US Patent 4,341,774 Landscape and Claim Scope: Cholecalciferol/D-Bile Acid? Immunosuppression Methods in Humans

Executive summary: US 4,341,774 is a method-of-treatment patent that claims immunosuppression in humans by administering cholecalciferol (vitamin D3) and/or derivatives at defined daily doses (0.25 to 10 μg/day; narrower 0.5 to 5 μg/day) and/or achieving blood concentrations (0.01 to 1 μg/mL), including specific clinical settings (autoimmune disease and graft rejection). The claim set is written to capture both (i) route-independent “administering” approaches and (ii) functional immunosuppression endpoints, while tying coverage to quantitative exposure ranges. This structure creates both a narrow numeric “design space” for dosing/exposure and a broader hook for “immunosuppression in humans” using vitamin D or derivatives.

What does US 4,341,774 claim cover: immunosuppression with cholecalciferol in humans?

Core invention (claim 1): A method for immunosuppression in humans comprising administering cholecalciferol and/or its derivative to a human needing immunosuppression, in an amount sufficient to suppress abnormal rise in immunological function.

How claim 1 is likely construed

Claim 1 is a classic “medical use” method claim with three functional elements:

Human immunosuppression need
- Trigger: “in a human in need of immunosuppression.”
- This is broad in indication language because it does not restrict to a particular disorder in claim 1.
Active ingredient scope
- Covers cholecalciferol and “its derivative.”
- “Derivative” is typically where the real scope sits. If “derivative” is defined by the specification as specific vitamin D analogs (or chemical modifications), claim 1 may reach beyond cholecalciferol to analogs that fall within that definition.
- If the specification uses broad language, the derivative term can be expansive and can reach analogs used clinically (eg, calcitriol or analogs), but the claim’s practical reach depends on the written description and enablement.
Functional endpoint
- “amount sufficient to suppress abnormal rise in immunological function”
- This is an efficacy-based functional limitation. In litigation, the key dispute usually becomes whether the accused regimen produces immunologic suppression consistent with the claim language, not whether the patient has the exact named diagnosis.

What claim 1 does not require

It does not require a specific route, dosage form, titration schedule, or monitoring assay in the claim text.
It does not require a specific immunologic biomarker in the claim text.
It does not require a specific immune condition in claim 1 beyond “in need of immunosuppression.”

How narrow are US 4,341,774 dosing and blood concentration limits?

Exclusive coverage hinge: Claims 2–4 add quantitative boundaries. These are where freedom-to-operate analysis usually narrows.

Claim 2: 0.25 to 10 μg/day per adult

Claim 2 requires the amount of cholecalciferol/derivative to be within:

0.25 to 10 μg/day per adult

This maps to vitamin D3 exposures that can include low-dose to moderate-dose regimens in many vitamin D contexts, but claim language focuses on immunosuppression, not bone/mineral indications.

Claim 3: 0.5 to 5 μg/day per adult

Claim 3 narrows claim 2 to:

0.5 to 5 μg/day per adult

This narrower “sweet spot” will matter for generic or compounding regimens aiming to stay outside the patent’s numeric boundaries.

Claim 4: blood concentration 0.01 μg/mL to 1 μg/mL

Claim 4 adds an exposure-based limitation:

blood concentration of active ingredient between 0.01 μg/mL and 1 μg/mL

This introduces a second infringement axis:

Even if dosing is outside the numeric daily range, a regimen could potentially still fall within claim 4 if it achieves concentrations within range.
In practice, blood levels can vary with patient factors, assay variability, timing of sample collection, and derivative-specific pharmacokinetics. But the claim is still numerically bounded.

Do US 4,341,774 claims cover autoimmune disease indications and which ones?

Yes, via dependent claims 5 and 6.

Claim 5: autoimmune disease

Claim 5 restricts claim 1 to:

a human having an autoimmune disease

This still leaves many autoimmune conditions outside the enumerated list in claim 6, but the dependent claim still requires proof of autoimmune status.

Claim 6: specific autoimmune diseases

Claim 6 further specifies:

chronic thyroiditis
autoimmune hemolytic rheumatoid arthritis
systemic lupus erythematosus

This set functions in two ways:

Direct coverage for these exact indications if the dosing/exposure limitations of dependent claims are also met (depending on which claims are asserted).
Potential interpretive guidance for what the patent considers immunologic abnormalities consistent with “abnormal rise in immunological function,” which can affect “functional” claim 1 disputes.

Does US 4,341,774 cover graft rejection and what claim language matters?

Yes, via dependent claim 7.

Claim 7: suppression of graft rejection

Claim 7 limits claim 1 to:

a human in need of suppression of graft rejection

This is the transplantation use hook and is often relevant to immunosuppressive regimens where vitamin D analogs are explored as adjuncts.

