US Patent 10,716,868: FACBC PET Imaging Claims, Exclusivity, and Patent Landscape

US Patent 10,716,868 protects a highly specific clinical imaging protocol for administering [18F]-FACBC, marketed as Axumin, and acquiring PET images for recurrent or metastatic prostate cancer. The patent does not claim the FACBC molecule, its radiochemical synthesis, the Axumin product generally, or every use of FACBC PET. Its principal value is in protocol control: fasting, exercise restriction, arm placement, injection timing, early image acquisition, scan geometry, repeat imaging, and diagnostic comparison.

The claims are method-of-use claims. Infringement generally requires performance of each limitation of an asserted claim, either directly by a healthcare provider or through potential liability theories involving entities that direct or control the protocol.

What does US Patent 10,716,868 cover?

The patent covers administration of [18F]-FACBC followed by early PET imaging of at least the pelvic region. The core protocol includes:

Limitation	Claims containing the limitation
[18F]-FACBC injected into an arm	1, 15, 17
No food or water for at least four hours	1, 6-20, subject to claim structure
No significant exercise before imaging	1, 15, 19, 20
Arm in an overhead position during imaging	1-14, 17-18
PET imaging begins approximately 3-5 minutes after injection	1-16
Four-minute imaging start	2
Injection over approximately 1-2 minutes	3-4
Right-arm injection	6, 16
250-500 MBq dose	6
Repeat imaging after one month to one year	8, 18
Comparison of image locations or intensities	7-9, 17-20
Diagnosis or monitoring of recurrent or metastatic cancer	9, 15, 17-20
PET/CT or PET/MRI	10-11, 15-16
At least four bed positions	12-14
Feet-to-head scanning direction	12
Proximal-thigh starting position	13
Completion within 30 minutes	14

The broadest practical protection is concentrated in claim 1. Claims 15 and 17 provide alternative independent claim structures directed respectively to combined PET/CT or PET/MRI diagnosis and repeat-scan comparison.

How strong is the patent estate for Axumin and [18F]-FACBC?

The patent estate should be divided into four categories:

Compound and tracer patents. These concern FACBC itself, radiolabeled amino-acid analogues, or their chemical preparation.
Manufacturing patents. These cover production of [18F]-FACBC, precursor chemistry, automated synthesis, purification, and quality-control processes.
Clinical-use patents. These cover imaging prostate cancer, recurrent disease, metastatic disease, or other tumors.
Protocol patents. US 10,716,868 falls principally into this category.

US 10,716,868 is narrower than a compound patent but can be commercially relevant because it targets the operational protocol used in routine Axumin PET imaging. A competing provider may avoid literal infringement by changing one required parameter, such as the fasting period, arm position, acquisition timing, scan direction, or repeat-imaging interval. That avoidance strategy may not eliminate risk if another claim remains satisfied or if the changed parameter is considered an insubstantial variation under the doctrine of equivalents.

The patent is strongest against standardized imaging protocols that reproduce the claimed conditions. It is weaker against individualized clinical practice, protocols that omit one limitation, and facilities using different acquisition timing or patient positioning.

What are the independent claims in US 10,716,868?

Claim 1: Early pelvic PET imaging after controlled administration

Claim 1 requires all of the following:

injection of [18F]-FACBC into an arm;
no food or water for at least four hours;
no significant exercise from the day before imaging through image acquisition;
the arm positioned overhead during PET imaging;
image acquisition beginning approximately three to five minutes after injection.

This claim does not require a prostate-cancer diagnosis, a particular dose, a right-arm injection, a PET/CT system, a particular number of bed positions, or a repeat scan. Its breadth comes from the absence of those additional restrictions.

A facility that injects Axumin into the arm, imposes the stated fasting and exercise restrictions, raises the arm overhead, and begins pelvic PET acquisition four minutes later could potentially meet claim 1 even if it uses a dose outside 250-500 MBq or does not perform PET/CT.

Claim 15: Combined PET/CT or PET/MRI diagnosis

Claim 15 requires:

injection into an arm while the arm is adjacent to the torso;
subsequent overhead positioning;
acquisition on a combined PET/MRI or PET/CT scanner;
imaging beginning approximately three to five minutes after injection;
fasting for at least four hours;
no significant exercise from the day before the scan;
diagnosis of recurrent prostate tumors or metastatic tumors.

This claim is narrower than claim 1 because it requires a combined scanner and an express diagnostic step. It also creates a protocol sequence: the arm is adjacent to the torso during injection and later remains overhead during scanning.

Claim 16 adds right-arm injection while the patient is lying horizontally and raising the arm to the overhead position less than approximately five seconds after injection. That timing limitation materially narrows the claim.

Claim 17: Repeat imaging and comparative diagnosis

Claim 17 requires:

a first [18F]-FACBC injection and PET scan;
the arm overhead during the first scan;
a second performance of the injection and imaging steps;
comparison of tracer locations or intensities;
diagnosis of recurrent prostate or metastatic tumor based on the comparison.

Unlike claim 1, claim 17 does not independently require the no-exercise limitation. Claims 19 and 20 add exercise restrictions for the first and second scans.

