US Patent 4,866,036 Landscape and Claim-Strength Analysis

What does US 4,866,036 actually claim, and how broad is it?

US 4,866,036 is directed to a combination composition: (i) a defined class of chemical compounds (formula-specified) and (ii) an antiviral anti-AIDS agent selected from a fixed list, co-formulated or co-administered in a physiologically acceptable medium. Claim 1 also limits the indication to immunocompromised humans with an AIDS-related virus, with the claimed purpose framed as enhancing host resistance against opportunistic bacterial, fungal or viral infection.

Core claim architecture (Claim 1)

Claim 1 has three key elements that drive scope and enforceability:

A “compound of the formula” with extensive substituent freedom (R groups, acyl patterns, ring/hydrogen variations, stereochemical constraints).
An antiviral selected from a defined set:
- azidothymidine (AZT)
- ansamycin
- ribavirin
- deoxycytidine
- HPA-23
- AL-721
- foscarnet
Administration in an effective amount to impart resistance against opportunistic infections in an AIDS-related immunocompromised host.

This is not a pure method-of-treatment claim on its own; it is a composition claim that couples a chemical family with one of seven named anti-AIDS antivirals.

Quantifying breadth from the claim text

The chemical portion is structured as a genus defined by:

Multiple alkyl length bands (C1-7, C1-10, C1-20, C2-30, C1-30, etc.).
Multiple heteroatom or linkage options (X = -O-, -S-, or a substituent variant).
Optional presence/absence constraints on substituents (r = 0 or 1; s = 0 or 1 with conditional restrictions).
Stereochemical limitations that are conditional on R2 and the identities of other substituents (explicit D/L assignments tied to which substituents are present).

Even without enumerating the number of distinct chemical species, the genus is clearly highly substitution-flexible. In practical infringement terms, that pushes the claim toward covering a broad family of closely-related chemical analogs that fit the structural scaffold.

Are Claims 2–4 narrower “examples,” or independent scope anchors?

Claims 2–4 are dependent claims that narrow the genus to specific prepared compounds, each described by a detailed chemical name:

Claim 2: “2-acetamido-5, 6-di-O-acetyl-2-deoxy-3-O-(D-2-propionyl-L-alanyl-D-isoglutamine)-D-glucofuranose.”
Claim 3: “2-acetamido-5-O-acetyl-2-deoxy-3-O-(D-2-propionyl-L-alanyl-D-isoglutamine)-6-O-stearoyl-D-glucofuranose.”
Claim 4: “2-acetamido-5-O-acetyl-6-O-behenoyloxyisobutyryl-2-deoxy-3-O-(D-2-propionyl-L-alanyl-D-isoglutamine)-D-glucofuranose.”

These dependent claims act as:

Technical anchor points: they map the genus to specific members.
Enforcement leverage: even if the broad formula is contested, the specific named members typically remain valuable if prior art does not anticipate them.

However, because all dependent claims still depend on Claim 1, infringement still requires the anti-AIDS antiviral selection and the AIDS-related immunocompromised host indication framing.

Does Claim 5 add enforceable breadth or mostly duplicate Claim 1?

Claim 5 is a method claim:

Administering to the host “a composition containing a compound according to claim 1.”

This is a typical composition-to-method translation. It adds little independent novelty if:

the composition is already administered (same formulation),
and the composition claim is enforceable.

The method claim can still matter in enforcement if evidence supports administration but not formulation (e.g., separate components administered in a way argued to fall under “containing a compound”).

What is the main legal risk: anticipation, obviousness, or claim indefiniteness?

1) Anticipation (hardest to clear in an “AIDS opportunistic resistance + specific antiviral set” combination)

A key defense angle for the patent is whether earlier disclosures already taught:

the same chemical scaffold/genus in combination with
one of the listed anti-AIDS antivirals,
for enhancing resistance against opportunistic infections in AIDS-related immunocompromised hosts.

Because the claim is a combination and the antiviral list is narrowly constrained, anticipation usually requires a single document disclosing the combination as claimed. That can be challenging, which is often where combination patents can survive.

2) Obviousness (most plausible vulnerability)

The obviousness question is whether it would have been routine to:

use the claimed chemical scaffold (as a known immunomodulatory or host-resistance enhancer)
together with then-standard anti-AIDS antivirals (AZT and others),
to reduce opportunistic infections.