Practical infringement vectors

If a regimen is used to prevent rejection, and vitamin D3/derivative is administered at amounts sufficient to suppress abnormal immunological function, claim 7 is activated.
If the regimen is only used for vitamin D deficiency in transplant patients without immunosuppression as a functional treatment objective and without meeting dosing/exposure limitations, a defendant can argue that claim elements are not met. Claim 7 is still broad because it does not require the word “prophylaxis,” only that the human is “in need of suppression.”

How many distinct claim coverage buckets exist in US 4,341,774?

Based on the claim text provided, the patent divides into these coverage “buckets”:

Vitamin D3/derivative immunosuppression method (broad)
- Claim 1
Daily dosing-limited method
- Claims 2 and 3 (0.25 to 10 μg/day; 0.5 to 5 μg/day)
Blood concentration-limited method
- Claim 4 (0.01 to 1 μg/mL to 1 μg/mL)
Indication-limited autoimmune method
- Claims 5 and 6 (autoimmune disease; chronic thyroiditis; autoimmune hemolytic rheumatoid arthritis; systemic lupus erythematosus)
Indication-limited transplant method
- Claim 7 (suppression of graft rejection)

From a litigation or licensing perspective, this is favorable to a patentee because it provides multiple independent pathways to infringement: dosing-limited, exposure-limited, and indication-limited.

What is the legal and procedural risk profile for enforcing US 4,341,774 in the US?

Method-of-treatment enforcement

US method patents like this generally face the same core enforcement framework:

infringement occurs by using a claimed method (administering a regimen), not merely by selling a product.
This creates enforcement leverage against providers or downstream actors, but also practical difficulties for claim proof in civil litigation.

Key dispute points likely to arise

“Derivative” scope
- Whether an accused compound is “cholecalciferol and/or its derivative” depends on how “derivative” is defined in the written description and interpreted in claim construction.
Functional immunosuppression
- Defendants often argue the treatment did not suppress “abnormal rise” in immunological function as claimed.
- Plaintiffs tend to rely on clinical and mechanistic evidence described in the patent or in contemporaneous clinical literature.
Quantitative dosing and concentration measurement
- Claims 2–4 create objective numerical anchors.
- For claim 4, proving blood concentrations within the specified range becomes a factual issue tied to sampling time and lab methods.

Anticipation/obviousness risk (conceptual)

Because the patent claims an immunosuppression use of vitamin D, prior art vitamin D immunomodulation literature may attack:

novelty of the overall concept,
obviousness of applying vitamin D to immunosuppression contexts,
specific numeric dose ranges.

A strong defense posture usually depends on whether the patent demonstrates non-obviousity of:

the dosing/exposure windows,
the identified autoimmune/transplant contexts,
the clinical effect tied to the claimed functional endpoint.

What patent estate issues matter most when mapping competitors around US 4,341,774?

Two-dimensional map: (i) use patents and (ii) compound/delivery method patents.

1) Use patents (indication and dosing/exposure)

Claims 1–7 are centered on:

immunosuppression using vitamin D3/derivatives,
numeric dosing and blood levels,
autoimmune and graft rejection settings.

Competitors must evaluate whether their regimen:

uses vitamin D3 or a “derivative” within the patent’s defined meaning,
targets immunosuppression rather than bone/mineral indications only,
falls within dosing or concentration windows.

2) Formulation and dosing regimen patents

Even if a competitor uses a compound outside the scope of “derivative,” it may still be relevant if:

a formulation is used to achieve blood concentrations in the claim range, or
the regimen is combined with other agents in a manner that still produces the claimed functional immunosuppression.

3) Biosimilar relevance

This is not a biologic patent. Biosimilar risk is structurally low. The relevant comparison is generic small-molecule or analog competition, not biosimilar entry.

When could generic or alternative-use risk surface relative to US 4,341,774?

This analysis requires the patent’s expiration date, which cannot be derived from the claim text alone. With method patents like this, entry risk usually comes in two waves:

Compound competition risk
- Generic vitamin D3 or common vitamin D derivatives are widely available.
- The patent claims the method, so availability of the drug does not automatically enable infringement-free practice.
Method competition risk
- Clinicians can use vitamin D3 off-label for immune modulation unless a covered method claim is asserted.
- The real risk is use patterns: if a regimen matches the claim’s dosing/exposure and immunosuppression endpoint, infringement exposure increases.

A correct “generic entry scenario” timeline cannot be stated without USPTO records for this specific patent (filing date, issue date, maintenance, terminal disclaimer, and any regulatory exclusivity overlays).

Which companies are likely to be adjacent to this claim space?

Given only the provided claim text, company identification cannot be done without external patent and litigation records tied to US 4,341,774 and related filings. Producing named defendants or challengers would require verifiable linkage to the patent family, citing assignments, and any Paragraph IV or other active litigation dockets, none of which are available in the prompt.

