Details for Patent: 4,879,288

US Patent 4,879,288 (United States): Scope of Claims, Claim Construction Hooks, and the US Patent Landscape Around the Covered Compounds and Salts

US Patent 4,879,288 claims a specific chemical entity defined by “formula II” (and its acid addition salts), with dependent coverage for “pharmaceutically acceptable” salts and specific salt embodiments (hemifumarate and hydrochloride), plus broad composition and medical use claims for psychosis and hyperactivity. The claim set is structured as a classic compound-of-formula core with salt dependencies and then high-level therapeutic use coverage via generic “managing”/“treating” language. The patent’s effective enforceable scope in the US is therefore anchored to (1) how “formula II” is construed, (2) which stereochemical and substitution variables are actually inside the formula definition, (3) whether an accused product falls within any acid addition salt embodiment, and (4) whether any asserted pharmaceutical use claim is implicated through product label, induced prescribing, or actual administration evidence.

What is US Patent 4,879,288 and what do claims 1-4 cover (compound and salt scope)?

Featured snippet answer: Claims 1-4 cover a “compound of formula II” and acid addition salts, including pharmaceutically acceptable acid salts, specifically hemifumarate and hydrochloride embodiments.

Claim 1: “A compound of formula II … and acid addition salts thereof”

Claim 1 is the primary coverage grant. It has two major coverage vectors:

1. Core molecule: “A compound of formula II.”
2. Salt form: “and acid addition salts thereof.”

From a scope perspective, claim 1 is not limited to a single salt. It covers any acid addition salt of the formula II compound, subject to later dependent claim narrowing for “pharmaceutically acceptable” and specific salt species.

Key enforceability implications:

• If the defendant sells the free base only, claim 1 may still be tested against whether the free base qualifies as “a compound of formula II.” The salt language is additive, not replacement, but the claim structure still requires the accused compound be the formula II compound; salt form affects whether claim 1’s salt coverage is implicated.
• If the defendant sells a salt not listed in claims 3-4, claim 1 may still capture it as long as it is an “acid addition salt” of the formula II compound (and the claim is read broadly enough to treat all acid addition salts as within the claim).

Claim 2: “pharmaceutically acceptable acid addition salts”

Claim 2 narrows claim 1 from “acid addition salts” to pharmaceutically acceptable acid addition salts. In practice, this creates a two-tier structure:

• Broader salt coverage: claim 1 includes acid addition salts generally.
• Narrower salt coverage: claim 2 includes pharmaceutically acceptable acid addition salts.

A litigation strategy built around salt form typically pivots on whether the accused salt is “pharmaceutically acceptable.” If the competitor uses a non-traditional or less conventional counterion, they may argue it falls outside “pharmaceutically acceptable” unless the record shows that counterion is within that acceptability concept.

Claim 3: “hemifumarate salt”

Claim 3 is a specific salt species dependent on claim 2. It is enforceable as to:

• hemifumarate counterion
• applied to the formula II compound
• constrained by the “pharmaceutically acceptable” limitation (because claim 3 depends on claim 2)

Claim 4: “hydrochloride salt”

Claim 4 similarly covers a specific salt species:

• hydrochloride counterion
• dependent on “pharmaceutically acceptable acid addition salts”

Net effect: if the market has a hydrochloride or hemifumarate commercial form, those embodiments are directly claimed. That also increases the likelihood that an Orange Book listing (if any exists for a US NDA) includes one of these salts, which matters for FDA regulatory linkage and later use in injunction pressure.

How do claims 5-8 expand from chemistry into use claims (composition and method-of-use scope)?

Featured snippet answer: Claims 5-8 cover pharmaceutical compositions containing the claim 2 compound for managing psychotic conditions or reducing hyperactivity, and methods of treating psychosis or hyperactivity by administering an effective amount of the claimed composition.

Claims 5-8 shift from chemical structure to functional medical use language. In enforcement terms, these claims require mapping of:

• whether the administered product contains the claimed compound (claim 2 compound in a composition)
• whether the use matches psychosis management or hyperactivity reduction
• whether the “effective amount” threshold is met (a customary clinical-quantity issue)
• whether “administering” is evidenced by actual practice or inducement/labeling in the US context

Claim 5: Composition for psychotic conditions

Claim 5 recites a pharmaceutical composition comprising:

• the compound of claim 2
• an amount sufficient to “manage a psychotic condition”
• with a “non-toxic pharmaceutically acceptable diluent or carrier”

Scope expansion points:

• “manage” is broader than “cure.” It can cover stabilization, symptom reduction, and ongoing control.
• The claim is not limited to specific dosage units, routes, or formulation type beyond inclusion of a “diluent or carrier.”

Practical constraining factors often arise from the patent specification’s described embodiments and from how “psychotic condition” is interpreted. But the claim text is broad: it is therapeutic, not mechanistic.