In the late AIDS era, combination treatment logic could be attacked as predictable: antivirals reduce viral burden, and immune-augmenting compounds can be expected to improve resistance to secondary infections. The claim’s breadth on R-group substitutions could then be attacked as within the predictable chemical design space, especially if the genus corresponds to known carbohydrate-like or peptidomimetic derivatives with standard derivatization options.

3) Indefiniteness and enablement (less likely, but structural flexibility cuts both ways)

The formula uses many R groups with conditionals and permitted substituent sets. That can be defended if the specification provides adequate examples and definitions for synthesis and structure. But if the written description does not support the full permutation breadth, the genus could be attacked for not being fully enabled across the entire claim range.

How does the “antiviral selected from the group consisting of…” affect claim scope and freedom to operate?

The antiviral limitation is an unusually strong scoping mechanism.

If a competitor uses an anti-AIDS antiviral that is not in the enumerated list (for example, a different nucleoside analog or later-generation agent), it is easier to argue non-infringement of Claim 1.
If a competitor uses one of the named antivirals, infringement becomes possible if the chemical compound also fits the formula and is administered for the claimed purpose.

This creates a relatively clean binary switch for the antiviral component: either within the list, or outside it.

Claim breadth vs. enforceability: where the patent is strong

From the claim structure alone, the patent has two enforceability strengths:

Specific combination requirement
The formula-genus alone may not suffice; the antiviral must be one of seven listed agents.
Dependent claims lock into named members
Claims 2–4 provide specific chemical species. If prior art hits the broad genus, it may not hit the specific embodiments.

Where the patent is weak: typical failure modes

“Host resistance” framing may be argued as an intended-use limitation
If the compound and antiviral combination are known for treating AIDS-related complications, challengers can argue the functional language does not add a meaningful structural limitation.
Genus overbreadth could enable validity attacks
The claim allows extensive substitutions across R groups. If earlier art discloses the scaffold and the variations are routine, the claim can face an obviousness attack even if the exact species is not disclosed.
If the chemical scaffold is already disclosed, the real differentiator becomes the antiviral pairing
That means the patent’s enforceability can hinge on whether the earlier art already combined the scaffold with AZT or another listed antiviral.

What should be treated as the patent landscape “center of gravity”?

Even without pulling other documents here, the landscape analysis has a structural focus dictated by Claim 1:

Prior art needs to cover three dimensions:
1. the scaffold/genus (all or major portions of the formula),
2. AIDS or AIDS-related immunocompromise context,
3. combination with one of the explicitly named antivirals,
4. purpose or at least therapeutic positioning around opportunistic infections.

That means the most relevant prior art is likely to be in:

immunomodulatory or host-resistance chemical literature,
AIDS supportive-care and opportunistic infection prevention,
antiviral combination treatment disclosures.

Practical infringement mapping: how a competitor could design around

Because Claim 1 couples a defined chemical genus with a defined antiviral list, design-around strategies typically split into two axes:

Axis A: break the antiviral list

Use anti-AIDS antivirals not listed in Claim 1.
Or formulate a regimen where the claimed combination argument cannot be made that it is “a composition… comprising” both elements.

Axis B: break the chemical genus

Use compounds that deviate from one or more of the required structural constraints (for example, altering the scaffold so R-group substitutions no longer match the permitted sets or conditional stereochemistry rules).

The presence of conditional stereochemistry constraints is a strong technical lever: if a competitor uses a different stereochemical configuration that is outside the specified D/L conditions tied to R2 and other variables, they can potentially avoid the literal chemical match.

What is the critical business implication of the claim set?

The patent is not an all-purpose “immunocompromised opportunistic infection” composition. It is a chemistry-driven genus claim paired with named antiviral options. The business impact is:

If your development program uses one of the listed antivirals and your immunotherapy chemistry can land within the scaffold constraints, you are likely within the risk set.
If you use later-standard AIDS antivirals outside the list, the patent’s composition claims lose direct relevance, though indirect risk can still exist via other patents.

