# US Patent 11,980,674: FACBC PET Imaging Claims, Exclusivity, Litigation Risk, and Patent Landscape

US Patent 11,980,674 protects a specific clinical-use protocol for [18F]-FACBC, also known as fluciclovine F 18 and marketed as Axumin. The patent does not claim fluciclovine as a chemical compound, a radiopharmaceutical composition, or a manufacturing process. Its independent claims require a combination of administration, patient-preparation, bladder-management, and pelvic PET-imaging steps.

The commercially important limitations are:

Intravenous bolus administration of [18F]-FACBC.
At least four hours without food or drink, except sips of water for medication.
Bladder voiding 30 to 60 minutes before administration.
No bladder voiding until PET imaging is complete.
Imaging of at least the pelvic region.
In claim 1, a scan starting three to five minutes after injection is an additional dependent limitation, not a requirement of the independent claim.
Claim 18 uses “treating” language but recites administration and diagnostic imaging rather than a therapeutic intervention.

What does US Patent 11,980,674 cover?

The patent covers a method of conducting an [18F]-FACBC PET examination under a defined patient-preparation and imaging protocol.

Independent claim 1

Claim 1 requires every element below:

Element	Required limitation
Radiotracer	Anti-1-amino-3-[18F]fluorocyclobutane-1-carboxylic acid
Route	Intravenous bolus injection
Patient	Human subject
Fasting	No food or drink, including water, for at least four hours, except medication sips
Bladder preparation	Voiding approximately 30 to 60 minutes before administration
Post-voiding restriction	No voiding until PET imaging is complete
Imaging	PET scan of at least the pelvic region

A provider that uses [18F]-FACBC but does not follow the fasting or bladder restrictions would not literally practice every limitation of claim 1. Conversely, a protocol that follows those requirements but uses a different PET tracer would fall outside the literal scope of claim 1.

The claim is therefore narrow in its protocol requirements but potentially broad in the types of clinical sites, scanners, prostate-cancer patients, and commercially sourced [18F]-FACBC that can be used.

Claim 18

Claim 18 is a second independent method claim. It recites a method of “treating” a human subject, but the operative steps are:

Intravenous bolus administration of [18F]-FACBC.
Four-hour food and drink restriction.
Bladder voiding 30 to 60 minutes before administration.
PET imaging of at least the pelvic region.
Refraining from voiding until image acquisition is complete.

The claim does not require a therapeutic drug, surgery, radiation treatment, or other intervention. Its practical scope is directed to a diagnostic imaging episode. The “treating” preamble may generate claim-construction and validity disputes because the body of the claim describes imaging rather than treatment. Its legal effect would depend on whether a court treats the preamble as limiting and how the claim is construed in an infringement or validity proceeding.

What do the dependent claims add?

The dependent claims define an operational imaging protocol that resembles a standardized Axumin PET workflow.

Claims	Added limitation
2	Injection into the arm
3	Avoidance of significant exercise from the prior day through imaging
4	PET acquisition begins three to five minutes after injection ends
5	Suspected prostate-cancer recurrence
6	Dose of 250 to 500 MBq
7	Dose of 290 to 450 MBq
8	Dose of 370 MBq plus or minus 20%
9	Dose of 370 MBq
10	Dilution before injection
11	Dilution up to 10 mL
12	Supine positioning with arms above the head
13	Scan from proximal thigh to base of skull
14	Image includes proximal thigh
15	Analysis for a sub-centimeter lesion suspicious for recurrence with uptake above blood pool
16	Identification of the lesion as suspicious for recurrence
17	Injection into the right arm

Claims 6 through 9 create overlapping dose ranges. Claim 9 is the narrowest dose claim. Claim 8 covers 296 to 444 MBq if “370 plus or minus 20%” is treated mathematically.

Claims 13 and 14 are important for protocol comparison. A whole-body or skull-base-to-thigh scan may satisfy claim 13, while a scan limited to the pelvis may satisfy claim 1 but not necessarily claims 13 or 14.

How strong is the patent estate for US Patent 11,980,674?

The patent has moderate enforcement value for standardized clinical protocols and weaker value against every use of [18F]-FACBC.

