Details for Patent: 11,306,106

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Which drugs does patent 11,306,106 protect, and when does it expire?

Patent 11,306,106 protects XOFLUZA and is included in two NDAs.

This patent has thirty-nine patent family members in twenty-three countries.

Summary for Patent: 11,306,106

Title:	Pharmaceutical compositions containing substituted polycyclic pyridone derivatives and prodrug thereof
Abstract:	The present invention provides a pharmaceutical composition containing the following compound having antiviral action: wherein each of the symbols is defined in the specification.
Inventor(s):	Makoto Kawai
Assignee:	Shionogi and Co Ltd
Application Number:	US16/937,877
Patent Litigation and PTAB cases:	See patent lawsuits and PTAB cases for patent 11,306,106
Patent Claim Types: see list of patent claims	Use; Delivery; Dosage form;

US Patent 11,306,106: Baloxavir Marboxil Crystal-Form Claims, Exclusivity and Patent Landscape

US Patent 11,306,106 protects methods of treating or preventing influenza with specified crystalline forms of baloxavir marboxil, the active pharmaceutical ingredient in Xofluza. The patent does not broadly claim the baloxavir molecule, every formulation, or every manufacturing process. Its commercial value is concentrated in solid-state form protection covering Forms I, II and III, particularly the Form I material used in marketed Xofluza tablets.

The patent was issued to Shionogi & Co., Ltd. and has a stated expiration date of March 19, 2038, subject to any applicable patent-term adjustment or other statutory modification.[1] Its claims are method-of-treatment claims, creating infringement exposure primarily for a generic applicant that markets a product containing a claimed crystal form for the patented influenza indications.

What drug and crystal forms does US Patent 11,306,106 protect?

US 11,306,106 covers baloxavir marboxil, an orally administered cap-dependent endonuclease inhibitor. Xofluza is marketed by Roche’s Genentech unit in the United States under a license and collaboration arrangement with Shionogi.[2,3]

The patent identifies three crystalline forms by X-ray powder diffraction, or XRPD, peak patterns:

Crystal form	Claimed XRPD peaks, 2θ	Practical significance
Form I	8.6°, 14.1°, 17.4°, 20.0°, 24.0°, 26.3°, 29.6°, 35.4°	Principal form associated with marketed 20 mg and 40 mg tablets
Form II	4.4°, 8.9°, 11.7°, 14.9°, 22.3°, 24.4°, 28.0°, 31.5°	Alternative claimed solid form
Form III	4.4°, 8.7°, 10.6°, 17.3°, 17.5°, 22.0°, 24.0°, 24.1°, 31.0°	Alternative claimed solid form

The independent claims require administration of “a crystal” of the compound having two or more specified XRPD peaks. The dependent claims require the full listed peak set for each form.

The patent therefore protects the use of identified solid-state forms rather than merely protecting a chemical formula. A product containing baloxavir marboxil in one of the claimed forms may fall within the patent even if its excipients, tablet shape, packaging, manufacturing site and commercial name differ from Xofluza.

How broad are the independent claims in US 11,306,106?

Claims 1, 20 and 39 are the principal independent claims. They cover:

Independent claim	Protected use	Covered crystal forms
Claim 1	Treatment of a disease caused by a virus having cap-dependent endonuclease	Forms I, II and III
Claim 20	Treatment of influenza	Forms I, II and III
Claim 39	Prevention of influenza	Forms I, II and III

Claim 1 is technically broader than claims 20 and 39 because it refers to a disease caused by a virus having cap-dependent endonuclease. Claim 20 is limited to influenza treatment. Claim 39 is limited to influenza prevention.

The claims use “comprising,” which generally permits additional treatment steps or product components unless those additions create a separate claim limitation. The claims do not require:

• a specific excipient;
• a particular tablet coating;
• a particular manufacturing process;
• a specified plasma concentration;
• a particular influenza strain;
• combination therapy;
• administration within a defined number of hours after symptom onset; or
• a specific commercial product name.

The core infringement question is whether the administered baloxavir marboxil material satisfies the claimed XRPD limitations and whether the accused use is treatment or prevention of the claimed disease.

