U.S. Patent 10,179,140: Drospirenone-Only Contraception Claims, Patent Scope and Competitive Landscape
U.S. Patent No. 10,179,140 protects selected methods of using crystalline drospirenone without estrogen for contraception in patients with a BMI of at least 25 kg/m². Its broadest claim combines patient selection, a drospirenone dose range, repeated treatment cycles, absence of estrogen, and a bleeding-related clinical result. Dependent claims add bleeding thresholds, weight loss, heart-rate reduction, particle size, dose, pharmacokinetic, dosage-form, and dissolution limitations.
The patent is most relevant to 4 mg drospirenone oral contraceptive products, including the Slynd product class. The strongest practical exposure is the combination of a 4 mg crystalline drospirenone tablet, an estrogen-free formulation, and use in overweight or obese patients under a multi-cycle regimen. The narrower pharmacokinetic and dissolution claims create additional formulation-specific barriers but are more difficult to prove in ordinary commercial use.
What drug and contraceptive technology does U.S. Patent 10,179,140 cover?
The patent covers estrogen-free contraception using crystalline drospirenone. The central technology is a progestin-only oral contraceptive administered over an initial cycle and subsequent consecutive cycles.
The independent claim requires all of the following:
| Claim element |
Requirement |
| Patient population |
Patient with BMI of at least 25 kg/m² |
| Therapeutic purpose |
Providing contraception |
| Active ingredient |
Crystalline drospirenone |
| Dose |
2.5 mg to 5.5 mg |
| Excipients |
One or more pharmaceutically acceptable excipients |
| Estrogen |
Pharmaceutical composition does not contain estrogen |
| Regimen |
Daily administration for at least portions of the initial and subsequent cycles |
| Clinical result |
Limited bleeding events in at least one subsequent cycle |
A product or method that omits any one of these limitations may avoid literal infringement of claim 1, subject to the doctrine of equivalents and the construction adopted by a court.
The claim is directed to a method of treatment rather than merely to a composition. That distinction matters. A generic tablet with the same active ingredient and dose may not, by itself, infringe the method claim. Liability would ordinarily depend on the product label, prescribing instructions, commercial promotion, or evidence that the claimed patient population and treatment regimen are intended or induced.
How broad is claim 1 of U.S. Patent 10,179,140?
Claim 1 is broad in patient population and treatment-cycle duration, but narrow in its combination of required limitations.
Patient population
The BMI threshold of 25 kg/m² includes overweight and obese patients. It is not limited to patients with BMI of 30 kg/m² or higher. A label or instruction directed to patients with BMI of at least 25 kg/m² would fall within the express population limitation.
The claim does not appear to require:
- A particular age;
- A particular baseline bleeding pattern;
- A particular ethnic group;
- A specific contraceptive failure rate;
- A particular number of treatment cycles;
- A particular BMI upper limit.
The use of BMI creates an important infringement issue. BMI must be measured or reasonably inferred for an individual patient. A generic label that does not mention BMI may present a stronger defense against induced infringement than a label that expressly discusses use in overweight or obese women.
Dose
The claimed range is 2.5 mg to 5.5 mg of crystalline drospirenone. A 4 mg product is directly within the range. Claims 32 and 33 narrow this to 3.0 mg to 4.5 mg and specifically 4 mg.
A product containing 2 mg or 6 mg of drospirenone would fall outside the literal dose range of claim 1. Dose equivalence, tablet splitting, multiple-tablet administration, and bioequivalence could still raise claim-construction or equivalents issues.
Estrogen exclusion
The composition must not contain an estrogen. This limitation separates the patent from combined oral contraceptives containing ethinyl estradiol, estetrol, or another estrogen.
A drospirenone product containing only progestin is the principal commercial target. A combined drospirenone-estrogen product would not satisfy the express “does not contain an estrogen” limitation.
Bleeding outcome
Claim 1 requires a “limited number of days of bleeding events” in at least one subsequent treatment cycle. This is a result-based limitation. It may create proof problems because the claim does not, standing alone, provide a single numerical threshold.
Claims 2 through 6 add thresholds ranging from no more than about 13% to no more than about 5% per treatment cycle. The percentage appears to refer to the proportion of days with bleeding events during a treatment cycle, although the claims do not define the denominator in the supplied text.
