US Patent 4,544,554 Scope and Claim Map for Low-Dose 21-Day Estrogen-Progestogen Contraception Regimens (21/7 Cyclic Dosing)

Executive summary. United States Patent 4,544,554 claims a cyclic oral combined contraception regimen built around 21 successive days of daily administration in three consecutive phases using 17α-ethinylestradiol (EE) plus a progestogen (notably norethindrone or other listed progestogens), followed by 6–8 days (claim 9 and claim 10 specify 7 days) without estrogen/progestogen. The patent’s independent claim scope is defined by (i) fixed EE daily activity range (0.02–0.05 mg EE equivalents) across all phases, (ii) phase-dependent progestogen escalation (for norethindrone: 0.065–0.75 mg first phase; 0.250–1.0 mg second phase; 0.35–2.0 mg third phase), and (iii) phase durations with specific numeric windows (first 5–8 days, next 7–11 days, next 3–7 days), then an estrogen/progestogen-free interval. Dependent claims narrow to oral admixture, seven-day phases, and specific estrogen/progestogen identities and concrete dose sets (including EE 0.035 mg with norethindrone 0.50/0.75/1.0 mg for consecutive 7-day phases, and EE 0.035 mg with norgestimate 0.180/0.215/0.250 mg for consecutive 7-day phases).

What does US Patent 4,544,554 claim cover: cyclic 21/7 low-dose EE + progestogen methods?

Core answer (independent claim 1). Claim 1 covers a method of contraception that administers, to a female of childbearing age, a combined estrogen and progestogen regimen structured as:

First phase (5–8 days):

EE activity equivalent: 0.02–0.05 mg of 17α-ethinylestradiol per day
Progestogenic activity equivalent: 0.065–0.75 mg of norethindrone per day

Second phase (7–11 days):

EE activity equivalent: 0.02–0.05 mg EE per day
Progestogenic activity equivalent: 0.250–1.0 mg norethindrone per day

Third phase (3–7 days):

EE activity equivalent: 0.02–0.05 mg EE per day
Progestogenic activity equivalent: 0.35–2.0 mg norethindrone per day

No-hormone interval (6–8 days):

No estrogen and progestogen administration

Critical constraint:

“the estrogen daily dosage is the same for each period” (EE-equivalent constant across phases)

Practical claim construction points for analysis.

Phase-based dosing is essential. The claim is not a generic “any low-dose combined OC.” It is a specific three-phase escalation in progestogenic activity with a constant EE-equivalent.
Ranges are broad in the progestogen dimension but the phase windows are narrow enough to be limiting. Any design-around must keep the EE within or out of the defined EE equivalency range and/or alter the phase durations and/or remove the “same EE in each period” structure.
“Corresponding in estrogenic activity / progestogenic activity” indicates the patent treats dosing as activity-equivalent, not strictly mass, which can matter for substitutes (e.g., other estrogen forms or progestogens).

How broad are the claim ranges for estrogen and progestogen doses in US 4,544,554?

Claim 1 ranges (activity equivalents).

Claim element	Range in claim 1	What it constrains
EE-equivalent daily estrogenic activity	0.02–0.05 mg EE per day	Design-around if EE is above/below the band or EE-equivalent equivalency is argued
Progestogenic activity, Phase 1	0.065–0.75 mg norethindrone per day	Early-phase progestin low-to-mid dosing only
Progestogenic activity, Phase 2	0.250–1.0 mg norethindrone per day	Mid-phase step-up
Progestogenic activity, Phase 3	0.35–2.0 mg norethindrone per day	Final-phase higher progestin
Phase durations	Phase 1: 5–8 days; Phase 2: 7–11 days; Phase 3: 3–7 days	Must match the cyclic architecture
Hormone-free interval	6–8 days	Must include an off interval of this duration
EE constant across phases	Same EE daily dosage in each period	Any EE step-up/down across phases is outside claim 1

Dependent claims that tighten the ranges.

Claim 8 and claim 9 provide specific numeric exemplars (EE 0.035 mg; norethindrone 0.50/0.75/1.0 mg; and norgestimate 0.180/0.215/0.250 mg).

Which formulations are covered: oral administration, admixture, and specific estrogen/progestogens?

Are tablets/capsules required, or does the patent cover other routes?

Answer (claims 2 and 3). The patent explicitly includes oral administration in dependent claim 2:

Claim 2: estrogen and progestogen administered orally and each specified phase is seven days.

A separate dependent claim (claim 3) specifies admixture:

Claim 3: estrogen and progestogen administered in admixture.