What do the dependent claims add?

The dependent claims create narrower positions based on crystal form, route, dose, dosage form and patient age.

Form-specific claims

Claims 2 through 19 depend from claim 1. Claims 21 through 38 depend from claim 20. Claims 40 through 57 depend from claim 39.

Each claim group repeats the same structure:

1. The crystal must be Form I, II or III.
2. The crystal may be administered orally.
3. Administration may occur as a single dose.
4. The dose may be 40 mg or 80 mg.
5. The dose may range from 5 mg to 40 mg depending on body weight.
6. A 40 mg dose may be supplied as two 20 mg tablets.
7. The patient may be a human aged 12 years or older.

The claim architecture is repetitive. It produces multiple fallback combinations but does not create independent protection for each dosage strength or tablet configuration. The dose and age limitations appear in dependent claims and do not restrict the broadest independent claims.

Commercially relevant claim combinations

The most commercially relevant combinations are:

• Form I, oral, single-dose administration;
• Form I, 40 mg or 80 mg;
• Form I, 40 mg as two 20 mg tablets;
• Form I, treatment of influenza in a human aged 12 or older;
• Form I, prevention of influenza;
• the corresponding Form II and Form III combinations.

Form I is likely the central commercial concern because Xofluza tablets are identified in FDA labeling as containing baloxavir marboxil and are administered as a single oral dose.[4]

What is the strongest infringement theory against a generic Xofluza product?

The strongest theory would generally be induced infringement of a method claim based on the generic product’s labeling, combined with proof that the product contains a claimed crystal form.

A generic applicant could face risk if its proposed labeling instructs patients or physicians to:

• treat uncomplicated influenza;
• prevent influenza after exposure;
• administer a single oral dose; or
• use a 40 mg or 80 mg dose.

A product label that directs use for influenza treatment or post-exposure prophylaxis can provide evidence relevant to induced infringement even if the generic manufacturer does not administer the drug itself. The patent’s method claims are therefore commercially meaningful despite not claiming the tablet as a product.

The technical evidence would likely focus on:

• XRPD testing of the active ingredient;
• polymorph identity and conversion during processing;
• batch-to-batch solid-state specifications;
• whether the final tablet contains Form I, II or III;
• whether the claimed peak threshold is met; and
• whether the selected peaks are inherent in the accused material.

A generic manufacturer that uses a different polymorph, amorphous baloxavir marboxil, a different salt or a different prodrug could reduce literal infringement risk. That design-around strategy would require independent regulatory and pharmaceutical-development support because changing the solid form can affect stability, dissolution, bioavailability and manufacturing performance.

How does the XRPD language affect patent scope?

The XRPD limitations are both a source of protection and a potential validity or infringement battleground.

The independent claims require “two or more peaks” selected from a listed group. On its face, that language is broader than requiring the complete diffraction pattern for a form. A material could potentially satisfy an independent claim with only two qualifying peaks, while dependent claims 2, 8 and 14, and their counterparts, require the complete enumerated peak set.

The ±0.2° tolerance defines the claimed diffraction-angle range. Disputes could concern:

• instrument calibration;
• sample preparation;
• peak resolution;
• polymorph mixtures;
• preferred-orientation effects;
• peak intensity and signal-to-noise;
• whether two peaks are genuinely present; and
• whether the accused batch contains a mixture of crystal forms.

A patent challenger could target written description, enablement, indefiniteness or anticipation. The key technical issue would be whether the specification adequately supports the full scope of “two or more” peak combinations and whether the claimed forms were distinguishable from known baloxavir solids at the priority date.

When does US Patent 11,306,106 lose exclusivity?

Event	Date or status
US patent grant	April 19, 2022
Earliest relevant priority date	March 19, 2018
Stated expiration	March 19, 2038
Post-grant exclusivity	Patent rights generally continue until expiration unless invalidated, disclaimed or otherwise terminated
Generic launch before expiry	Requires a successful challenge, noninfringing design, license, settlement authorization or other legal basis

The relevant patent-term baseline is 20 years from the earliest effective nonprovisional or international filing date, not 20 years from grant. The March 19, 2038 date corresponds to a March 19, 2018 priority or filing framework reflected in public patent records.[1]

The patent should be analyzed together with the basic baloxavir compound patent and other Xofluza-related patents. A generic applicant may overcome US 11,306,106 but remain blocked by an earlier-expiring compound or formulation patent.