What dependent claims add to the patent scope?
The dependent claims divide into four principal groups: clinical outcomes, treatment timing, physical properties, and product performance.
Clinical-outcome claims
Claims 2-11 address reductions in bleeding events:
- No more than about 13% of days per cycle;
- No more than about 11%;
- No more than about 10%;
- No more than about 7%;
- No more than about 5%;
- Reductions of about 44% to 85% compared with the initial cycle;
- Reductions of about 50% to 75%;
- Reductions of at least 20%, 40%, or 60%.
Claims 7-11 focus on the second through ninth cycles. They therefore target early-cycle stabilization and may be supported by clinical bleeding diaries or trial datasets.
Claims 12-16 add weight-loss results. The claimed weight loss is approximately 1 kg to 10 kg, with narrower ranges of 1 kg to 4 kg. The resulting BMI reduction is 1% to 20%, or 1% to 5%.
Claims 17-21 add resting-heart-rate reductions, including:
- At least 5 beats per minute;
- At least 15 beats per minute;
- A percentage reduction of approximately 2% to 20%;
- A narrower reduction of approximately 5% to 7%.
These claims are narrower and present substantial causation and measurement issues. A patient’s weight and resting heart rate can change because of diet, exercise, illness, medication, adherence, or measurement conditions. The claims do not appear to require that drospirenone be the exclusive cause of the observed change, but infringement analysis would depend on the specification and claim construction.
Treatment-cycle claims
Claim 22 defines the subsequent cycles as the first through thirtieth cycles following the initial cycle. Claims 12 and 17 also use the first through thirtieth subsequent cycles for weight and heart-rate measurements.
This limitation can affect generic labeling. A label that instructs continuous daily administration for several months may provide evidence for the cycle-related limitations even if it does not describe the clinical outcomes.
Particle-size claims
Claims 23-31 address non-micronized crystalline drospirenone in particle form. The relevant parameters include:
| Property |
Claimed range |
| Specific surface area |
About 2,000 to 8,500 cm²/g |
| Particle diameter |
About 200 μm or less |
| d50 |
About 10 μm to 60 μm |
| d90 |
Less than about 100 μm |
| Narrow d90 |
About 20 μm to 40 μm |
| Narrow d50 |
About 10 μm to 30 μm |
| d10 |
More than about 3 μm |
| Narrow d10 |
About 3 μm to 9 μm |
These claims are potentially important because particle size can affect dissolution, absorption, and dose uniformity. They are also technically fact-intensive. Infringement testing may require representative batch sampling, validated particle-size methodology, and agreement on measurement technique.
“Non-micronized” does not necessarily mean coarse. Claims 25-31 define relatively specific particle characteristics despite the non-micronized designation. A manufacturer using a different particle engineering process may seek to remain outside these ranges while maintaining acceptable bioavailability.
Dose-form and performance claims
Claims 34-39 focus on a single daily oral tablet and a defined pharmacokinetic or dissolution profile.
The claimed pharmacokinetic parameters include:
- Tmax of about 2.2 to 6 hours;
- Mean Cmax below 30 ng/mL under fasting conditions;
- Mean Cmax of 15 to 30 ng/mL;
- AUC0-tlast of at least 300 ng·h/mL.
Claim 39 requires a specific USP XXIII Paddle Method dissolution profile:
- No more than 50% dissolved within 30 minutes; and
- At least 50% dissolved within 3 to 4 hours.
These claims can reach a product even where the label does not disclose particle size. However, they require testing under specified or reconstructed conditions. Differences in apparatus, paddle speed, medium, volume, sampling time, and analytical method can materially affect the result.
What patents protect drospirenone-only contraception besides U.S. Patent 10,179,140?
The relevant patent estate is broader than the supplied claims. It is likely to include several categories:
| Patent category |
Typical protected subject matter |
Commercial relevance |
| Method-of-use patents |
Estrogen-free contraception and bleeding control |
Direct label and use risk |
| Formulation patents |
4 mg drospirenone tablets, excipients, release profile |
Product composition risk |
| Particle patents |
Crystalline or non-micronized drospirenone particle properties |
Manufacturing and formulation risk |
| Pharmacokinetic patents |
Exposure, Cmax, Tmax, and AUC profiles |
Product-performance risk |
| Dissolution patents |
Delayed or controlled dissolution behavior |
Tablet-development risk |
| Manufacturing patents |
Crystallization, milling, blending, compression |
Process substitution issues |
| Regulatory exclusivity |
New-drug, clinical, pediatric, or other FDA exclusivity |
Entry timing independent of patent term |
Patent-family analysis must distinguish continuation, divisional, reissue, terminal-disclaimer, and foreign-family rights. A patent number alone does not establish the full estate, its current ownership, or its enforceability.
