for Fabhalta, it would likely be identified as a use patent rather than a compound or formulation patent.

An Orange Book listing can trigger a Paragraph IV certification by an ANDA applicant. The listing does not establish validity or infringement. A patent may be challenged through:

Paragraph IV certification;
Declaratory judgment;
Inter partes review;
Post-grant review where statutory timing permits;
District-court invalidity and noninfringement defenses.

Which claims are most vulnerable to invalidity challenges?

The claims are vulnerable on different grounds depending on the asserted limitation.

Obviousness

The principal obviousness issue would be whether prior art made it obvious to administer iptacopan at approximately 200 mg twice daily for PNH, particularly in patients with residual anemia after anti-C5 therapy.

Potential prior-art categories include:

Earlier iptacopan compound and factor-B inhibitor patents;
PNH treatment disclosures;
Clinical trial protocols;
Dose-ranging studies;
Prior art describing extravascular hemolysis;
Publications involving patients inadequately controlled by C5 inhibition.

The specific 200 mg twice-daily regimen and demonstrated hemoglobin response may support a nonobviousness position if the prior art did not reasonably predict the clinical result.

Written description and enablement

The patent must support the claimed regimen and the broad range of outcomes. Potential disputes may concern:

Whether the specification supports all pharmaceutically acceptable salts;
Whether the disclosure enables every claimed PNH population;
Whether the specification supports sustained hemoglobin normalization;
Whether the clinical outcomes are adequately tied to the claimed dose.

Claims 14 through 17 and related claims are narrower but may invite scrutiny over the evidentiary support for the specified hemoglobin outcomes.

Indefiniteness

Potential construction issues include:

“About 200 mg”
“Sustained increase”
“Normalizing” hemolysis
“Residual anemia”
“As compared to baseline”
“Subject in need thereof”

The use of “about” is common in pharmaceutical claims, but the specification and prosecution history will determine the permissible range. The patent’s claim construction may distinguish between the amount of iptacopan hydrochloride salt and the anhydrous free-base equivalent.

Does US 11,951,101 cover formulations or manufacturing?

No. The supplied claims are not composition-of-matter, formulation, crystalline-form, tablet, capsule, or manufacturing claims.

They do not expressly claim:

A tablet composition;
Capsule excipients;
A particular polymorph;
A crystalline form;
A salt preparation process;
A synthetic intermediate;
A purification process;
A drug-product coating;
A release profile.

Those rights may exist in related patents. A complete freedom-to-operate analysis for a generic or licensee would require review of the broader iptacopan patent family, including composition, solid-state, formulation, process, and method-of-use applications.

How does the patent compare with competing PNH therapies?

Product	Active ingredient	Target	Administration	Relevance to US 11,951,101
Fabhalta	Iptacopan	Factor B	Oral, 200 mg twice daily	Directly aligned with the claimed regimen
Soliris	Eculizumab	C5	Intravenous	Prior anti-C5 therapy referenced in claims 2 and 3
Ultomiris	Ravulizumab	C5	Intravenous	Prior anti-C5 therapy referenced in claims 2 and 3
Empaveli	Pegcetacoplan	C3	Subcutaneous	Competing complement therapy; not expressly named
Voydeya	Danicopan	Factor D	Oral adjunct therapy	Competing proximal complement approach, generally used with C5 inhibition

Iptacopan’s differentiation is oral factor-B inhibition and control of both intravascular and extravascular hemolysis. The patent claims target the clinical use case of improving anemia and hemolysis in PNH, including patients who remain inadequately controlled with anti-C5 treatment.

What generic launch risks exist?

A generic launch would face four principal barriers.

Regulatory timing

NCE and orphan exclusivity may delay ANDA or 505(b)(2) approval, depending on the application route and proposed indication.

Orange Book patents

A listed method-of-use patent could require a Paragraph IV certification or a section viii statement carving out the patented use. A section viii strategy may be difficult if the approved label and commercial use are inseparable from the claimed PNH regimen.

Litigation

A Paragraph IV notice could trigger a 30-month stay if the patent owner files suit within the statutory period. The central dispute would likely focus on:

Validity of the dose regimen;
Obviousness based on prior clinical and dose-ranging disclosures;
Construction of “about 200 mg”;
Whether use of the hydrochloride salt infringes;
Whether a proposed generic label induces the claimed treatment.

Substitution and commercial execution

Even after patent clearance, a generic would need to address FDA substitution, payer coverage, physician adoption, and competition from other complement inhibitors. The oral route could make iptacopan commercially attractive, but the market includes established anti-C5 products and other proximal complement inhibitors.

Are there biosimilar risks for Fabhalta?

No conventional biosimilar pathway applies because Fabhalta is a small-molecule drug, not a biologic. The relevant competitors are ANDA generics or potentially 505(b)(2) applicants.

The absence of biosimilar exposure does not eliminate competition risk. Generic applicants can challenge method-of-use, formulation, compound, or process patents through the Hatch-Waxman framework.

What licensing or settlement issues affect the patent?

The claim information does not establish a license, covenant not to sue, Paragraph IV settlement, or authorized-generic agreement concerning US 11,951,101.

The commercial owner of Fabhalta is Novartis. Any definitive assessment of licensing or settlement exposure must distinguish:

Originator ownership;
Patent-family ownership;
In-licensed patents;
Co-development rights;
Generic settlements;
Authorized-generic arrangements.

