US Patent 9,579,359: Degarelix Dosing Claims, Expiration, Orange Book Status, and Patent Landscape
US Patent 9,579,359 protects a specific degarelix treatment regimen for prostate cancer. Its core coverage is a loading dose of 160 to 320 mg, delivered as two subcutaneous injections, followed by 60 to 160 mg every 20 to 36 days, with testosterone suppression below 0.5 ng/mL. The commercially relevant Firmagon regimen, 240 mg initially followed by 80 mg monthly, falls within the independent claim.
The patent is assigned to the Ferring group and is directed primarily to method-of-treatment and dosing implementation, rather than to the basic discovery of degarelix. The principal commercial risk is an ANDA applicant seeking approval for the labeled regimen before patent expiration.
What does US Patent 9,579,359 protect?
The patent protects a complete clinical protocol, not merely the use of degarelix in prostate cancer.
| Claim element |
Scope of US 9,579,359 |
| Disease |
Prostate cancer |
| Active ingredient |
Degarelix |
| Initial dose |
160-320 mg |
| Initial administration |
Two subcutaneous injections |
| Maintenance dose |
60-160 mg |
| Dosing interval |
Every 20-36 days |
| Pharmacodynamic result |
Testosterone below 0.5 ng/mL |
| Clinical objective |
Treatment with reduced likelihood of testosterone spike or GnRH-agonist side effects |
| Key dependent limitations |
Monthly dosing, PSA reductions, BMI below 30 kg/m², concentration and injection-volume parameters |
The claim is narrower than a general claim covering degarelix for androgen-deprivation therapy. An accused regimen must satisfy every limitation of claim 1 or an applicable dependent claim.
What is the scope of independent claim 1?
Claim 1 contains five material limitations:
- Treatment of prostate cancer.
- Use of degarelix.
- An initial dose between 160 and 320 mg.
- Delivery of that initial dose through two subcutaneous injections.
- A maintenance dose between 60 and 160 mg every 20 to 36 days.
- Testosterone suppression below 0.5 ng/mL.
- A reduced likelihood of testosterone spike or other GnRH-agonist side effects.
The claim uses open-ended dose ranges. A 240 mg loading dose and an 80 mg maintenance dose are inside the claimed ranges. Monthly administration is also within the 20-to-36-day interval and is expressly recited in claim 2.
The functional language creates a potential proof issue. “Reduced likelihood” and “testosterone suppression below 0.5 ng/mL” require a factual showing based on the treatment regimen and clinical evidence. The claim does not require a particular percentage reduction in testosterone, but it does require suppression below the stated threshold.
How do the patent claims map onto the Firmagon label?
Firmagon is approved for the treatment of advanced prostate cancer. The FDA-approved regimen begins with 240 mg administered as two 120 mg subcutaneous injections, followed by 80 mg as a single subcutaneous injection every 28 days.[1]
| Firmagon label parameter |
Firmagon regimen |
Claim 1 or dependent claim |
| Loading dose |
240 mg |
Within 160-320 mg |
| Loading injections |
Two |
Expressly required |
| Maintenance dose |
80 mg |
Within 60-160 mg |
| Interval |
Every 28 days |
Within 20-36 days |
| Maintenance administration |
Single injection |
Claim 11 |
| Initial concentration |
40 mg/mL after reconstitution |
Claims 9 and 10 |
| Maintenance concentration |
20 mg/mL after reconstitution |
Claims 12 and 13 |
| Testosterone endpoint |
Below castrate threshold |
Claim 1 |
| PSA outcomes |
Covered by specified dependent claims |
Claims 4-7 |
The overlap with the approved product is substantial. Claims 2, 10, 11 and 13 track important elements of the labeled regimen and presentation.
What formulations are protected by US 9,579,359?
The patent does not broadly claim every degarelix formulation. Claims 9 through 13 attach concentration limitations to the treatment method.
Initial-dose concentration
Claim 9 covers an initial degarelix concentration of 5 to 40 mg/mL. Claim 10 narrows the range to 40 mg/mL.
A 240 mg loading dose at 40 mg/mL corresponds to two 3 mL injections, consistent with the Firmagon presentation.
Maintenance-dose concentration
Claim 12 covers a maintenance concentration of 5 to 40 mg/mL. Claim 13 narrows the concentration to 20 mg/mL.
An 80 mg maintenance dose at 20 mg/mL corresponds to a 4 mL injection. Claim 11 separately requires the maintenance dose to be given as a single injection.
These claims are method claims with formulation and administration limitations. They do not necessarily prevent a competitor from developing a different concentration or injection volume, provided the alternative regimen avoids the complete combination of limitations in the asserted claim.
What clinical outcomes are covered by the dependent claims?
Claims 4 through 7 add PSA-response limitations:
| Claim |
Required outcome |
| 4 |
At least 30% PSA reduction by day 14 |
| 5 |
At least 60% PSA reduction by day 28 |
| 6 |
At least 80% likelihood of maintaining PSA below about 5 ng/mL |
| 7 |
For locally advanced prostate cancer, at least 40% PSA reduction by day 14 |
These claims are narrower and may be more difficult to enforce against a generic applicant unless the proposed labeling instructs use in a way that necessarily produces or targets the claimed outcomes. A label that merely describes degarelix treatment may not expressly induce performance of every PSA-response limitation.
