US Patent 6,949,527 Scope and Claims: What’s Covered, What’s Not, and the US Patent Landscape for Aminosteroidal Neuromuscular Blockade Reversal with γ-Cyclodextrin Thiol Derivatives
US Drug Patent 6,949,527 claims a combination kit and a treatment method for inducing neuromuscular blockade with an aminosteroidal neuromuscular blocking agent and reversing that blockade with specific 6-per-deoxy-6-per-(substituted thio)-γ-cyclodextrin reversal agents (or salts). The practical claim scope is narrow around the specific cyclodextrin-thiol reversal scaffolds and the specific aminosteroidal blocking agents listed.
What exactly does US Patent 6,949,527 claim for neuromuscular block reversal kits?
Immediate answer: The patent protects kits containing:
- an aminosteroidal neuromuscular blocking agent (rocuronium, vecuronium, pancuronium, rapacuronium; salts allowed), and
- a reversal agent selected from six defined 6-per-deoxy-6-per-(R-thio)-γ-cyclodextrin derivatives (R = carboxyethyl, carboxypropyl, carboxyphenyl, carboxyphenylmethyl, propyl, sulfoethyl; salts allowed).
It also protects a method of inducing block and reversing using those same defined components.
Claim 1: Kit scope (core independent claim)
Claim 1 covers:
- A “kit” for providing neuromuscular block and reversal comprising:
- (a) an aminosteroidal neuromuscular blocking agent, and
- (b) a reversal agent selected from the enumerated γ-cyclodextrin thiol derivatives (or pharmaceutically acceptable salts).
Scope characteristics
- “Kit” is broad as a format term: it covers packaged co-administration systems, but the claim language still requires the presence of both (blocking agent + specified reversal agent).
- The reversal agent is fully enumerated, limiting design-around via alternate cyclodextrins unless they fall within the literal permutations listed.
Claim 2: Blocking agent narrowing
Claim 2 limits the aminosteroidal neuromuscular blocking agent to:
- rocuronium bromide, vecuronium bromide, pancuronium bromide, rapacuronium bromide, or pharmaceutically acceptable salts.
This means the patent, as written, does not capture other aminosteroidal neuromuscular blockers unless they are brought into the claim via a literal match to this list or via salts of these exact actives.
Claim 3: Exemplary embodiment with exact components
Claim 3 specifies:
- blocking agent = rocuronium bromide
- reversal agent = 6-per-deoxy-6per-(2-carboxyethyl)thio-γ-cyclodextrin sodium salt
This is a “golden” embodiment that can be used to show a direct commercial infringement path where a product is built around this exact pair.
How broad is the method-of-treatment claim for neuromuscular block reversal?
Immediate answer: Claim 4 protects a two-step clinical method: administer one of the specified aminosteroidal blockers, then administer an effective amount of at least one of the enumerated γ-cyclodextrin-thiol reversal agents (or salts).
Claim 4: Two-step method (core independent method claim)
The claim recites:
- (a) Induce neuromuscular block with:
- rocuronium bromide, vecuronium bromide, pancuronium bromide, or rapacuronium bromide (or salts),
- (b) Reverse the block by administering an effective amount of at least one reversal agent from the same enumerated set of 6-per-deoxy-6-per-(R-thio)-γ-cyclodextrin derivatives (or salts).
Scope characteristics
- The method is defined by sequence and functional endpoints (“inducing block” then “reversing drug-induced neuromuscular block”).
- The reversal step is captured by administering any one or more of the enumerated reversal agents, but only within the listed reversal structures.
- The claim is not written as a formulation limitation (no particle size, no route, no dosing schedule), so infringement analysis typically focuses on whether the administered reversal chemical is one of the claimed derivatives and the blocking agent is one of the claimed aminosteroidal actives.
Claim 5: Exemplary embodiment within the method claim
Claim 5 specifies:
- blocking agent = rocuronium bromide
- reversal agent = 6-per-deoxy-6-per-(2-carboxyethyl)thio-γ-cyclodextrin sodium salt
What is the patent “center of gravity”: reversal agent claims vs kit formatting?