Claim 18 narrows the repeat scan to an interval of one month to one year. The claim therefore targets surveillance and longitudinal monitoring rather than a single diagnostic examination.

Which claims protect Axumin formulation or manufacturing?

None of the listed claims directly protects the Axumin formulation, the vial, the precursor, or the radiochemical manufacturing process.

The claims require use of [18F]-FACBC but do not specify:

a particular excipient;
a stabilizer;
a pH range;
a container;
a precursor compound;
a synthesis route;
a purification step;
a quality specification;
a kit;
a commercial formulation.

A manufacturer could therefore face separate patent issues for producing [18F]-FACBC even if its clinical customers avoid the protocol claims. Conversely, a facility could potentially practice a patented imaging method using a product made by a different manufacturer.

What method-of-use protection does the patent provide?

The patent protects specific use conditions rather than the therapeutic or diagnostic concept of using FACBC for prostate cancer generally.

The principal protected use is:

Administer [18F]-FACBC under defined patient-preparation and positioning conditions, acquire early pelvic PET images, and use tracer localization or intensity to detect, diagnose, or monitor recurrent or metastatic cancer.

The method-of-use protection is strongest where the protocol is written into:

institutional imaging manuals;
radiology order sets;
technologist checklists;
patient preparation instructions;
electronic scheduling systems;
scanner acquisition protocols;
clinical trial protocols;
radiopharmacy and imaging-center contracts.

Those documents can provide evidence of intent, direction, or control if infringement litigation arises.

When does US Patent 10,716,868 expire?

The patent was granted on July 14, 2020, according to the US patent record. Its effective expiration depends on the earliest nonprovisional priority date, patent-term adjustment, terminal disclaimers, and any patent-term extension.

For a US patent filed from a modern application, the ordinary term is generally 20 years from the earliest effective nonprovisional filing date, subject to statutory adjustments under 35 U.S.C. § 154. The grant date alone does not establish the expiration date.

The patent should therefore be analyzed using the USPTO patent-term data rather than a simple 20-year calculation. A term extending into the mid-2030s is commercially plausible for a continuation or national-stage application with a 2014-2015 priority chain, but the exact expiration date requires the official continuity and term-adjustment records.

What is the FDA and Orange Book status of Axumin?

Axumin is the commercial name for fluciclovine F 18 injection, the FDA-approved [18F]-FACBC radiopharmaceutical.

FDA item	Status
Product	Axumin
Active ingredient	Fluciclovine F 18
Dosage form	Injectable radiopharmaceutical
NDA	208054
Sponsor at approval	Blue Earth Diagnostics Ltd.
FDA approval	May 2016
Principal use	PET imaging in men with suspected recurrent prostate cancer based on elevated PSA after prior treatment

The FDA-approved use is narrower than every possible use in US 10,716,868. The patent claims include metastatic and recurrent cancer language and detailed acquisition procedures. Regulatory approval does not by itself establish infringement, and a patent claim can cover a protocol that is narrower, broader, or operationally different from the approved labeling.

Orange Book relevance depends on whether the patent was listed against NDA 208054 and whether the listing remained active for the relevant period. A method patent must meet FDA listing rules and must claim the approved drug, a method of using the approved drug, or an approved use. A live Orange Book listing would increase the regulatory significance of a generic or competing NDA challenge, but it would not automatically prevent non-ANDA use by imaging providers.

Are there Paragraph IV challenges to US 10,716,868?

A Paragraph IV challenge would normally arise from an abbreviated new drug application asserting that a listed patent is invalid, unenforceable, or not infringed.

For Axumin, the more likely regulatory issue is not a traditional high-volume generic-drug substitution model. [18F]-FACBC is a short-lived radiopharmaceutical, and manufacturing, distribution, site-of-use logistics, and PET-center access can be as important as formulation substitution.

A Paragraph IV risk analysis should distinguish:

Risk category	Relevance to US 10,716,868
ANDA certification	Relevant only if the patent is listed and the product is pursued through an ANDA pathway
505(b)(2) application	Potentially more relevant for a different formulation, manufacturing process, or labeling approach
Compounded or site-produced FACBC	May create patent risk without following a conventional generic pathway
Imaging-center use	Direct method-of-use exposure independent of an ANDA
Biosimilar pathway	Not applicable because Axumin is a small-molecule radiopharmaceutical, not a biologic

No biosimilar challenge applies to Axumin. The relevant competitors are generic or alternative radiopharmaceutical developers, compounding facilities, radiopharmacies, and PET imaging providers.

What patent litigation affects US Patent 10,716,868?

The supplied claim set does not establish a particular infringement case, settlement, or validity decision involving US 10,716,868. The patent should not be treated as adjudicated valid, infringed, or enforceable solely because it issued.

Potential litigation issues include:

lack of written description for the full combination of protocol limitations;
enablement of all claimed patient, timing, positioning, and scan combinations;
anticipation by clinical imaging protocols;
obviousness based on FACBC PET imaging publications and standard PET practice;
indefiniteness of terms such as “significant exercise,” “about,” “overhead position,” and “at least a pelvic region”;
patent-eligibility challenges to diagnostic comparison steps;
divided infringement involving radiopharmacies, imaging centers, technologists, and physicians;
extraterritorial performance of parts of the protocol.