How strong is US 4,341,774’s claim structure for licensing or litigation?

Strength factors

Multiple dependent claim pathways: dosing (claims 2–3), blood exposure (claim 4), and two indication buckets (autoimmune and graft rejection).
Objective numerical limitations in claims 2–4 help enforcement compared with purely functional claims.
Broad claim 1 hook covers any immunosuppression use meeting functional endpoint, while dependent claims narrow to specific treatment contexts.

Vulnerabilities

Derivative breadth can generate claim construction disputes. Overbroad “derivative” definitions can draw invalidity arguments if the specification does not support the full range.
Prior art immunomodulation of vitamin D could undermine novelty/obviousness if the claimed dosing windows and specific immunosuppression outcomes were already taught.
Functional immunosuppression can be disputed clinically, requiring proof that the accused regimen “suppresses abnormal rise” in immunological function.

What is the scope of “abnormal rise in immunological function” in claim 1?

This is the functional core and typically becomes a battleground:

Plaintiffs argue the patient had an immune dysregulation state and the treatment reduced immune activity consistent with immunosuppression.
Defendants argue vitamin D treatment corrected immune markers without meeting “immunosuppression” as understood by the patent, or that patient selection and endpoint assays did not align.

The claim’s breadth makes it easier for plaintiffs to map evidence if the patent’s specification ties vitamin D to measurable immune suppression effects. That linkage cannot be confirmed from the prompt alone.

Related claim design: how “administering in amount sufficient” interacts with numeric claims

Claim 1 is functional and “amount sufficient” can be satisfied even if dosing is not explicitly in the numeric ranges.
Claims 2–4 constrain the amount by dose or blood concentration.
In litigation strategy, plaintiffs often plead:
- infringement of claim 1 based on overall functional evidence,
- infringement of claims 2–4 based on numerical matching,
- plus indication-based dependent claims (5–7) where patient records exist.

This layering makes the case more resilient to partial factual failure.

US patent 4,341,774: structured claim chart (provided claims only)

Claim	Scope element	Key limitation
1	Method for immunosuppression	Administer cholecalciferol and/or derivative to human in need; amount sufficient to suppress abnormal rise in immunological function
2	Dosage window	0.25 to 10 μg/day per adult
3	Narrower dosage window	0.5 to 5 μg/day per adult
4	Exposure window	Blood concentration 0.01 μg/mL to 1 μg/mL
5	Indication bucket	Human has autoimmune disease
6	Specific autoimmune diseases	Chronic thyroiditis; autoimmune hemolytic rheumatoid arthritis; systemic lupus erythematosus
7	Indication bucket	Suppression of graft rejection

Key Takeaways

US 4,341,774 is a human method-of-immunosuppression patent anchored on administering cholecalciferol and/or its derivative to suppress abnormal immune function.
The strongest “objective” elements are the numeric dose and exposure limits in dependent claims:
- 0.25 to 10 μg/day,
- 0.5 to 5 μg/day,
- blood concentration 0.01 to 1 μg/mL.
The patent creates indication-specific enforcement hooks for autoimmune diseases (including listed conditions) and graft rejection.
The primary litigation and licensing pressure points are: what qualifies as a “derivative,” whether the clinical effect qualifies as immunosuppression, and whether patient dosing/exposure hits the claimed windows.

FAQs

Can off-label vitamin D use for autoimmune conditions infringe US 4,341,774?
If the off-label regimen matches the claim’s dosing/exposure and is used for immunosuppression by suppressing abnormal immunological function, it can fall within the method claims.
What is the difference between infringing based on daily dose vs blood concentration under this patent?
Claims 2–3 require a daily dose range, while claim 4 requires a blood concentration range. A regimen could potentially satisfy one without the other depending on pharmacokinetics and sampling.
Does the patent require specific biomarkers or lab assays?
The provided claim text does not require specific biomarkers; it uses functional immunosuppression language, leaving proof to clinical context and evidence.
Are immune-modulating vitamin D derivatives outside “cholecalciferol derivatives” automatically safe?
Safety depends on claim construction of “derivative” in the written description and whether the accused compound falls within that defined scope.
Does US 4,341,774 protect formulations or only the method of treatment?
Based on the provided claims, it protects the method of immunosuppression by administering cholecalciferol/derivative, not a formulation per se.

References

No references are included because no external sources (USPTO records, Orange Book listings, litigation dockets, or patent family documents) were provided in the prompt.

Foriegn Application Priority Data
Foreign Country	Foreign Patent Number	Foreign Patent Date
Japan	54-101211	Aug 10, 1979

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Japan	S5626820	⤷ Start Trial
Japan	S6365646	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 4,341,774

Summary for Patent: 4,341,774