Claim 6: Composition for hyperactivity

Claim 6 is parallel to claim 5:

• compound of claim 2
• amount sufficient to “reduce hyperactivity”
• non-toxic pharmaceutically acceptable diluent or carrier

This claim type can create enforcement leverage if a competitor’s product label includes hyperactivity indications or if real-world use data supports the functional use.

Claim 7: Method of treating psychosis

Claim 7 covers:

• “administering to the mammal an effective amount”
• “a composition of claim 2”

There is a subtle drafting issue: claim 7 refers to “a composition of claim 2,” but claim 2 is a salt class claim, not a composition. In claim-structure terms, this likely means the composition includes the claim 2 compound. In litigation, this becomes a claim construction question. The net effect is still that the method is tied to administration of the salt-form compound.

Claim 8: Method of treating hyperactivity

Claim 8 mirrors claim 7:

• administer an effective amount of the composition tied to claim 2 compound
• to treat hyperactivity

Mammal scope

All method and composition claims specify “a living mammal.” That is typically broad enough to include humans and veterinary species. In US litigation, the most relevant infringing acts are usually human administration and promotion, but the claim text itself is not restricted to humans.

What claim construction questions determine infringement risk under 4,879,288?

Featured snippet answer: Infringement risk turns on how “formula II” variables are construed, how acid addition salts are classified as pharmaceutically acceptable, and whether accused products are administered for psychosis management or hyperactivity reduction.

“Formula II” scope: structural boundary and substitution variables

The claims as provided do not reproduce the full formula, so the exact structural reach cannot be restated here. For infringement analysis, “formula II” scope is the primary battleground:

• does the formula include optional stereochemistry?
• does it include interchangeable substituents or marked variable groups?
• are the salt forms included inherently by structure or only by explicit salt definition?

Any competitor design-around that changes the formula variables outside “formula II” is a direct path to non-infringement for claims 1-8. If they remain within formula II but change salt counterions, claim 1 and possibly claim 2 still capture as acid salts; claims 3 and 4 only capture those specific salts.

Salt classification: “acid addition salt” and “pharmaceutically acceptable”

Two classification questions drive exposure:

• Is the accused counterion an acid addition salt of the formula II compound?
• Is it “pharmaceutically acceptable acid addition salt”?

If the competitor uses a different acid (for example, a different fumarate variant, acetate, tosylate, methanesulfonate, etc.), claim 1 may still capture if it is an acid addition salt, and claim 2 may still capture if it is pharmaceutically acceptable.

Therapeutic scope: “manage” and “reduce”

“Manage a psychotic condition” and “reduce hyperactivity” are functional. That makes infringement potentially label- and practice-dependent:

• If the competitor’s labeling or marketing describes those effects, it strengthens linkage to the claimed use.
• If the competitor argues their use case is different (different diagnosis, different symptom management framing), that can create factual disputes. Still, the broad language is designed to cover symptom control rather than specific mechanistic endpoints.

How many patents are likely in the US “compound-salt-use” cluster around 4,879,288, and what types of claims typically surround it?

Featured snippet answer: The typical US patent estate around a compound-of-formula core like 4,879,288 clusters into (a) additional chemistry patents (process, intermediates), (b) formulation and salt-species continuation filings, (c) expanded use or regimen claims, and (d) polymorph/solid-state claims, sometimes with FDA regulatory tie-ins through Orange Book listings.

With only the claim text provided, a quantified count of related US patents cannot be produced here. What can be stated from the claim architecture is that an estate matching this claim style usually attracts follow-on filings. The follow-on patterns that matter for business decisions:

1) Salt-species and polymorph continuation filings

Because claims 3 and 4 single out hemifumarate and hydrochloride, competitors often explore alternative salts and solid-state forms. Patent estates frequently respond with:

• additional salt species claims
• polymorph and hydrate claims
• solid form patents tied to specific manufacturing and storage stability

2) Process and intermediate patents

Chemical lead compounds typically have:

• synthesis route patents
• purification and intermediate patents These can be essential for “manufacturing IP barriers” even if the competitor can avoid the exact salt claims.

3) Use and dosing regimen continuations

Method-of-use claims for psychosis and hyperactivity are commonly followed by:

• narrower diagnostic framing
• pediatric-specific use
• specific dosing schedules
• combination therapy claims

4) Formulation improvements

Because claims 5-6 are broad to “diluent or carrier,” later patents often cover:

• dosage forms (tablet, capsule, suspension, injectables)
• controlled-release profiles
• bioavailability-enhancing formulations

What regulatory hooks matter for enforcement: Orange Book status and FDA labeling linkage?

Featured snippet answer: For compound-salt and method-of-use claims like this, enforcement leverage typically hinges on whether the compound is listed in the Orange Book and whether labeling tracks “psychosis” and “hyperactivity” symptom reduction.

Two practical linkage points:

• Orange Book listing: If the claimed compound (or approved product containing it) is listed, the NDA/ANDA pathway can bring patent infringement allegations into the Paragraph IV context. The specific salt form matters if the listed formulation is hemifumarate or hydrochloride.
• Label alignment: Method-of-use claims are triggered by actual administration for the claimed purpose. FDA-approved labeling that states efficacy for psychosis or hyperactivity symptom reduction can materially strengthen infringement arguments.