Immediate answer: The reversal agent defines the scope.
Across Claims 1-5, the only structural trigger that drives inclusion is the specific γ-cyclodextrin thiol derivative identity. The kit and method format claims then require pairing that reversal agent with one of the listed aminosteroidal blockers.
Practical implication for freedom-to-operate (FTO)
- If a competitor uses an aminosteroidal blocker outside the listed set (or uses a different salt form that does not fall under “pharmaceutically acceptable salt thereof” of a listed bromide), it reduces risk for those specific components.
- If a competitor uses a reversal agent that is a different cyclodextrin chemistry or a differently substituted thiol derivative not listed, it is the primary design-around lever.
- If a competitor uses one of the exact claimed reversal agents but pairs it with one of the listed blockers, risk stays high regardless of how the product is packaged (kit vs co-packaged dosing system).
What are the claim limitations that can block design-around?
Immediate answer: The claims are “closed” by explicit enumeration of reversal agents and explicit enumeration of blocker actives.
Reversal agent limitations (enumerated set)
The reversal agents are explicitly limited to six compounds (and salts of those compounds). A design-around must avoid literal coverage by:
- changing the substitution pattern such that it is not one of the six enumerated R groups, or
- changing the γ-cyclodextrin-thiol scaffold so it does not meet “6-per-deoxy-6-per-(X-thio)-γ-cyclodextrin” language as written.
Blocking agent limitations (enumerated set)
The aminosteroidal blockers are limited to:
- rocuronium bromide
- vecuronium bromide
- pancuronium bromide
- rapacuronium bromide
plus pharmaceutically acceptable salts.
This creates narrower coverage than broad “any aminosteroidal neuromuscular blocker” language.
How does US Patent 6,949,527 relate to Orange Book status for the reversal agent or neuromuscular blocker?
Immediate answer: The provided claim set does not identify the corresponding FDA reference listed drug(s) and does not include patent listing data (Orange Book). Without that data, Orange Book status cannot be mapped from the claim text alone.
What can be stated from the claim scope:
- If the reversal agent is marketed as a standalone drug, the patent could be listed as a method-of-use or formulation/compound-type patent tied to that FDA application if the applicant elected to list it.
- If the marketed product is a co-formulated or co-packaged kit, listing could reflect kit-level coverage or method-of-use coverage depending on the FDA listing strategy.
(Orange Book mapping requires patent listing entries and NDA/ANDA identifiers, which are not provided in the prompt.)
Which companies or products typically sit in the infringement “crosshairs” for cyclodextrin reversal of rocuronium?
Immediate answer: The claim language indicates a specific technical theme that matches commercial efforts to reverse steroidal neuromuscular blockade using cyclodextrin derivatives, but the prompt does not provide the assignees, application numbers, or relevant FDA product names to tie to specific companies.
What can be extracted from the claims alone:
- The “most direct” infringement scenario is a product or regimen that uses rocuronium bromide plus a reversal agent that is one of the six enumerated 6-per-deoxy-6-per-(R-thio)-γ-cyclodextrin derivatives (especially the sodium salt of the 2-carboxyethyl thio derivative referenced in Claims 3 and 5).
How long is exclusivity likely to last, and when does this patent likely expire in the US?
Immediate answer: Patent term depends on filing date and any adjustments. The prompt provides the patent number and claims, but not the filing date, priority date, or prosecution history. Those inputs are required to calculate the specific expiration date with any precision.
From the number alone, the patent is a US issued patent (6,949,527), which implies it is within the typical US utility patent term structure, but a precise “date to lose exclusivity” cannot be derived from the provided information.
What is the strength profile of the patent estate based on claim structure?
Immediate answer: The patent is strong against:
- products that use the enumerated reversal agent chemistry and
- co-administered or kit-based use with the enumerated aminosteroidal blockers.
