US Patent 7,320,970: Scope, Claim Construction, Expiration, and Patent Landscape for Sequential Estrogen-Norgestimate Hormone Replacement Therapy

US Patent 7,320,970 protects a six-day hormone-replacement sequence: three consecutive days of estrogen-only therapy followed by three consecutive days of estrogen plus a progestogen having activity equivalent to approximately 90 micrograms of norgestimate per day. The patent also covers kits containing the products in that sequence.

The patent is a regimen and packaging patent, not a broad composition-of-matter patent. Its commercial relevance centered on sequential estrogen/norgestimate hormone-replacement products such as Prefest. The claims do not require one named estrogen, one dosage strength, or one administration route. They do require the specific three-day/three-day sequence and the norgestimate-equivalent progestogenic component in the second phase.

The patent term has ended or is no longer an active commercial barrier based on the public patent record. It does not create a current biosimilar issue because the covered products are conventional small-molecule hormone products.

What does US Patent 7,320,970 cover?

The patent covers two related categories:

A method of treating a female requiring hormone replacement therapy.
A pharmaceutical kit containing sequential dosage forms for that treatment.

The essential regimen is:

Phase	Duration	Required active ingredients
Phase 1	Three consecutive daily dosage forms	A substance exhibiting estrogenic activity
Phase 2	Three consecutive daily dosage forms	An estrogenic substance plus progestogenic activity equivalent to about 90 µg norgestimate per day

The cycle can be repeated. The claims do not expressly limit the number of six-day cycles, the specific estrogen, or the total treatment duration.

The patent issued on January 22, 2008, as US Patent 7,320,970. The issued claims are directed to hormone-replacement treatment and sequential kits rather than to the underlying chemical structure of estradiol, norgestimate, or another active pharmaceutical ingredient. (United States Patent and Trademark Office [USPTO], 2008; Google Patents, n.d.)

How should claim 1 of US 7,320,970 be construed?

Claim 1 has four material limitations.

Female patient requiring hormone replacement therapy

The method must be performed on a female who is in need of hormone replacement therapy. This language narrows the claim relative to a general contraceptive, menopausal-symptom, or gynecologic-treatment claim.

A product used solely for contraception would not automatically satisfy this limitation. The relevant treatment purpose, prescribing context, labeling, and physician instructions would matter in a method-of-use analysis.

Three consecutive estrogen-only dosage forms

The first phase requires three consecutive daily dosage forms, or an equivalent thereof, containing a substance with estrogenic activity.

The claim does not specify:

Estradiol rather than another estrogen;
A particular estradiol dose;
Tablet strength;
Oral administration;
A branded product;
A particular excipient or formulation;
A particular estrogen salt or ester.

The phrase "or an equivalent thereof" expands the claim beyond a literal three-tablet presentation. A manufacturer could not necessarily avoid the claim by using a patch, capsule, liquid, or other dosage form if the product performs the same three-day estrogen-only phase.

Three consecutive estrogen-plus-progestogen dosage forms

The second phase requires three consecutive daily dosage forms containing both:

A substance exhibiting estrogenic activity; and
A substance exhibiting progestogenic activity equivalent to approximately 90 µg of norgestimate per day.

The second phase therefore requires continued estrogen exposure. A regimen that provides progestogen alone during days four through six would not literally satisfy claim 1.

Norgestimate-equivalent progestogenic activity

The claim does not require the chemical compound norgestimate itself. It requires progestogenic activity equivalent to about 90 µg norgestimate per day.

That language potentially covers:

Norgestimate at approximately 90 µg per day;
Another progestogen shown to provide equivalent activity;
A formulation delivering a pharmacologically equivalent progestogenic effect.

The principal litigation issue would be how "equivalent" is measured. Potential measures include pharmacodynamic activity, clinical dose equivalence, receptor activity, or the dose used in a reference product. The claim does not identify a single assay or conversion method, leaving room for claim-construction disputes.

What do claims 2 through 5 add?

Claims 2 through 5 narrow the method claim but do not materially change the core regimen.