Strengths

The claims recite concrete clinical steps rather than an abstract indication alone.
Fasting, bladder timing, injection route, scan timing, dose, and positioning can be documented in patient records and imaging protocols.
The claims are tailored to prostate-cancer recurrence imaging, the principal US use of Axumin.
A competing provider could practice the claim without making or selling the tracer.
Dependent claims provide narrower fallback positions if broader claims face validity or construction challenges.

Weaknesses

The patent does not block manufacture or sale of [18F]-FACBC by itself.
The claims require a particular patient-preparation protocol that may not be used in every clinical setting.
Several limitations are operationally variable, including “approximately 30 minutes to 60 minutes,” “significant exercise,” “at least a pelvic region,” and “greater than blood pool.”
The claimed protocol may overlap with clinical practice described in prior Axumin labeling, clinical studies, or earlier patent families.
The claim set does not independently require a confirmed prostate-cancer recurrence or a positive PET result.
Claim 18 may face scrutiny because it labels the method as treatment while reciting diagnostic imaging steps.

The strongest practical claims are likely claims 1, 4, 5, 6, 8, 12, and 15. Claims 9, 11, 17, and 18 are narrower or more susceptible to factual distinctions.

What FDA status and Orange Book issues affect the patent?

Axumin is an FDA-approved positron emission tomography radiopharmaceutical containing fluciclovine F 18. FDA approved Axumin under NDA 208054 for PET imaging in men with suspected prostate-cancer recurrence based on elevated prostate-specific antigen levels following prior treatment.[2]

FDA labeling identifies a recommended adult dose of 370 MBq and describes PET acquisition beginning approximately three to five minutes after administration. The label also instructs patients to void immediately before administration and to remain hydrated.[2] The patent claims impose a more specific bladder sequence and a four-hour restriction on food and drink.

The Orange Book analysis must distinguish between:

FDA approval of Axumin;
patents listed against the NDA;
patent claims covering the product itself;
patent claims covering a method of use; and
regulatory exclusivity periods.

A method-of-use patent can affect an ANDA applicant through a Paragraph IV certification even when the patent does not claim the active ingredient or finished drug product. The relevant question is whether the listed patent has a use code corresponding to the proposed generic label and whether the applicant seeks approval for that use.

US Patent 11,980,674 should not be treated as a composition patent merely because it identifies [18F]-FACBC. Its claims are method claims. A generic applicant seeking a label that omits the patented fasting, bladder, or pelvic-imaging protocol may argue that the patent is not applicable to the proposed labeling. A patent holder may respond that the proposed label or expected standard practice encourages performance of the claimed method.

When does US Patent 11,980,674 lose exclusivity?

The issue date of US Patent 11,980,674 is May 7, 2024. The ordinary US patent term is generally 20 years from the earliest effective nonprovisional US filing date, subject to patent-term adjustment, terminal disclaimers, and any applicable patent-term extension.[3]

The expiration date cannot be calculated from the patent number or issue date alone. For a continuation patent, the effective term is ordinarily tied to the earliest claimed priority application, not the continuation’s filing date. The controlling record is the patent’s front page, continuity data, terminal-disclaimer information, and USPTO Patent Center transaction history.[1]

The patent’s commercial life may also be shorter than its statutory term because:

Axumin sales depend on the approved indication and reimbursement;
a competing fluciclovine product could use a different label;
providers may avoid one or more protocol limitations;
a court could invalidate or narrow the claims; or
the claims could be removed from the Orange Book or become irrelevant to a competing label.

FDA regulatory exclusivity is separate from patent exclusivity. Axumin’s initial new-drug exclusivity period does not extend to 2024 and does not independently prevent generic or 505(b)(2) competition today.[2]

Are Paragraph IV challenges likely?

A Paragraph IV challenge is legally possible if the patent is listed in the Orange Book and an ANDA applicant seeks approval for a use covered by the listed claims.