What is the Orange Book status of US 11,306,106?

US 11,306,106 is associated with the Xofluza patent estate and is relevant to FDA-listed patent analysis for NDA 210854. The FDA Orange Book identifies patents submitted by an NDA holder for an approved drug product, including patents covering the drug substance, drug product or method of use.[5]

The legal effect depends on the type of listing:

• A drug-substance or drug-product patent can create a direct product-related barrier.
• A method-of-use patent can be relevant to labeling and induced-infringement theories.
• A use code can narrow the FDA-listed indication associated with the patent.
• A Paragraph IV certification can trigger statutory litigation and, if timely sued, a 30-month stay of approval.

US 11,306,106 is particularly important as a method patent because its claims expressly cover influenza treatment and prevention. A generic applicant would need to evaluate whether a proposed label carves out the patented use or whether the remaining label still encourages use within claims 20 or 39.

Which Paragraph IV challenges affect Xofluza?

A Paragraph IV certification asserts that a listed patent is invalid, unenforceable or will not be infringed by the proposed generic product. For Xofluza, a Paragraph IV filing directed at US 11,306,106 would likely focus on the XRPD crystal-form limitations and the method-of-use provisions.

The likely challenge theories include:

Challenge theory	Application to US 11,306,106
Noninfringement	The generic uses a nonclaimed polymorph, amorphous material or different XRPD profile
Anticipation	A prior publication discloses the same baloxavir crystal form and claimed use
Obviousness	A skilled person would have selected or produced the claimed forms with a reasonable expectation of success
Written description	The specification does not support every two-peak combination in the independent claims
Enablement	The full crystal-form and treatment scope cannot be practiced without undue experimentation
Indefiniteness	Peak-selection language or XRPD tolerances fail to provide adequate claim certainty
Label carve-out	The proposed label excludes a patented indication, if FDA and patent-law requirements permit

No specific Paragraph IV litigation outcome is established by the claim text supplied. A definitive litigation-status conclusion requires the current FDA Orange Book, ANDA litigation dockets and district-court filings.

What patent litigation affects baloxavir marboxil?

The most probable litigation pressure points are:

1. Polymorph identification.
2. Whether the marketed or generic active ingredient contains Form I.
3. Whether Forms II and III are stable or convert into Form I.
4. Whether a generic label induces treatment or prevention use.
5. Whether the claims are invalid for obviousness or inadequate support.
6. Whether an authorized generic or settlement agreement controls launch timing.

A patent case involving US 11,306,106 would likely require coordinated patent, regulatory and analytical chemistry evidence. The technical record would include XRPD, differential scanning calorimetry, thermogravimetric analysis, solid-state nuclear magnetic resonance and stability data.

No settlement terms should be inferred from the patent grant or the claim set. A settlement could authorize an earlier launch without invalidating the patent, but the date and conditions would depend on the agreement and any required antitrust or regulatory disclosures.

How does US 11,306,106 compare with other Xofluza patents?

Patent category	Typical subject matter	Commercial effect
Core compound patent	Baloxavir or related chemical entities	Broadest chemical protection; usually central to earliest exclusivity
Crystal-form patent	Forms I, II and III of baloxavir marboxil	Protects selected solid-state materials and uses
Formulation patent	Tablets, excipients, dissolution or stability	Can restrict specific product designs
Method-of-use patent	Influenza treatment or prevention	Creates labeling and induced-infringement exposure
Manufacturing patent	Synthesis, crystallization or purification	Can restrict production routes or intermediates

US 11,306,106 is narrower than a compound patent but can be harder to avoid if the claimed Form I is the most stable, manufacturable or bioavailable form. A generic manufacturer cannot rely on a different tablet design if the active pharmaceutical ingredient still matches a claimed crystal form and the label instructs a claimed use.

Does baloxavir face biosimilar risk?