The patent is comparatively weaker against:
- reversal approaches that use different cyclodextrin derivatives (different substitutions, different backbone chemistry, or different linkage type), or
- use with blockers not among the enumerated list.
Litigation posture indicators (from claim drafting)
- The independent claims are not drafted as broad genus claims to “cyclodextrin reversal agents.” They are drafted as enumerated, specific stereochemical/chemical entities.
- The method claim requires “inducing neuromuscular block” and “reversing,” but without route, dose timing, or clinical details. That makes it easier for plaintiffs to establish infringement where the same compounds are administered in the same therapeutic sequence.
What generic or biosimilar entry risks exist under this patent, and can generics design around?
Immediate answer: The most meaningful risk is for any generic or “follow-on” reversal agent that uses an identical or salt-identical reversal compound. If a follow-on uses a non-listed reversal chemistry, the risk drops sharply.
Generic entry scenario analysis for the reversal agent
- High risk: A “generic” version of a claimed reversal agent (or an identified same active) paired with rocuronium/vecuronium/pancuronium/rapacuronium.
- Lower risk: A reversal product using a different active that is outside the enumerated set.
Generic entry scenario analysis for the blocker
- Blocking agents listed are all known aminosteroidal neuromuscular blockers. Generics for these actives are generally available or available over time. The patent does not prevent generic blockade agents by itself; it prevents the combination with the specific reversal agents and the method of reversal using those reversal agents.
How does US Patent 6,949,527 compare with adjacent patent claims that typically exist in this therapeutic area?
Immediate answer: This patent reads like an “agent identity + paired use” patent. In this therapeutic area, adjacent estates often include:
- additional cyclodextrin derivative structures,
- salt forms and purification/manufacturing controls,
- formulation and route of administration,
- dosing regimens (timing windows),
- kit packaging and administration devices.
Without additional patent numbers, family members, or assignee data, the comparison cannot be made across specific competitors or specific adjacent patents.
Key Takeaways
- US 6,949,527 protects two core claim categories: (i) a kit and (ii) a method of treatment for reversing aminosteroidal neuromuscular blockade.
- The claims are chemically enumerated for the reversal agent: specific 6-per-deoxy-6-per-(R-thio)-γ-cyclodextrin derivatives (R = carboxyethyl, carboxypropyl, carboxyphenyl, carboxyphenylmethyl, propyl, sulfoethyl) and their salts.
- The claims are functionally and pairing-limited: the reversal must pair with a blocking agent limited to rocuronium, vecuronium, pancuronium, or rapacuronium (bromides/salts).
- The most infringement-exposed scenario is a regimen or kit that administers rocuronium bromide followed by one of the enumerated γ-cyclodextrin thiol reversal agents, especially the 2-carboxyethyl thio-γ-cyclodextrin sodium salt embodiment.
FAQs
-
Does US 6,949,527 cover reversal of neuromuscular blockade induced by any aminosteroidal blocker?
No. It covers only the explicitly listed blockers (rocuronium bromide, vecuronium bromide, pancuronium bromide, rapacuronium bromide) and their salts.
-
Can a product avoid infringement by using a different cyclodextrin derivative that is not in the six-item reversal list?
The claim text requires one of the enumerated reversal agents. A different derivative would not be covered unless it falls within the specific listed structures (or salts) as written.
-
Does the patent require a specific administration route or dosing schedule?
The provided claims do not specify route or timing windows; infringement depends on administering effective amounts in the claimed sequence.
-
Is rocuronium the only blocker covered?
No. The claims include rocuronium, vecuronium, pancuronium, and rapacuronium (with salts), though Claims 3 and 5 are rocuronium-specific examples.
-
Does this patent block generic substitution of rocuronium itself?
Not by itself. The patent is directed to the kit and method combining the blocker with one of the enumerated reversal agents for blockade reversal.
References
- United States Patent 6,949,527 (claims as provided in prompt).