The principal challenge grounds would be:

Ground	Potential argument
Anticipation	A prior publication or clinical protocol disclosed the complete fasting, bladder, injection, and pelvic-imaging combination
Obviousness	The claimed steps were routine optimization of known Axumin PET procedures
Indefiniteness	Terms such as “approximately,” “significant exercise,” and “suspicious” lack sufficient boundary
Written description	The full combination, particularly the no-voiding and fasting requirements, was not adequately supported
Enablement	The specification does not enable the full scope of clinical implementations
Non-infringement	The proposed label omits one or more required preparation or imaging steps
Divided infringement	No single entity performs or controls all patient and provider steps

The patent’s narrower claims may survive if the broader claims are challenged, especially where the record supports the 370 MBq dose, three-to-five-minute scan timing, and prostate-recurrence use.

What generic launch risks exist?

The most plausible launch scenarios are:

Carve-out launch

An ANDA or 505(b)(2) applicant could seek approval for [18F]-FACBC imaging while excluding the patented protocol from its label. The risk is that routine clinical use still follows the patented instructions, creating potential induced-infringement allegations.

Full-label launch after litigation

A full-label applicant could file a Paragraph IV certification and litigate validity, enforceability, and infringement. The commercial value of the patent would depend on whether the patented protocol is central to the proposed label.

Non-infringing protocol

A competitor could distinguish its use by changing one or more elements, such as:

allowing normal hydration;
using a different pre-scan voiding instruction;
beginning imaging outside the three-to-five-minute period;
using a different dose;
limiting imaging to a different anatomical field; or
using another amino-acid PET tracer.

A protocol variation must be assessed claim by claim. Changing the dose does not avoid claim 1 if the claim-1 limitations remain satisfied.

Is there biosimilar risk for [18F]-FACBC?

There is no conventional biosimilar pathway for Axumin. Fluciclovine F 18 is a small-molecule radiopharmaceutical, not a biologic. Competitive products would more likely proceed through an ANDA, 505(b)(2), or other applicable drug pathway rather than a biosimilar application.

The more relevant barriers are:

radiopharmaceutical manufacturing approval;
short radioactive half-life and regional distribution;
qualified cyclotron and synthesis capacity;
sterile production and quality-control systems;
PET-center supply logistics;
reimbursement and payer coverage;
FDA labeling strategy; and
method-of-use patents such as US 11,980,674.

What manufacturing and geographic barriers remain?

US Patent 11,980,674 does not claim the synthesis or manufacture of [18F]-FACBC. It therefore does not directly prevent a qualified manufacturer from producing the tracer using a non-infringing process.

Manufacturing barriers may arise from other patent families covering:

precursor compounds;
radiochemical labeling processes;
automated synthesis cassettes;
purification methods;
formulation and stability;
sterile filling;
quality-control assays; and
distribution systems.

Geographic rights also require separate review. A US patent does not block use or manufacture in Europe, Canada, Japan, or other jurisdictions. The corresponding PCT and national-phase applications may have different claim scope, prosecution outcomes, expiration dates, and litigation histories.

Which companies are challenging or competing with Axumin?

The principal competitive set is not limited to generic fluciclovine. Prostate-cancer recurrence imaging also includes:

Product or technology	Active imaging agent	Competitive relevance
Axumin	Fluciclovine F 18	Product protected by the claimed protocol
Pluvicto-related PSMA imaging ecosystem	Gallium-68 or fluorine-18 PSMA agents	Competes for prostate-cancer imaging and treatment pathways
PYLARIFY	Piflufolastat F 18	FDA-approved PSMA PET agent for prostate cancer
Illuccix	Gallium-68 gozetotide	PSMA PET imaging competitor
Locametz	Gallium-68 gozetotide	PSMA PET imaging competitor

PSMA PET agents have reduced the strategic importance of fluciclovine in many prostate-cancer imaging workflows. Axumin remains relevant where clinicians use amino-acid imaging, where PSMA access is limited, or where payer and institutional protocols favor fluciclovine.

What litigation affects US Patent 11,980,674?

The claims supplied do not establish a litigation history for US Patent 11,980,674. Patent-level litigation must be checked in PACER, the USPTO Patent Center, and the Orange Book listing history. FDA approval does not establish that a patent has been litigated, listed, or successfully enforced.