Key Takeaways

US 4,866,036 Claim 1 is a broad chemical genus claim coupled to a tight antiviral list (AZT, ansamycin, ribavirin, deoxycytidine, HPA-23, AL-721, foscarnet) for AIDS-related opportunistic infection resistance.
Claims 2–4 narrow to specific prepared compound species, preserving enforceability if the broad genus is invalidated.
Claim 5 is a method tied to administering the Claim 1 composition and is generally derivative of Claim 1.
The most credible invalidity pressure is obviousness (routine combination logic plus predictable chemical variation), while anticipation depends on whether a single prior disclosure already coupled the same scaffold with one named antiviral for the claimed use.
Freedom to operate often turns on two levers: avoid the named antiviral list and exit the chemical scaffold constraints, including the conditional stereochemical requirements.

FAQs

Is the patent limited to a single antiviral?
No. Claim 1 requires an antiviral “selected from the group consisting of” seven listed agents.
Do Claims 2–4 cover additional antivirals beyond Claim 1?
No. They depend on Claim 1, so they inherit the same antiviral limitation.
Can a competitor infringe by using a different AIDS antiviral not listed in Claim 1?
Literal infringement of Claim 1 is less likely because the antiviral is a closed “group consisting of” list.
Does Claim 5 create a broader right than Claim 1?
It is narrower in that it still requires administering a composition containing a compound that meets Claim 1’s formula and the composition inherently includes the antiviral limitation.
Which claim component most often determines design-around success?
The antiviral closed list and the conditional structural/stereochemical constraints on the formula compound.

References

[1] United States Patent 4,866,036.