Claim 8 limits the subject to a body mass index below 30 kg/m². This limitation further narrows the claim and creates a patient-selection restriction.
When does US Patent 9,579,359 expire?
Public patent records identify an expected expiration date in 2027, commonly reported as August 20, 2027, subject to the controlling USPTO term calculation and any applicable patent-term adjustment.[2]
The patent issued on February 28, 2017. Its remaining term is therefore materially shorter than the term of a newly filed patent. The expiration date is separate from FDA regulatory exclusivity.
| Exclusivity category |
Relevance to degarelix |
| Patent exclusivity |
Controlled by the surviving US patent term, including US 9,579,359 and any other unexpired patents |
| New chemical entity exclusivity |
Expired for Firmagon |
| Orphan-drug exclusivity |
Not the principal barrier for the approved Firmagon indication |
| 30-month ANDA stay |
Available if the NDA holder or patent owner timely sues after a Paragraph IV notice |
| Pediatric exclusivity |
No material conclusion follows from the patent claims alone |
A patent expiration date does not guarantee immediate generic launch. FDA review, first-filer status, other patents, litigation settlements, manufacturing readiness and injunction risk can affect entry timing.
What is the Orange Book status of US Patent 9,579,359?
The relevant regulatory question is whether the patent is listed for the Firmagon NDA and whether its listing remains active for the relevant product and use codes. Orange Book listing determines whether an ANDA applicant must make a Paragraph I, II, III or IV certification.[3]
For a listed method-of-use or drug-product patent:
- A Paragraph III certification states that the applicant will wait until patent expiration.
- A Paragraph IV certification alleges that the patent is invalid, unenforceable or not infringed.
- Notice of a Paragraph IV certification can trigger patent litigation.
- A timely infringement action can impose a 30-month stay on final FDA approval, subject to statutory exceptions and court orders.
US 9,579,359 is particularly relevant to an ANDA directed to the approved 240 mg loading and 80 mg monthly maintenance regimen because those parameters fall directly within the patent claims. A product with a materially different dosing interval, injection architecture or concentration could reduce literal infringement exposure, but it would need to remain therapeutically and regulatorily acceptable.
What Paragraph IV challenges are possible?
A generic applicant could challenge the patent through several theories.
Non-infringement
The applicant could design around one or more required elements, such as:
- A maintenance interval outside 20 to 36 days.
- A loading dose outside 160 to 320 mg.
- A loading administration method other than two subcutaneous injections.
- A maintenance concentration outside the claimed ranges.
- A regimen that does not produce testosterone below 0.5 ng/mL.
- Labeling that does not direct use for the claimed PSA or BMI subgroups.
The strongest design-around argument would usually target a required structural dosing limitation rather than the clinical side-effect language.
Invalidity
Potential validity challenges could include:
- Anticipation based on earlier degarelix clinical protocols.
- Obviousness based on prior degarelix dosing studies and the known Firmagon development program.
- Lack of written description for the full dose, interval and response ranges.
- Lack of enablement for the complete scope of the functional treatment language.
- Indefiniteness involving “reduced likelihood,” “other GnRH agonist side effect” or “about.”
The patent’s clinical-response limitations may create both a validity issue and an infringement-proof issue. A court would evaluate the claim language, specification, prosecution history and cited prior art rather than the commercial label alone.
Patent eligibility
Patent eligibility is a less direct attack. The claims are framed as concrete treatment methods involving a specified drug, dosage, route and interval. That structure is materially different from a bare claim to an observed biological correlation.
How strong is the patent estate for Firmagon?
The commercial strength of US 9,579,359 is moderate to strong against a conventional generic that copies the approved regimen, but weaker against a genuine regimen redesign.
| Risk factor |
Assessment |
| Alignment with approved label |
High |
| Claim breadth |
Moderate |
| Dependence on clinical outcomes |
Increases proof complexity |
| Concentration coverage |
Strong for labeled presentations |
| Design-around potential |
Moderate |
| Generic litigation exposure |
High for a label-matching ANDA |
| Biosimilar exposure |
Not applicable in the conventional sense |
| Manufacturing barrier |
Meaningful but separate from this patent |
| Remaining patent term |
Limited to the late 2020s, based on public term reporting |
The patent does not cover the entire degarelix molecule, every pharmaceutical composition or every use of androgen-deprivation therapy. Its value is concentrated in the approved administration protocol.
Is biosimilar competition relevant to degarelix?
Degarelix is regulated as a drug under an NDA rather than as a conventional FDA biologic licensed under a BLA. The primary abbreviated pathway is therefore an ANDA or, depending on product differences, a 505(b)(2) application rather than a biosimilar application under the Public Health Service Act.[4]
A follow-on applicant would need to address:
- Pharmaceutical equivalence.
- Bioequivalence or appropriate clinical bridging.
- Peptide characterization and impurity controls.
- Reconstitution performance.
- Injection-site tolerability.