The diagnostic elements in claims 9, 15, and 17 may attract scrutiny under 35 U.S.C. § 101 because they use tracer localization or intensity to reach a cancer diagnosis. The claims also contain substantial physical and operational steps, including injection and image acquisition. Eligibility analysis would depend on the claim as a whole and the evidentiary record.

What generic-entry risks exist for Axumin?

The practical entry risk is divided into three scenarios.

Protocol-compliant entry

A competing [18F]-FACBC product used under the same fasting, arm-positioning, early-scan, and repeat-imaging protocol presents the highest method-claim risk. The risk increases if the sponsor supplies instructions that reproduce the patented workflow.

Protocol-avoiding entry

A competitor may reduce risk by changing one or more variables:

imaging begins outside the three-to-five-minute window;
the patient’s arm is not overhead;
fasting does not include water;
exercise restrictions differ;
imaging begins outside 30 minutes;
the scan does not use the claimed bed-position sequence;
repeat scans are not performed within one month to one year.

Avoidance must be assessed claim by claim. Removing the dose limitation in claim 6, for example, does not avoid claim 1.

Alternative-tracer entry

Other prostate-cancer PET tracers, including PSMA-targeted agents, may avoid FACBC-specific claims entirely. This is a competitive threat to Axumin independent of patent expiry. PSMA PET products can compete for recurrent-prostate-cancer imaging without using [18F]-FACBC.

How does US 10,716,868 compare with broader compound patents?

Patent type	What it protects	Competitive effect
Compound patent	FACBC or related chemical entity	Broadest chemical exclusion, if valid and unexpired
Manufacturing patent	Radiolabeling, precursors, purification, synthesis	Can restrict supply even when clinical-use patents are avoided
Label or indication patent	Use in prostate-cancer imaging	Can affect regulatory labeling and generic entry
US 10,716,868	Detailed administration and PET acquisition protocol	Strongest against standardized protocol replication

US 10,716,868 is therefore a secondary but potentially enforceable layer of protection. Its commercial value depends on whether imaging centers use the claimed protocol as a standard operating procedure and whether alternative scan timing or patient positioning affects image quality.

Key Takeaways

US 10,716,868 is a protocol patent, not a compound or formulation patent.
Claim 1 is the central broad claim and requires fasting, exercise restriction, arm injection, overhead arm positioning, and PET acquisition approximately three to five minutes after injection.
Claims 15 and 17 create separate enforcement pathways for combined PET/CT or PET/MRI diagnosis and repeat-scan comparison.
The patent does not cover every use of Axumin or every FACBC PET scan.
No biosimilar pathway applies because Axumin is a small-molecule radiopharmaceutical.
Generic or alternative-product risk depends on Orange Book listing, regulatory pathway, manufacturing rights, and whether the proposed labeling directs the patented protocol.
The strongest design-around options involve acquisition timing, arm positioning, patient preparation, and repeat-imaging parameters.
Exact patent expiration requires USPTO continuity, patent-term-adjustment, and terminal-disclaimer data rather than the grant date alone.
The main competitive threat is not limited to generic FACBC. PSMA PET agents can compete without practicing FACBC-specific claims.

FAQs

Does US Patent 10,716,868 claim Axumin itself?

No. It claims methods of administering and imaging with [18F]-FACBC. It does not claim the molecule, vial formulation, precursor, or manufacturing process.

Can a PET center infringe without selling Axumin?

Potentially. A PET center may directly practice a method claim by administering [18F]-FACBC and acquiring images under the claimed conditions, even if another company supplies the radiopharmaceutical.

Does changing the injection dose avoid the patent?

Not necessarily. Dose is expressly required only in claim 6. A facility using a different dose could still satisfy claim 1 or another independent claim.

Are PET/CT and PET/MRI both covered?

Yes, but only under the claims that expressly require combined PET/CT or PET/MRI imaging, principally claims 10, 11, 15, and 16.

Does the patent cover PSMA PET imaging?

No. The claims are directed to [18F]-FACBC. PSMA-targeted radiopharmaceuticals fall outside the literal scope of these claims because they use a different tracer.

References

U.S. Patent No. 10,716,868. (2020). Methods of administering anti-1-amino-3-[18F]fluorocyclobutane-1-carboxylic acid and acquiring PET images. United States Patent and Trademark Office.
U.S. Food and Drug Administration. (2016). Axumin (fluciclovine F 18 injection) prescribing information. FDA.
U.S. Food and Drug Administration. (n.d.). Approved drug products with therapeutic equivalence evaluations. FDA.
United States Code. (2024). 35 U.S.C. §§ 101, 102, 103, 112, 154, and 271.
United States Patent and Trademark Office. (n.d.). Patent term adjustment and patent term extension records. USPTO.

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	10,716,868	⤷ 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: 10,716,868

Which drugs does patent 10,716,868 protect, and when does it expire?

Summary for Patent: 10,716,868