No. Baloxavir marboxil is a chemically synthesized small molecule, not a biologic. The relevant competitive pathway is an ANDA for a generic drug, not a biosimilar application under the Biologics Price Competition and Innovation Act.

The main regulatory and patent issues are therefore:

• pharmaceutical equivalence;
• bioequivalence;
• active-ingredient polymorph;
• method-of-use patent certification;
• labeling strategy;
• manufacturing control; and
• possible 30-month litigation stay.

A generic applicant may need to demonstrate that its active ingredient and finished product meet the relevant pharmaceutical and bioequivalence standards while avoiding the claimed crystal forms or obtaining authorization to launch.

What manufacturing and IP barriers does the patent create?

The patent creates a solid-state manufacturing barrier when a commercial process naturally produces Form I, II or III. Crystallization conditions can determine the resulting form. Relevant process variables include solvent, temperature, cooling rate, seeding, agitation, drying and humidity.

A design-around process may use:

• a nonclaimed polymorph;
• an amorphous dispersion;
• a different salt or prodrug;
• a different crystallization route that produces a nonclaimed form; or
• a formulation that changes the solid-state identity.

Those approaches may introduce separate barriers. A nonclaimed form could have inferior stability or dissolution. An amorphous material could recrystallize during storage. A different salt could require new clinical or regulatory support. The patent’s practical strength therefore depends on whether Forms I, II and III are commercially replaceable.

How strong is the patent estate for baloxavir?

US 11,306,106 has moderate-to-strong commercial relevance but narrower legal breadth than a core compound patent.

Its strengths are:

• coverage of three identified crystal forms;
• direct linkage to influenza treatment and prevention;
• coverage of single-dose oral administration;
• alignment with the commercial Xofluza dosing model;
• multiple dependent-claim fallback positions; and
• technical limitations that can be tested analytically.

Its weaknesses are:

• method-of-use rather than composition claims;
• reliance on XRPD evidence;
• potential design-around through a different solid form;
• possible challenges to the “two or more peaks” construction;
• dependence on label-based infringement theories; and
• limited relevance to uses outside the claimed diseases.

The strongest portfolio position arises when the core compound patent, crystal-form patent, formulation patent and method-of-use patent overlap through the same commercial product.

What generic launch scenarios exist for Xofluza?

Scenario	Likely consequence
Generic uses Form I and seeks approval for treatment and prevention	High infringement exposure under claims 20 and 39
Generic uses Form I but carves out prevention	Treatment claims remain relevant
Generic uses Form II or Form III	Claims expressly cover those forms
Generic uses an unclaimed polymorph	Lower literal infringement risk, subject to testing and other patents
Generic uses amorphous baloxavir marboxil	Potential design-around, with formulation and stability risks
Generic wins Paragraph IV litigation	Launch may occur before March 19, 2038, subject to other patents
Generic settles with patent holder	Launch timing depends on settlement terms
Authorized generic launches	Commercial entry may occur without eliminating the patent

A generic launch before March 2038 is most likely to depend on a successful noninfringement or validity position, a license, a settlement, or a product that does not use the patented forms or claimed indications.

What licensing deals affect baloxavir marboxil?

Shionogi entered into a collaboration with Roche for development and commercialization of baloxavir marboxil outside Japan and Taiwan. Roche commercializes Xofluza in the United States through Genentech.[2,3]

The licensing arrangement affects commercial control, but it does not change the patent scope. Shionogi remains the originating patent holder associated with the baloxavir program, while Roche’s rights support development, regulatory filings and commercialization in licensed territories.

What geographic coverage does the patent provide?

US 11,306,106 provides rights only in the United States. Corresponding foreign applications may protect related crystal forms or uses in other jurisdictions, but foreign claim scope, grant status and expiration dates must be assessed separately.

The relevant geographic questions are:

• whether a counterpart patent was granted in Europe;
• whether Japan and Taiwan have separate Shionogi-controlled rights;
• whether China and South Korea have enforceable crystal-form claims;
• whether Canadian and Australian patents cover the same XRPD forms; and
• whether local regulatory-use exemptions limit enforcement against generic development.