What generic entry risks exist if a competitor launches a Paragraph IV for the claimed compound?

Featured snippet answer: A generic or follow-on salt manufacturer faces direct risk if it sells a product that contains the formula II compound in an acid addition salt (especially pharmaceutically acceptable hemifumarate or hydrochloride) and if the product is used or labeled for psychosis management or hyperactivity reduction.

Risk scenarios typically split into two categories:

Scenario A: “Biosalt and form” is within the claim

• The competitor uses a pharmaceutically acceptable acid addition salt of formula II (including hemifumarate or hydrochloride).
• Then claims 1-4 are in play for the product itself.
• Claims 5-8 become additional risk if labeling or induced practice matches the symptom-management uses.

Scenario B: “Counterion design-around,” but claim 1 still reads through

• If the competitor uses a different acid but still an acid addition salt that is pharmaceutically acceptable, claim 1 and claim 2 can still capture.
• Avoiding claims 1-2 typically requires moving outside “acid addition salt” classification or moving outside formula II.

How does claim scope compare with typical competitive design-around strategies?

Featured snippet answer: 4,879,288 is difficult to work around by salt selection alone; the critical design-around is structural. Salt changes can avoid claims 3-4 but often not claim 1-2.

Design-around levers and how the claims respond

• Changing the core structure outside formula II: strongest path to avoid all claims.
• Changing the counterion (salt): may avoid claim 3-4 but often remains within claim 1 (acid addition salt) and claim 2 (pharmaceutically acceptable acid addition salt).
• Changing the intended use: can reduce risk of claims 5-8 but not claims 1-4; also depends on labeling and actual administration evidence.
• Changing dosage form only: does not avoid claims 5-8 as long as it still includes “non-toxic pharmaceutically acceptable diluent or carrier” and administers an effective amount for the claimed use.

Litigation and licensing landscape: what matters most for strategy around 4,879,288?

Featured snippet answer: For a compound-plus-salt-plus-use patent like 4,879,288, litigation and licensing typically resolve around (1) structural infringement of formula II, (2) salt counterion and pharmaceutically acceptable classification, and (3) whether the FDA-labeled use or real-world use satisfies psychosis/hyperactivity symptom management.

Even without a verified docket list here, business-relevant settlement terms in this profile generally include:

• carve-outs for non-asserted salt forms
• permissions for generics conditioned on labeling changes (use carve-out)
• royalty-bearing licenses for specific dosage forms
• interim injunction or launch-trigger commitments tied to patent validity or non-infringement

Technical subtopics: what product attributes determine whether a competing compound “practices” these claims?

Featured snippet answer: For claims 1-4, molecular identity and salt form determine infringement; for claims 5-8, product formulation is necessary and therapeutic purpose matters.

Product identity mapping (claims 1-4)

• exact compound identity vs formula II embodiment
• salt counterion and whether it qualifies as an acid addition salt
• whether the salt is pharmaceutically acceptable

Formulation and use mapping (claims 5-8)

• whether the product contains the compound of claim 2 (not just a related analog)
• whether the dose is “effective”
• whether the use is “managing” psychosis or reducing hyperactivity

Key Takeaways

• US 4,879,288 is a compound-of-formula patent with direct salt coverage (acid addition salts) and explicit salt species (hemifumarate, hydrochloride).
• The enforceable core is “formula II.” Salt changes alone may avoid only specific dependent claims (hemifumarate/hydrochloride) while leaving broad claim 1-2 exposure.
• Claims 5-8 add therapeutic use coverage framed broadly around psychosis management and hyperactivity reduction, increasing leverage when labeling and actual use mirror those endpoints.
• Competitive strategy should focus first on avoiding “formula II” infringement; second on salt/counterion and “pharmaceutically acceptable” classification; third on labeling and intended use to mitigate method-of-use and composition claims.

FAQs

1) Does claim 1 cover only hydrochloride and hemifumarate, or any acid addition salt?
Claim 1 covers the formula II compound and “acid addition salts thereof,” not limited to hydrochloride or hemifumarate.

2) If a generic uses a different counterion salt, does it avoid the patent?
It may avoid claims 3 and 4, but it still faces claim 1-2 risk if the alternative counterion is an acid addition salt and pharmaceutically acceptable.

3) Are the method-of-use claims limited to humans?
No. They cover “a living mammal,” which includes humans.

4) What product labeling issue is most important for claims 5-8?
Whether labeling or promoted intended use supports “manage a psychotic condition” or “reduce hyperactivity” in a mammal.

5) Is avoiding the salt form enough to avoid claims 5-8?
No. Claims 5-8 require the composition to include the claim 2 compound (the pharmaceutically acceptable acid addition salt form), so counterion changes must avoid the claim 2 scope as well.

References

1. United States Patent 4,879,288.