No settlement terms should be inferred solely from the patent claims or FDA approval record.

What is the geographic coverage?

US 11,951,101 provides protection only in the United States. It does not directly control:

European Union sales;
United Kingdom sales;
Canadian sales;
Japanese sales;
Australian sales;
Manufacturing outside the United States;
Importation into the United States where applicable.

Equivalent PNH method-of-treatment claims may exist in foreign national-phase patents, but each jurisdiction requires separate review of claim scope, validity, prosecution amendments, term, supplementary protection certificates, and local enforcement rules.

How strong is the patent estate?

US 11,951,101 is commercially strong against a product that follows the Fabhalta label because claim 1 appears to track the approved indication, route, and dose. Its weaknesses are structural rather than commercial:

It is a use patent, not a composition-of-matter patent.
The dependent claims require additional facts that may not exist for every patient.
Clinical-outcome claims may be difficult to prove at launch.
“About,” “sustained,” and “normalizing” create claim-construction issues.
A generic could pursue a restricted label or challenge validity.
Related compound, formulation, solid-state, and process patents may determine the actual launch date.

Patent-strength assessment

Factor	Assessment
Alignment with approved product	Strong
Direct read-on by labeled 200 mg b.i.d. use	Strong
Protection of chemical entity	Not established by these claims
Protection of formulation	Not established by these claims
Dependence on patient conduct	High
Vulnerability to dose-regimen obviousness challenge	Material
Biosimilar exposure	None; small molecule
Generic exposure	Material after regulatory exclusivity and patent challenges
Geographic reach	United States only
Manufacturing barrier from this patent	Limited

Key Takeaways

US 11,951,101 is a PNH method-of-treatment patent covering oral iptacopan at approximately 200 mg twice daily.
The claims expressly use the anhydrous free-base amount, which is important for dosing the hydrochloride salt.
Claim 1 is the principal commercial claim and closely tracks the Fabhalta regimen.
Dependent claims target prior anti-C5 therapy, residual anemia, low baseline hemoglobin, hemolysis biomarkers, transfusion-free response, and meningococcal vaccination.
The patent does not, based on the supplied claims, protect iptacopan’s chemical structure, formulation, solid form, or manufacturing process.
Fabhalta’s FDA exclusivity and the patent term are separate barriers. Expected regulatory endpoints are December 2028 for NCE exclusivity and December 2030 for orphan exclusivity, subject to statutory exceptions.
Generic competition would most likely proceed through an ANDA with Paragraph IV or section viii strategies.
No conventional biosimilar pathway applies.
The strongest infringement case concerns a generic label reproducing oral iptacopan 200 mg twice daily for PNH.
The broader launch analysis requires the full US and foreign patent families covering the compound, salt, solid form, formulation, manufacturing process, and additional PNH uses.

FAQs

What is the active ingredient protected by US 11,951,101?

The claims cover iptacopan, including pharmaceutically acceptable salts and specifically iptacopan hydrochloride in dependent claims.

Does US 11,951,101 cover Fabhalta tablets or capsules?

The supplied claims do not claim a tablet, capsule, excipient system, or specific formulation. They cover oral administration of the active ingredient at the claimed dose.

Can a generic avoid US 11,951,101 by using a different iptacopan salt?

A different salt may avoid claims expressly limited to iptacopan hydrochloride, but claim 1 broadly covers pharmaceutically acceptable salts. The outcome would depend on claim construction and the dose expressed as anhydrous free base.

Does prior treatment with eculizumab have to be present for claim 1?

No. Prior anti-C5 therapy is required only by dependent claims 2 and 3. Claim 1 covers the broader PNH treatment method.

Is a 200 mg once-daily regimen within the patent?

The express claim requires approximately 200 mg twice daily. A once-daily regimen would not literally satisfy the twice-daily limitation, although infringement analysis could consider claim construction and the doctrine of equivalents.

References

U.S. Patent No. 11,951,101. (2024). Methods of treating paroxysmal nocturnal hemoglobinuria. United States Patent and Trademark Office.
U.S. Food and Drug Administration. (2023). FDA approves new treatment for adults with paroxysmal nocturnal hemoglobinuria. FDA.
U.S. Food and Drug Administration. (2023). Fabhalta (iptacopan) prescribing information. Novartis Pharmaceuticals Corporation.
U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations. FDA, Center for Drug Evaluation and Research.
United States Code, 21 U.S.C. §§ 355, 360cc.
United States Code, 35 U.S.C. §§ 154, 271, 282, 315, 321.

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate
Novartis	FABHALTA	iptacopan hydrochloride	CAPSULE;ORAL	218276-001	Dec 5, 2023		RX	Yes	Yes	11,951,101	⤷ Start Trial				TREATMENT OF PAROXYSMAL NOCTURNAL HEMOGLOBINURIA (PNH) BY ADMINISTRATION OF 200 MG OF IPTACOPAN TWICE DAILY	⤷ Start Trial
>Applicant	>Tradename	>Generic Name	>Dosage	>NDA	>Approval Date	>TE	>Type	>RLD	>RS	>Patent No.	>Patent Expiration	>Product	>Substance	>Delist Req.	>Patented / Exclusive Use	>Submissiondate

Summary for Patent: 11,951,101