What is the Orange Book status of the drospirenone product?
The relevant FDA product is an estrogen-free oral contraceptive containing 4 mg drospirenone. FDA labeling identifies the product as a progestin-only oral contraceptive and describes a 24 active-tablet and 4 inert-tablet regimen for the marketed product class (FDA, 2024).
Orange Book analysis should examine:
- Whether U.S. Patent 10,179,140 is listed against the relevant reference listed drug;
- Whether the listing covers the active ingredient, formulation, or method of use;
- The listed patent expiration date;
- Any pediatric exclusivity attached to a listed patent;
- Whether later patents were submitted through patent-listing supplements;
- Whether the generic applicant must make a Paragraph IV certification.
The supplied claim text does not establish the current Orange Book listing status or a definitive expiration date. Those facts must be verified against the FDA Orange Book and the patent’s official prosecution and term-adjustment records rather than inferred from the claims alone (FDA, 2024; USPTO, 2024).
When does U.S. Patent 10,179,140 lose exclusivity?
The patent’s effective expiration date cannot be reliably calculated from the claims provided. A precise date requires the patent’s earliest effective nonprovisional priority, patent-term adjustment, patent-term extension, terminal disclaimer, and any applicable pediatric exclusivity.
For a post-June 8, 1995 U.S. utility patent, the general term is 20 years from the earliest effective nonprovisional U.S. filing date, subject to adjustment and extension under 35 U.S.C. §§ 154 and 156. The issue date is not normally the starting point for the 20-year term (35 U.S.C. § 154).
The relevant commercial timeline is therefore:
| Event |
Legal significance |
| Patent grant |
Creates enforceable issued claims |
| FDA approval |
Starts product commercialization |
| Orange Book listing |
Supports statutory notice and potential stay |
| Paragraph IV notice |
Can trigger patent litigation |
| Patent expiration |
Ends ordinary patent exclusion |
| Pediatric exclusivity, if any |
May extend listed protection by six months |
| Regulatory exclusivity expiration |
May independently affect generic approval |
What Paragraph IV challenges and litigation risks exist?
A generic applicant could challenge the patent through a Paragraph IV certification if the patent is listed for the reference product. Likely attack positions include:
Written description and enablement
The patent claims a broad BMI population, multiple clinical outcomes, particle parameters, pharmacokinetic values, and dissolution behavior. A challenger could argue that the specification does not adequately support the full breadth of every claimed range or every combination of limitations.
Indefiniteness
Potential targets include:
- “Limited number of days of bleeding events”;
- “About” 5%, 7%, 10%, 11%, and 13%;
- “Subsequent consecutive treatment cycles”;
- The meaning of “initial treatment cycle”;
- The measurement basis for weight and resting heart rate.
Obviousness
A challenger could combine prior art relating to:
- Drospirenone-only contraception;
- 4 mg drospirenone dosing;
- Continuous or cyclic oral contraceptive regimens;
- Known bleeding outcomes;
- Particle-size optimization;
- Standard tablet dissolution and pharmacokinetic testing.
The strongest non-obviousness defense would likely rely on an unexpected clinical result, such as a particular bleeding profile in overweight or obese patients, combined with a defined drospirenone formulation.
Infringement proof
Method claims create special proof issues. The patentee may need evidence that the accused product’s labeling or conduct directs administration to patients with BMI of at least 25 kg/m² and over consecutive cycles. Formulation and dissolution claims are easier to test physically but may be avoided through a different manufacturing process or release profile.
No current Paragraph IV notice, ANDA litigation outcome, or settlement term is established by the claim text supplied here. Such facts must be confirmed through FDA records and federal court filings.
Does biosimilar risk apply to U.S. Patent 10,179,140?
No. Drospirenone is a chemically synthesized small molecule, not a biologic. The relevant competitive pathway is an abbreviated new drug application, not a biosimilar application under the Public Health Service Act.