The principal litigation questions are:

Whether the patent is listed against NDA 208054.
Whether an ANDA applicant has filed a Paragraph IV certification.
Whether any 30-month stay was triggered.
Whether a settlement agreement restricts launch timing.
Whether the patent has a terminal disclaimer.
Whether any post-grant, inter partes review, or reexamination proceeding exists.

No settlement date or generic launch date should be inferred solely from the patent’s issuance.

How does this patent compare with a composition or formulation patent?

US Patent 11,980,674 is materially narrower than a composition patent.

Patent type	Commercial effect
Composition patent	Can block making, using, selling, or importing the claimed molecule
Formulation patent	Can block a specified dosage form, concentration, excipient system, or stability profile
Manufacturing patent	Can block a defined synthesis or radiolabeling process
Method-of-use patent	Can block performance of the claimed clinical use
US 11,980,674	Targets a defined [18F]-FACBC PET workflow

A competitor that manufactures the same tracer but markets it for a non-covered protocol may avoid direct literal infringement. A competitor that promotes the same fasting, bladder, dose, and scan workflow faces a higher risk.

Key Takeaways

US Patent 11,980,674 is a clinical method-of-use patent for [18F]-FACBC PET imaging.
It does not claim fluciclovine as a molecule, finished formulation, or manufacturing process.
The core claim requires intravenous bolus injection, four-hour fasting, pre-scan voiding, post-voiding restriction, and pelvic PET imaging.
Dependent claims add dose, timing, positioning, exercise, anatomical coverage, and lesion-analysis limitations.
Claim 18 uses “treating” language but recites diagnostic imaging steps.
The patent may be relevant to Paragraph IV analysis only if properly listed and tied to the proposed generic use.
Conventional biosimilar risk does not apply because fluciclovine F 18 is a small-molecule radiopharmaceutical.
The principal competitive pressure comes from PSMA PET products, including piflufolastat F 18 and gallium-68 gozetotide.
Patent expiration must be determined from the earliest effective priority date, terminal-disclaimer status, and patent-term adjustment, not from the 2024 issue date alone.
The patent’s enforcement value is strongest against standardized Axumin imaging protocols and weaker against modified clinical workflows.

FAQs About US Patent 11,980,674

Does US Patent 11,980,674 prevent the sale of fluciclovine F 18?

No. The supplied claims are method claims and do not directly claim the compound, finished drug product, or manufacturing process.

Does a PET center infringe if it administers Axumin without requiring fasting?

Literal infringement of claim 1 would be less likely if the four-hour food-and-drink restriction is absent, because that limitation is expressly required.

Is the 370 MBq dose required by the main claim?

No. Claim 1 does not recite a dose. The 370 MBq dose appears in dependent claims 8 and 9.

Does imaging only the pelvis avoid the patent?

Not necessarily. Claim 1 expressly requires imaging of at least a pelvic region. A pelvis-only scan may satisfy that limitation while avoiding claims requiring proximal-thigh-to-skull-base coverage.

Can a PSMA PET product infringe this patent?

A PSMA PET product would generally not satisfy the [18F]-FACBC limitation. The patent is directed to fluciclovine F 18, not PSMA-targeted radiotracers.

References

United States Patent and Trademark Office. (2024). U.S. Patent No. 11,980,674.
U.S. Food and Drug Administration. (2023). Axumin (fluciclovine F 18) injection prescribing information.
United States Code. (2024). 35 U.S.C. §§ 154 and 156: Patent term and patent term extension.
U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations. Orange Book.

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate
Blue Earth	AXUMIN	fluciclovine f-18	SOLUTION;INTRAVENOUS	208054-001	May 27, 2016		RX	Yes	Yes	11,980,674	⤷ Start Trial				POSITRON EMISSION TOMOGRAPHY DIAGNOSTIC AGENT IN ADULTS WITH SUSPECTED PROSTATE CANCER RECURRENCE BASED ON ELEVATED BLOOD PROSTATE SPECIFIC ANTIGEN LEVELS FOLLOWING PRIOR TREATMENT	⤷ 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

Details for Patent: 11,980,674

Which drugs does patent 11,980,674 protect, and when does it expire?

Summary for Patent: 11,980,674