Title:	Dipeptidyl 5-0,6-0-acyl-2-amino-2-deoxy-D-glucofuranose compositions and methods of use in aids-immunocompromised human hosts
Abstract:	Disclosed are specific dipeptidyl 5-0, 6-0-Acyl-2-amino-2-deoxy-D-glucofuranoses, which, either alone, or in combination with an anti-AIDS drug, e.g. azidothymidine, provide protection in human individuals whose resistance to infection has been specifically suppressed by an AIDS-related (HIV) virus, as well as help to suppress the AIDS-related infection itself.
Inventor(s):	Durette; Philippe L. (New Providence, NJ)
Assignee:	Merck & Co., Inc. (Rahway, NJ)
Application Number:	07/105,057
Patent Claims:	see list of patent claims
Patent landscape, scope, and claims summary:	US Patent 4,866,036 Landscape and Claim-Strength Analysis What does US 4,866,036 actually claim, and how broad is it? US 4,866,036 is directed to a combination composition: (i) a defined class of chemical compounds (formula-specified) and (ii) an antiviral anti-AIDS agent selected from a fixed list, co-formulated or co-administered in a physiologically acceptable medium. Claim 1 also limits the indication to immunocompromised humans with an AIDS-related virus, with the claimed purpose framed as enhancing host resistance against opportunistic bacterial, fungal or viral infection. Core claim architecture (Claim 1) Claim 1 has three key elements that drive scope and enforceability: A “compound of the formula” with extensive substituent freedom (R groups, acyl patterns, ring/hydrogen variations, stereochemical constraints). An antiviral selected from a defined set: azidothymidine (AZT) ansamycin ribavirin deoxycytidine HPA-23 AL-721 foscarnet Administration in an effective amount to impart resistance against opportunistic infections in an AIDS-related immunocompromised host. This is not a pure method-of-treatment claim on its own; it is a composition claim that couples a chemical family with one of seven named anti-AIDS antivirals. Quantifying breadth from the claim text The chemical portion is structured as a genus defined by: Multiple alkyl length bands (C1-7, C1-10, C1-20, C2-30, C1-30, etc.). Multiple heteroatom or linkage options (X = -O-, -S-, or a substituent variant). Optional presence/absence constraints on substituents (r = 0 or 1; s = 0 or 1 with conditional restrictions). Stereochemical limitations that are conditional on R2 and the identities of other substituents (explicit D/L assignments tied to which substituents are present). Even without enumerating the number of distinct chemical species, the genus is clearly highly substitution-flexible. In practical infringement terms, that pushes the claim toward covering a broad family of closely-related chemical analogs that fit the structural scaffold. Are Claims 2–4 narrower “examples,” or independent scope anchors? Claims 2–4 are dependent claims that narrow the genus to specific prepared compounds, each described by a detailed chemical name: Claim 2: “2-acetamido-5, 6-di-O-acetyl-2-deoxy-3-O-(D-2-propionyl-L-alanyl-D-isoglutamine)-D-glucofuranose.” Claim 3: “2-acetamido-5-O-acetyl-2-deoxy-3-O-(D-2-propionyl-L-alanyl-D-isoglutamine)-6-O-stearoyl-D-glucofuranose.” Claim 4: “2-acetamido-5-O-acetyl-6-O-behenoyloxyisobutyryl-2-deoxy-3-O-(D-2-propionyl-L-alanyl-D-isoglutamine)-D-glucofuranose.” These dependent claims act as: Technical anchor points: they map the genus to specific members. Enforcement leverage: even if the broad formula is contested, the specific named members typically remain valuable if prior art does not anticipate them. However, because all dependent claims still depend on Claim 1, infringement still requires the anti-AIDS antiviral selection and the AIDS-related immunocompromised host indication framing. Does Claim 5 add enforceable breadth or mostly duplicate Claim 1? Claim 5 is a method claim: Administering to the host “a composition containing a compound according to claim 1.” This is a typical composition-to-method translation. It adds little independent novelty if: the composition is already administered (same formulation), and the composition claim is enforceable. The method claim can still matter in enforcement if evidence supports administration but not formulation (e.g., separate components administered in a way argued to fall under “containing a compound”). What is the main legal risk: anticipation, obviousness, or claim indefiniteness? 1) Anticipation (hardest to clear in an “AIDS opportunistic resistance + specific antiviral set” combination) A key defense angle for the patent is whether earlier disclosures already taught: the same chemical scaffold/genus in combination with one of the listed anti-AIDS antivirals, for enhancing resistance against opportunistic infections in AIDS-related immunocompromised hosts. Because the claim is a combination and the antiviral list is narrowly constrained, anticipation usually requires a single document disclosing the combination as claimed. That can be challenging, which is often where combination patents can survive. 2) Obviousness (most plausible vulnerability) The obviousness question is whether it would have been routine to: use the claimed chemical scaffold (as a known immunomodulatory or host-resistance enhancer) together with then-standard anti-AIDS antivirals (AZT and others), to reduce opportunistic infections. In the late AIDS era, combination treatment logic could be attacked as predictable: antivirals reduce viral burden, and immune-augmenting compounds can be expected to improve resistance to secondary infections. The claim’s breadth on R-group substitutions could then be attacked as within the predictable chemical design space, especially if the genus corresponds to known carbohydrate-like or peptidomimetic derivatives with standard derivatization options. 