Claim	Added limitation	Commercial effect
2	Placebo, iron supplement, vitamin supplement, or combination	Covers calendar-pack or supplemental-product presentations
3	Oral, parenteral, transdermal, transmucosal, intramuscular, or intravaginal administration	Expressly confirms multiple delivery routes
4	Oral dosage form	Narrows claim 3 to oral products
5	Oral tablet	Narrowest dosage-form claim in the method series

Claim 2 is drafted awkwardly because it refers to the method further comprising administration of a placebo or supplement. It may be relevant to products with inactive tablets, iron tablets, or vitamin tablets in a calendar package.

Claims 3 through 5 are important for product-design analysis. A competitor using an oral tablet would fall within the narrower claims if the core six-day regimen is met. A transdermal or vaginal product would be evaluated primarily under claim 3, assuming the active-ingredient and sequence limitations are satisfied.

What does claim 6 protect?

Claim 6 is the principal kit claim. It covers a pharmaceutical kit containing:

Three consecutive estrogen-only dosage forms; and
Three consecutive dosage forms containing estrogen plus norgestimate-equivalent progestogenic activity;

with the two groups positioned sequentially in the kit.

This claim is directed to the commercial presentation of the regimen, not only to patient use. It can potentially reach:

Calendar blister packs;
Wallet packs;
Unit-dose cartons;
Bundled dosage forms;
Other packaging that positions the first and second phases sequentially.

The kit claim does not expressly require the kit to contain instructions for hormone replacement therapy. It does require the sequence to be embodied in the positioning of the dosage forms.

How do claims 7 through 10 affect kit coverage?

Claims 7 through 10 parallel claims 2 through 5.

Claim 7 adds placebo, iron, vitamin, or combinations. Claim 8 identifies administration routes. Claim 9 limits the dosage forms to oral administration. Claim 10 limits the oral dosage forms to tablets.

The kit claims are commercially significant because a manufacturer could face infringement exposure from the package even if the product labeling or actual prescribing behavior creates a more difficult method-of-use case.

What formulations are protected by US Patent 7,320,970?

The claims can cover a wide range of formulations if they preserve the required sequence.

Potentially covered formulations

Oral estradiol tablets for days 1 through 3;
Oral estradiol/norgestimate tablets for days 4 through 6;
Transdermal estrogen products followed by combined estrogen/progestogen products;
Intravaginal estrogen products followed by combined therapy;
Kits containing separate estrogen-only and combination phases;
Packs containing placebo, iron, or vitamin tablets in addition to the active phases.

Formulations outside the literal core

A product may fall outside the literal claim if it:

Uses fewer or more than three consecutive days in either phase;
Provides estrogen and progestogen during all six days;
Provides estrogen alone for six days;
Uses a progestogen without equivalent activity to approximately 90 µg norgestimate;
Does not provide estrogen in the second phase;
Does not involve hormone replacement therapy.

The doctrine of equivalents could still be relevant where a product makes only an insubstantial change to the sequence or dosing structure. The three-day limitations are likely to receive meaningful weight because they define the regimen's central architecture.

Is US Patent 7,320,970 a composition patent or a method patent?

It is principally a method-of-use and kit patent.

Patent category	Covered by US 7,320,970?
Estradiol chemical structure	No
Norgestimate chemical structure	No
Broad estrogen composition	No
Broad progestogen composition	No
Sequential hormone-replacement method	Yes
Sequential pharmaceutical kit	Yes
Oral tablet embodiment	Yes, under dependent claims
Manufacturing process	Not based on the listed claims
Packaging arrangement	Yes, under the kit claims

This distinction limits the patent's ability to block unrelated estrogen or progestogen products. A competitor would need to practice the claimed sequence, not merely sell an estrogen-containing product.

What is the Orange Book status of the patent?

Orange Book relevance depends on the specific approved drug application and on whether the patent was submitted and listed against that application. A patent number alone does not establish current Orange Book listing status.

For an approved product containing estradiol and norgestimate, the relevant regulatory questions are:

Whether the NDA holder submitted US 7,320,970 for listing;
Whether FDA accepted the listing;
Whether the patent was removed after expiration;
Whether any ANDA applicant certified under Paragraph IV;
Whether the NDA holder initiated infringement litigation within the statutory period.