A US patent does not block manufacture, sale or use outside the United States unless a separate foreign patent applies.

Key Takeaways

• US 11,306,106 protects baloxavir marboxil crystal Forms I, II and III.
• Claims 1, 20 and 39 cover treatment of cap-dependent-endonuclease viral disease, influenza treatment and influenza prevention.
• The patent’s commercial center is Form I in single-dose oral Xofluza therapy.
• Dependent claims cover full XRPD peak patterns, 40 mg and 80 mg doses, 5 to 40 mg weight-based dosing, two 20 mg tablets and patients aged 12 years or older.
• The stated US expiration date is March 19, 2038.
• The patent is a method-of-use and crystal-form patent, not a broad claim to every baloxavir product.
• Generic risk will turn on XRPD identity, label language, Paragraph IV strategy and the remaining Xofluza patent portfolio.
• Baloxavir is a small molecule and faces generic, not biosimilar, competition.
• Form II and Form III are expressly claimed, so switching away from Form I alone does not avoid the patent.
• A nonclaimed polymorph or amorphous form may offer a design-around but can create stability, dissolution and regulatory risks.

FAQs About US Patent 11,306,106 and Xofluza

Is US 11,306,106 a composition-of-matter patent?

No. It claims methods of administering specified crystalline forms of baloxavir marboxil. It does not broadly claim the underlying baloxavir molecule in the manner of a core compound patent.

Does the patent cover Xofluza 20 mg tablets?

Potentially yes. The claims expressly cover a 40 mg dose administered as two 20 mg tablets, provided the administered material satisfies the claimed crystal-form limitations and the use falls within the relevant method claim.

Can a generic avoid US 11,306,106 by using Form II instead of Form I?

Not based on this patent alone. Forms I, II and III are each expressly claimed. A generic would need to use a nonclaimed material or establish that its use does not satisfy the applicable treatment or prevention claims.

Does the patent cover influenza prophylaxis?

Yes. Claim 39 and its dependent claims cover preventing influenza with the claimed crystal forms. Claims 40 through 57 provide narrower form, dose, route and patient limitations.

Is a biosimilar application relevant to Xofluza?

No. Baloxavir marboxil is a small molecule. FDA competition would ordinarily proceed through the ANDA generic-drug pathway rather than the biosimilar pathway.

Sources:

1. United States Patent and Trademark Office. (2022). US Patent No. 11,306,106, Crystals of baloxavir marboxil.
2. Hoffmann-La Roche Ltd. (2016). Roche and Shionogi enter into agreement for baloxavir marboxil.
3. Genentech. (2024). Xofluza (baloxavir marboxil) prescribing information.
4. U.S. Food and Drug Administration. (2024). Xofluza drug label and regulatory history.
5. U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations: Orange Book.

Drugs Protected by US Patent 11,306,106

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate
Genentech Inc	XOFLUZA	baloxavir marboxil	FOR SUSPENSION;ORAL	214410-001	Nov 23, 2020		RX	Yes	Yes						METHOD FOR TREATING INFLUENZA
Genentech Inc	XOFLUZA	baloxavir marboxil	FOR SUSPENSION;ORAL	214410-001	Nov 23, 2020		RX	Yes	Yes						METHOD FOR POST-EXPOSURE PROPHYLAXIS OF INFLUENZA
Genentech Inc	XOFLUZA	baloxavir marboxil	FOR SUSPENSION;ORAL	214410-002	May 30, 2025		RX	Yes	No						METHOD FOR POST-EXPOSURE PROPHYLAXIS OF INFLUENZA
Genentech Inc	XOFLUZA	baloxavir marboxil	FOR SUSPENSION;ORAL	214410-002	May 30, 2025		RX	Yes	No						METHOD FOR TREATING INFLUENZA

Foreign Priority and PCT Information for Patent: 11,306,106

Foriegn Application Priority Data
Foreign Country	Foreign Patent Number	Foreign Patent Date
Japan	JP2016-157732	Aug 10, 2016

International Family Members for US Patent 11,306,106

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Argentina	109315
Australia	2017310774
Australia	2023202350
Brazil	112019001911