This matters because many contraceptive products are oral combined pills, but not all dosing forms are orally co-administered in admixture. The independent claim 1 is not route-limited in your provided text, while dependent claims are.

What progestogens and estrogens are named in the claim set?

Progestogens in dependent claim 4.

D-norgestrel
norethindrone
progesterone
D-17β-acetoxy-13β-ethyl-17α-ethinyl-gon-4-en-3-one oxime

Estrogens in dependent claim 5.

17α-ethinylestradiol
estrone
estradiol
estriol

Narrowing in dependent claims 6–7.

Claim 6: EE is 17α-ethinylestradiol; progestogen is norethindrone
Claim 7: EE is 17α-ethinylestradiol; progestogen is D-17β-acetoxy-13β-ethyl-17α-ethinyl-gon-4-en-3-one oxime

What does claim 1 require about scheduling: does it mandate “three phases then placebo”?

Yes, in the claim logic. Claim 1 requires:

21 successive days of estrogen/progestogen administration
split into three consecutive progestogen-dosed phases with specified day windows
followed by a 6–8 day period without hormones

The “same EE each period” requirement makes this more than a typical 21/7 structure. A product that changes EE dose across phases, even if it keeps progestogen within a general combined range, can miss the “same for each period” limitation.

What are the “seven days per phase” variants and concrete dose sets in dependent claims 2, 8, 9, and 10?

Seven-day phase structure

Claim 2: oral administration; “period specified in each phase is seven days.”

This converts claim 1’s flexible phase windows into an all-seven-day architecture:

Phase 1: 7 days
Phase 2: 7 days
Phase 3: 7 days
Followed by 6–8 days without hormones (claim 2 does not fix it to 7 days in your excerpt)

Norethindrone exemplar (claim 8)

Claim 8 specifies:

EE daily dose: 0.035 mg for each 7-day period
Norethindrone daily doses:
- first 7 days: 0.50 mg
- second 7 days: 0.75 mg
- third 7 days: 1.0 mg

This is a key infringement anchor because the ranges in claim 1 include these values, and the dosing pattern is fully specified.

Norethindrone 21/7 fixed schedule (claim 9)

Claim 9 states a contraception method with:

21 successive days:
- 7 days: EE 0.035 mg + norethindrone 0.50 mg
- next 7 days: EE 0.035 mg + norethindrone 0.75 mg
- next 7 days: EE 0.035 mg + norethindrone 1.0 mg
followed by 7 days without estrogen/progestogen

This is the most operationally “product-like” embodiment in your provided claim set.

Norgestimate exemplar (claim 10)

Claim 10 specifies:

EE: 0.035 mg for 7 days, then the same for each subsequent 7-day phase
Norgestimate daily doses:
- first 7 days: 0.180 mg
- second 7 days: 0.215 mg
- third 7 days: 0.250 mg
followed by 7 days without estrogen/progestogen

This extends the claim family beyond norethindrone to norgestimate via activity-equivalence logic (“progestogenic activity corresponding to” in claim 1, with norgestimate used as a dependent variant).

What patent landscape issues matter: method-of-use claim type, activity-equivalence, and design-around?

Method-of-use claim scope

The claims you provided are framed as “a method of contraception which comprises administering …”. In US practice, this is a method-of-use claim type aimed at infringement by use/administration consistent with the claimed regimen. For enforcement, the key questions are whether accused products are marketed and used in a way that matches the claimed schedule and dosing.

Activity-equivalent dosing creates substitution risk

Claim 1’s “corresponding in estrogenic activity / progestogenic activity to X mg of 17α-ethinylestradiol / norethindrone” language increases potential argument space in two directions:

It can support infringement for non-identical mass dosing forms that are argued to produce equivalent estrogenic/progestogenic activity.
It can raise litigation complexity for alleged design-arounds that attempt to switch progestogens or estrogen identities but maintain similar activity.

Schedule manipulation is a primary design-around lever

Because claim 1 is schedule-specific (phase day windows and hormone-free interval), alternative products can try to avoid infringement by:

shifting phase durations outside the claimed day windows, and/or
changing the EE dosing pattern across phases (violating “same for each period”), and/or
eliminating the claimed no-hormone interval length.

Progestogen identity is partially constrained

Claim 4 names several progestogens, but claim 1 itself (as excerpted) is keyed to “progestogenic activity” corresponding to norethindrone. Practically, accused regimens using different progestogens will still be analyzed through activity-equivalence if the claim construction follows the language of claim 1.

What generic entry risks exist for EE + norethindrone/norgestimate triphasic regimens under this patent?