FDA Orange Book records, rather than the patent document, control the regulatory listing analysis. (FDA, 2024a)

The patent's expiration materially reduces its current Orange Book significance. An expired patent cannot support a new 30-month stay based on a current Paragraph IV notice.

When did US Patent 7,320,970 lose exclusivity?

The patent's enforceable term is determined by the earliest effective nonprovisional filing date, applicable patent-term-adjustment period, and any terminal disclaimer or patent-term extension. The issue date does not determine expiration.

The public patent record identifies US 7,320,970 as an issued patent from 2008, but its commercial exclusivity period has ended. The patent should therefore be treated as an expired or otherwise nonblocking right for current generic-launch analysis, subject to confirmation in the USPTO maintenance and patent-term records. (USPTO, n.d.)

There is no biologic exclusivity period associated with this patent. The covered active ingredients are small molecules, and the relevant approval pathway would be an NDA/ANDA framework rather than a BLA/351(k) pathway.

Were there Paragraph IV challenges or patent litigation?

The principal regulatory exposure would have arisen from an ANDA applicant seeking approval for a generic sequential estradiol/norgestimate product.

A Paragraph IV challenge would have targeted one or more of the following issues:

Anticipation by earlier sequential hormone-replacement regimens;
Obviousness of a three-day estrogen-only followed by three-day combination regimen;
Lack of written description or enablement for broad estrogen and delivery-route language;
Indefiniteness of "equivalent" progestogenic activity;
Noninfringement based on a different sequence or dose;
Invalidity based on prior public use or earlier marketed products.

No current litigation risk can be inferred from the patent number alone. The absence of an active Orange Book listing or a current infringement case would be consistent with the patent's expired status and the commercial discontinuation of the relevant product line.

What commercial product was most closely associated with the patent?

The claim structure is closely aligned with a Prefest-type product containing estradiol and norgestimate. Prefest used sequential estrogen-only and estrogen-plus-norgestimate dosing in a calendar-style regimen. The patent's 90-µg norgestimate reference is a strong product-specific indicator.

The commercial importance of the patent depended on three factors:

Factor	Relevance
Product availability	A discontinued or low-volume product reduces practical enforcement value
Orange Book listing	Listing could have delayed ANDA approval during the patent term
Product substitution	Generic or therapeutic alternatives could reduce revenue exposure

Because the patent does not cover estradiol or norgestimate as chemical entities, its value was limited to the particular regimen and kit architecture.

How strong is the patent estate?

The estate is moderately narrow but potentially effective during its active term.

Strengths

Claims identify a precise and commercially recognizable regimen.
The claims cover both treatment conduct and the packaged product.
The claims are not limited to one named estrogen.
The route claims reach oral, transdermal, parenteral, transmucosal, intramuscular, and intravaginal delivery.
The kit claims could create a direct product-based infringement theory.

Weaknesses

The three-day/three-day sequence creates a clear design-around path.
The claim does not cover estrogen or norgestimate compositions broadly.
"Equivalent" progestogenic activity may create uncertainty in litigation.
Prior sequential hormone-regimen products could support anticipation or obviousness arguments.
The patent has no current blocking value if expired.
The underlying therapeutic area has multiple noninfringing alternatives.

The most defensible commercial claim was likely claim 6 against a sequential calendar pack that reproduced the same six-day architecture. The broadest treatment claim, claim 1, carried greater validity and claim-construction exposure because of its generalized estrogen and progestogen language.

What generic launch scenarios existed?

During the patent term, a generic sponsor had several possible design strategies:

Strategy	Patent risk
Copy the exact three-day/three-day regimen	High
Use estrogen alone for a different duration	Lower
Use combined estrogen/progestogen throughout treatment	Lower
Change the second-phase progestogen or dose materially	Potentially lower
Use a continuous regimen	Lower
Market separate products without sequential kit positioning	Lower kit-claim risk, but method risk remains
Challenge validity under Paragraph IV	Regulatory litigation risk
Wait for patent expiration	Lowest patent risk

A product with the same active ingredients but a continuous regimen would not automatically infringe. Conversely, changing the package while preserving the exact administered sequence could avoid some kit claims but would not necessarily avoid claim 1.

What manufacturing and intellectual-property barriers remain?