3) Indefiniteness and enablement (less likely, but structural flexibility cuts both ways) The formula uses many R groups with conditionals and permitted substituent sets. That can be defended if the specification provides adequate examples and definitions for synthesis and structure. But if the written description does not support the full permutation breadth, the genus could be attacked for not being fully enabled across the entire claim range. How does the “antiviral selected from the group consisting of…” affect claim scope and freedom to operate? The antiviral limitation is an unusually strong scoping mechanism. If a competitor uses an anti-AIDS antiviral that is not in the enumerated list (for example, a different nucleoside analog or later-generation agent), it is easier to argue non-infringement of Claim 1. If a competitor uses one of the named antivirals, infringement becomes possible if the chemical compound also fits the formula and is administered for the claimed purpose. This creates a relatively clean binary switch for the antiviral component: either within the list, or outside it. Claim breadth vs. enforceability: where the patent is strong From the claim structure alone, the patent has two enforceability strengths: Specific combination requirement The formula-genus alone may not suffice; the antiviral must be one of seven listed agents. Dependent claims lock into named members Claims 2–4 provide specific chemical species. If prior art hits the broad genus, it may not hit the specific embodiments. Where the patent is weak: typical failure modes “Host resistance” framing may be argued as an intended-use limitation If the compound and antiviral combination are known for treating AIDS-related complications, challengers can argue the functional language does not add a meaningful structural limitation. Genus overbreadth could enable validity attacks The claim allows extensive substitutions across R groups. If earlier art discloses the scaffold and the variations are routine, the claim can face an obviousness attack even if the exact species is not disclosed. If the chemical scaffold is already disclosed, the real differentiator becomes the antiviral pairing That means the patent’s enforceability can hinge on whether the earlier art already combined the scaffold with AZT or another listed antiviral. What should be treated as the patent landscape “center of gravity”? Even without pulling other documents here, the landscape analysis has a structural focus dictated by Claim 1: Prior art needs to cover three dimensions: the scaffold/genus (all or major portions of the formula), AIDS or AIDS-related immunocompromise context, combination with one of the explicitly named antivirals, purpose or at least therapeutic positioning around opportunistic infections. That means the most relevant prior art is likely to be in: immunomodulatory or host-resistance chemical literature, AIDS supportive-care and opportunistic infection prevention, antiviral combination treatment disclosures. Practical infringement mapping: how a competitor could design around Because Claim 1 couples a defined chemical genus with a defined antiviral list, design-around strategies typically split into two axes: Axis A: break the antiviral list Use anti-AIDS antivirals not listed in Claim 1. Or formulate a regimen where the claimed combination argument cannot be made that it is “a composition… comprising” both elements. Axis B: break the chemical genus Use compounds that deviate from one or more of the required structural constraints (for example, altering the scaffold so R-group substitutions no longer match the permitted sets or conditional stereochemistry rules). The presence of conditional stereochemistry constraints is a strong technical lever: if a competitor uses a different stereochemical configuration that is outside the specified D/L conditions tied to R2 and other variables, they can potentially avoid the literal chemical match. What is the critical business implication of the claim set? The patent is not an all-purpose “immunocompromised opportunistic infection” composition. It is a chemistry-driven genus claim paired with named antiviral options. The business impact is: If your development program uses one of the listed antivirals and your immunotherapy chemistry can land within the scaffold constraints, you are likely within the risk set. If you use later-standard AIDS antivirals outside the list, the patent’s composition claims lose direct relevance, though indirect risk can still exist via other patents. Key Takeaways US 4,866,036 Claim 1 is a broad chemical genus claim coupled to a tight antiviral list (AZT, ansamycin, ribavirin, deoxycytidine, HPA-23, AL-721, foscarnet) for AIDS-related opportunistic infection resistance. Claims 2–4 narrow to specific prepared compound species, preserving enforceability if the broad genus is invalidated. Claim 5 is a method tied to administering the Claim 1 composition and is generally derivative of Claim 1. The most credible invalidity pressure is obviousness (routine combination logic plus predictable chemical variation), while anticipation depends on whether a single prior disclosure already coupled the same scaffold with one named antiviral for the claimed use. Freedom to operate often turns on two levers: avoid the named antiviral list and exit the chemical scaffold constraints, including the conditional stereochemical requirements. FAQs Is the patent limited to a single antiviral? No. Claim 1 requires an antiviral “selected from the group consisting of” seven listed agents. Do Claims 2–4 cover additional antivirals beyond Claim 1? No. They depend on Claim 1, so they inherit the same antiviral limitation. Can a competitor infringe by using a different AIDS antiviral not listed in Claim 1? Literal infringement of Claim 1 is less likely because the antiviral is a closed “group consisting of” list. Does Claim 5 create a broader right than Claim 1? It is narrower in that it still requires administering a composition containing a compound that meets Claim 1’s formula and the composition inherently includes the antiviral limitation. Which claim component most often determines design-around success? The antiviral closed list and the conditional structural/stereochemical constraints on the formula compound. References [1] United States Patent 4,866,036. More… ↓ ⤷ Start Trial

Applicant	Tradename	Biologic Ingredient	Dosage Form	BLA	Approval Date	Patent No.	Expiredate
Hoffmann-la Roche Inc.	PEGASYS COPEGUS COMBINATION PACK	peginterferon alfa-2a and ribavirin		125083	June 4, 2004	⤷ Start Trial	2007-10-05
Schering Corporation A Subsidiary Of Merck & Co., Inc.	PEGINTRON/ REBETOL COMBO PACK	peginterferon alfa-2b and ribavirin		125196	June 13, 2008	⤷ Start Trial	2007-10-05
>Applicant	>Tradename	>Biologic Ingredient	>Dosage Form	>BLA	>Approval Date	>Patent No.	>Expiredate

Patent: 4,866,036

Summary for Patent: 4,866,036