Risk profile from claim structure.

If a generic (or brand) uses a triphasic 21/7 regimen with constant EE (0.02–0.05 mg EE equivalents) and progestogen escalation in three phases matching the claimed activity ranges, the regimen falls within the independent claim.
If the generic follows the specific exemplars in claim 8–10 (EE 0.035 mg; norethindrone 0.50/0.75/1.0 or norgestimate 0.180/0.215/0.250 with 7-day phases and 7 hormone-free days), it creates a direct mapping risk to dependent claims.

What “non-infringing” often looks like in practice for this claim architecture.

Different cycle length (not 21 successive days plus 6–8 day hormone-free interval)
Different EE dosing across the three phases
Progestogen not escalating in the claimed ranges for each phase
Different oral admixture and schedule (relevant if dependent claims are asserted)

How strong is the patent estate for US 4,544,554: reliance on broad ranges vs tight exemplars?

Strength factors inherent in claim wording (from the provided claims).

Independent claim has wide numeric ranges for EE (0.02–0.05 mg) and progestogen equivalents across phases. That increases coverage against minor numeric variations.
But the claim is structurally constrained by phase duration windows and by the “same EE daily dosage in each period” requirement.
Dependent claims lock in operational regimens (seven-day phases; specific EE 0.035 mg; specific progestogen dose triplets; 7-day hormone-free interval). Those reduce ambiguity for products marketed with a canonical triphasic schedule.

What weakens scope (again, from wording only).

If an accused regimen uses EE dosing that varies across phases, it can miss claim 1 even if all doses stay within the numeric ranges.
If the hormone-free interval falls outside 6–8 days (or outside 7 days where claim 9/10 are asserted), the fit deteriorates.

Regulatory status and Orange Book analysis: what is the Orange Book status of US 4,544,554?

No Orange Book status can be stated from the provided claim text alone. The patent’s Orange Book listings, listed patents for specific FDA application numbers, and any method-of-use coding are not included in the information provided.

Patent expiration and exclusivity timing: when does US 4,544,554 lose exclusivity?

No expiration date, listed patent term, PTA/PTAB adjustments, or expiration calculations can be produced from the provided claim excerpt alone.

Which companies are challenging or licensing similar regimens under US 4,544,554?

No assignment, prosecution history, litigation caption, or licensing/settlement details are included in the provided information, so no company-specific landscape mapping can be made.

Key Takeaways

US 4,544,554 claims a triphasic low-dose combined oral contraception regimen: 21 successive days of EE + progestogen, split into three consecutive phases with specified day ranges, followed by a 6–8 day hormone-free interval.
Claim 1 is defined by constant EE daily dosage across all phases (0.02–0.05 mg EE equivalents) and phase-dependent progestogen escalation in norethindrone-equivalent activity.
Dependent claims narrow to oral administration and admixture, convert phases to seven days each, and include explicit dose triplets:
- EE 0.035 mg + norethindrone 0.50/0.75/1.0 mg (7-day phases) with 7 hormone-free days (claim 9)
- EE 0.035 mg + norgestimate 0.180/0.215/0.250 mg (7-day phases) with 7 hormone-free days (claim 10)
Design-around likelihood is primarily schedule-driven (phase day windows, hormone-free interval) and EE pattern-driven (must keep EE daily dosage the same across phases to stay within claim 1’s structure).

FAQs

What regimen pattern most directly maps to US 4,544,554 claim 9?
A 21-day triphasic oral schedule with EE 0.035 mg constant across phases plus norethindrone 0.50/0.75/1.0 mg for consecutive 7-day phases, followed by 7 days without hormones.
Can a product avoid claim 1 by changing estrogen dose across phases while keeping progestogen escalation?
Yes, claim 1 requires the estrogen daily dosage to be the same for each period.
Does claim 1 require norethindrone itself, or only norethindrone-equivalent progestogenic activity?
Claim 1 is framed in terms of progestogenic activity “corresponding to” norethindrone-equivalent dosing; dependent claims additionally identify specific progestogens.
If the progestogen ranges are met but the hormone-free interval is 5 days, is claim 1 implicated?
Not on the provided claim language, which requires 6–8 days without estrogen and progestogen in claim 1.
What is the main legal exposure for generics if they replicate the same triphasic dose triplets?
Replication of the claimed regimen structure and numeric exemplars increases risk because dependent claims 8–10 provide tight, easily mapped dosing embodiments.

References

US Patent 4,544,554. (Claim text provided in prompt).

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Details for Patent: 4,544,554

Summary for Patent: 4,544,554