The patent does not materially block manufacture of:

Estradiol;
Norgestimate;
Generic hormone tablets;
Transdermal estrogen systems;
General estrogen/progestogen combinations.

The primary historical barrier was the need to reproduce the protected sequence and package. Regulatory barriers could include:

ANDA bioequivalence;
Demonstration of pharmaceutical equivalence;
Labeling limitations;
Patent certifications;
Product-specific Orange Book requirements;
Manufacturing controls for low-dose hormone products.

Manufacturing-process patents, formulation patents, trademark rights, and regulatory exclusivities must be analyzed separately. They are not established by the claims provided for US 7,320,970.

How does this patent compare with competing hormone-replacement patent strategies?

Strategy	Typical protection	Relative scope
Sequential regimen patent	Timing and order of active ingredients	Narrow but commercially targeted
Continuous-combination patent	Daily estrogen plus progestogen	Broader around continuous use
Composition patent	Specific active ingredient or salt	Potentially broad, but chemically limited
Formulation patent	Release profile, stability, delivery system	Product-specific
Method-of-use patent	Treatment of a defined condition or population	Depends on labeling and prescribing
Kit patent	Packaged sequence and product arrangement	Strong against copied calendar packs

US 7,320,970 is strongest against a direct copy of a sequential calendar-pack product. It is weaker against continuous regimens, different cycle lengths, different progestogens, and products sold without the claimed sequential arrangement.

Key Takeaways

US Patent 7,320,970 covers a three-day estrogen-only phase followed by a three-day estrogen-plus-progestogen phase.
The progestogenic activity must be equivalent to about 90 µg of norgestimate per day.
The patent covers both treatment methods and sequential pharmaceutical kits.
The claims are not limited to estradiol, tablets, oral dosing, or one branded product.
Claims 3 and 8 expressly extend beyond oral products to several administration routes.
The patent does not cover estradiol, norgestimate, or broad hormone compositions as such.
The claim language is vulnerable to design-around strategies using different cycle lengths, continuous therapy, or materially different progestogen dosing.
The patent's commercial relevance was associated with Prefest-type estradiol/norgestimate therapy.
The patent should be treated as expired or otherwise nonblocking for current launch analysis.
Current Orange Book and litigation conclusions must be tied to the specific NDA and FDA listing history, not the patent document alone.

FAQs

Does US Patent 7,320,970 cover every estradiol and progestin product?

No. It covers products and treatment methods using the specified sequential three-day estrogen-only and three-day estrogen-plus-progestogen regimen.

Can a generic avoid the patent by using a different estrogen?

Potentially. Claim 1 is not limited to estradiol, but a different estrogen would still infringe if the product met the same sequence and progestogenic-equivalence limitations.

Does a six-day package infringe if the tablets are not placed in sequential order?

The kit claims require sequential positioning. A package lacking that arrangement may avoid the literal kit claims, although the treatment method claims could still apply to the actual administration sequence.

Is a biosimilar application relevant to this patent?

No. Estradiol and norgestimate are small-molecule active ingredients. The relevant pathway is generally an NDA/ANDA framework, not a biosimilar BLA/351(k) pathway.

Can a continuous estrogen-plus-progestogen product infringe US 7,320,970?

A continuous product would generally lack the required initial three consecutive days of estrogen-only dosage forms. It would therefore present a materially lower literal infringement risk.

References

Food and Drug Administration. (2024a). Approved drug products with therapeutic equivalence evaluations. U.S. Department of Health and Human Services. https://www.fda.gov/drugs/drug-approvals-and-databases/orange-book
Google Patents. (n.d.). US7320970B2: Hormone replacement therapy. https://patents.google.com/patent/US7320970B2
U.S. Patent and Trademark Office. (2008). U.S. Patent No. 7,320,970, Hormone replacement therapy. https://patents.google.com/patent/US7320970B2
U.S. Patent and Trademark Office. (n.d.). Patent term adjustment and patent term information. https://www.uspto.gov/patents/laws/patent-term-adjustment-pta-calculation】【。

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Argentina	029159	⤷ Start Trial
Australia	3412300	⤷ Start Trial
Brazil	0010968	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 7,320,970

Summary for Patent: 7,320,970