- Device and presentation differences.
- Listed patents and use codes.
Degarelix is a peptide antagonist, so manufacturing complexity remains relevant even after patent expiry. The product requires reliable control of aggregation, purity, reconstitution and subcutaneous delivery. Those barriers can delay competition but do not extend the patent term.
What litigation and settlement issues affect generic entry?
A Paragraph IV challenge directed to the approved Firmagon regimen could produce litigation under the Hatch-Waxman Act. The principal issues would likely involve infringement of claim 1 and the enforceability or validity of the dosing claims.
A settlement could provide:
- An agreed generic entry date before patent expiration.
- A launch license subject to manufacturing or regulatory conditions.
- A covenant not to sue for a redesigned regimen.
- Restrictions tied to particular indications or labeling.
- A licensed launch after patent expiration.
No settlement terms should be inferred from the patent claims themselves. Patent ownership, Orange Book listing, FDA correspondence and court dockets must be analyzed separately from the issued claims.
Ferring’s commercial position also depends on any later-issued or separate patents directed to formulation, manufacturing, delivery or additional treatment methods. US 9,579,359 should not be treated as the complete Firmagon patent estate.
How does US 9,579,359 compare with a basic degarelix patent?
| Issue |
US 9,579,359 |
Basic compound or composition patent |
| Subject matter |
Clinical dosing method |
Molecule, composition or formulation |
| Infringement trigger |
Performing the claimed regimen |
Making, using or selling covered product |
| Relevance to Firmagon label |
Direct |
May be broader or narrower |
| Design-around route |
Change dose, interval, concentration or administration |
Change molecule or formulation |
| Clinical proof |
Often important |
Usually less dependent on patient outcomes |
| Generic exposure |
High for label-matching regimen |
Potentially broader |
| Expiration impact |
Blocks claimed regimen until term ends |
May block product more generally |
What generic launch scenarios exist?
Scenario 1: Label-matching ANDA
A generic applicant copies 240 mg in two injections followed by 80 mg every 28 days. This is the highest infringement-risk scenario because the regimen maps closely to claims 1, 2, 10, 11 and 13.
Scenario 2: Same active ingredient, modified regimen
The applicant uses a different dose, interval or injection configuration. This may reduce literal infringement risk but creates regulatory and clinical-development burdens.
Scenario 3: 505(b)(2) product
A sponsor proposes a different concentration, delivery system or dosing schedule while relying partly on Firmagon data. Patent certifications and possible litigation remain relevant.
Scenario 4: Post-expiration entry
A generic or follow-on sponsor waits until the relevant patent term ends. This avoids the principal patent dispute but does not eliminate manufacturing, FDA review or product-quality barriers.
Key Takeaways
- US 9,579,359 is a regimen patent covering degarelix treatment for prostate cancer.
- The Firmagon regimen of 240 mg in two subcutaneous injections followed by 80 mg every 28 days falls within the central claim structure.
- Claims 9 through 13 cover concentration and injection-format parameters corresponding to the commercial presentation.
- PSA-response and BMI claims are narrower and may be more difficult to prove in an infringement case.
- Public records report expiration in 2027, commonly August 20, 2027, subject to the controlling USPTO term calculation.
- A label-matching ANDA would face meaningful Paragraph IV and 30-month-stay exposure if the patent is listed and timely asserted.
- Degarelix competition is expected to proceed through generic or 505(b)(2) pathways, not a conventional biosimilar pathway.
- The patent protects the dosing protocol, not the entire degarelix molecule or every future formulation.
- Manufacturing and peptide-quality controls may remain commercial barriers after patent expiry.
FAQs
Does US Patent 9,579,359 cover the Firmagon 240 mg loading dose?
Yes. The 240 mg loading dose is within the claimed 160-to-320 mg range, and the labeled two-injection administration matches claim 1.
Does monthly degarelix dosing infringe the patent?
Monthly dosing can fall within the patent because “monthly” is expressly recited in claim 2 and a 28-day interval is within the 20-to-36-day range in claim 1.
Can a generic avoid the patent by changing the injection concentration?
Potentially, but only if the complete alternative regimen falls outside the asserted claims and does not infringe under the doctrine of equivalents. A concentration change also requires FDA and clinical justification.
Is a degarelix follow-on product a biosimilar?
Ordinarily no. Degarelix is marketed under an NDA, so a follow-on sponsor would generally consider an ANDA or 505(b)(2) route rather than a biosimilar application.
Do the PSA claims independently block every generic degarelix product?
No. Claims 4 through 7 are dependent claims with additional PSA or disease-subgroup limitations. The central commercial barrier is claim 1 and the claims covering the labeled dose, interval, concentration and injection format.
References
- U.S. Food and Drug Administration. (2024). Firmagon (degarelix acetate) prescribing information. FDA.
- United States Patent and Trademark Office. (2017). U.S. Patent No. 9,579,359, Methods of treating prostate cancer. USPTO Patent Center.
- U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations, Orange Book. FDA.
- U.S. Food and Drug Administration. (2024). Abbreviated new drug application and 505(b)(2) application pathways. FDA.