A generic applicant would generally evaluate:
- Orange Book patent listings;
- Paragraph I, II, III, or IV certifications;
- Bioequivalence;
- Label carve-outs for patented methods of use;
- Formulation differences;
- Potential induced-infringement exposure.
The absence of biosimilar risk does not eliminate patent risk. It shifts the analysis to Hatch-Waxman litigation, formulation design, and labeling strategy.
How strong is the patent estate for a 4 mg drospirenone tablet?
The estate is strongest where the commercial product aligns with several claim layers at once:
- 4 mg crystalline drospirenone;
- No estrogen;
- Daily oral tablet dosing;
- Consecutive treatment cycles;
- Patient BMI of at least 25 kg/m²;
- Claimed bleeding outcome;
- Claimed particle-size and dissolution parameters.
Risk is lower for a product that uses a different drospirenone dose, includes estrogen, employs materially different particle characteristics, produces a different dissolution profile, or uses a label that omits the claimed patient population and clinical instructions.
The estate is more vulnerable where protection depends on post-treatment outcomes rather than readily observable product characteristics. Clinical-result claims can be commercially valuable but are harder to enforce without patient-level evidence and a clear causal framework.
What generic launch scenarios are most plausible?
At-risk launch before patent expiry
A generic may launch after FDA approval but before final patent resolution. This creates possible damages, injunction, and market-withdrawal exposure if the patent survives and is found infringed.
Paragraph III launch
A generic may accept the patent and defer commercial launch until the relevant patent and exclusivity periods expire.
Skinny-label launch
A generic may remove a patented method of use from its label if FDA regulations permit the carve-out and the remaining label does not encourage the patented use. This strategy is less effective if the commercial product’s ordinary instructions inherently practice the claimed regimen.
Formulation-around strategy
A manufacturer may use different particle-size distributions, excipients, dissolution characteristics, or manufacturing processes. That approach must account for other patents in the family and any formulation patents not represented in the supplied claims.
Key Takeaways
- U.S. Patent 10,179,140 is a method-of-use patent centered on estrogen-free crystalline drospirenone contraception.
- Claim 1 requires a BMI of at least 25 kg/m², a 2.5 mg to 5.5 mg drospirenone dose, repeated daily administration, and a bleeding-related result.
- The 4 mg dose is expressly covered by claim 33 and is the most commercially important embodiment.
- Claims 23-31 add particle-size and specific-surface-area limitations.
- Claims 34-39 add single-tablet, pharmacokinetic, and dissolution limitations.
- The patent does not create biosimilar risk because drospirenone is a small molecule.
- Generic risk will depend heavily on Orange Book listing, label language, formulation testing, and any Paragraph IV litigation.
- A definitive patent expiration date, current Orange Book status, litigation history, and settlement position cannot be derived from the supplied claims alone.
Frequently Asked Questions
Does a 4 mg drospirenone tablet fall within U.S. Patent 10,179,140?
Yes. Claims 1, 32, and 33 expressly cover crystalline drospirenone in a range that includes 4 mg, provided the other claim limitations are met.
Does the patent cover drospirenone combined with ethinyl estradiol?
No. The independent claim requires a pharmaceutical composition that does not contain an estrogen.
Can a generic avoid the patent by using micronized drospirenone?
Potentially. Claims 23-31 expressly recite non-micronized drospirenone or particle characteristics. Avoidance would depend on the full patent family, product testing, and whether other claims cover the alternative material.
Does the BMI threshold include overweight patients?
Yes. A BMI of 25 kg/m² or more includes patients classified as overweight and patients with obesity.
Is a different dissolution profile enough to avoid infringement?
It may avoid claim 39 if the product does not meet the specified dissolution parameters. It would not, by itself, avoid claim 1 or unrelated method, formulation, or manufacturing claims in the patent family.
References
Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations. U.S. Department of Health and Human Services.
Food and Drug Administration. (2024). Slynd prescribing information. U.S. Department of Health and Human Services.
United States Code. (2024). 35 U.S.C. §§ 154, 156.
United States Patent and Trademark Office. (2024). Manual of patent examining procedure. U.S. Department of Commerce.
United States Patent No. 10,179,140. (2019). Methods of contraception using drospirenone. U.S. Patent and Trademark Office.
