Details for Patent: RE29618
Summary for Patent: RE29618
| Title: | Suppression of cardiac ventricular fibrillation and cardiac arrhythmias with bretylium tosylate | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Abstract: | A method for suppressing cardiac ventricular fibrillation and cardiac arrhythmias in animals, both human and otherwise, by administration of ortho-bromo benzyl ethyldimethylammonium p-toluene-sulfonate (bretylium tosylate). The drug may be administered prophylactically in the prevention of or in the treatment of ventricular fibrillation or cardiac arrhythmias. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Inventor(s): | Marvin B. Bacaner | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Assignee: | University of Minnesota System | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Application Number: | US05/781,654 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Patent Claim Types: see list of patent claims | Use; Formulation; Delivery; | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Patent landscape, scope, and claims: | United States Drug Patent RE29618: Scope, Claim Construction, Expiration, and Bretylium Tosylate Patent LandscapeUnited States Reissue Patent RE29618 covers the use of bretylium tosylate to suppress ventricular fibrillation and ventricular arrhythmias, including ventricular tachycardia and ventricular premature beats. Its claims are method-of-treatment claims, not composition, formulation, manufacturing, or product-by-process claims. The patent is long expired and does not create current U.S. exclusivity for bretylium tosylate products. The principal commercial and legal conclusion is that RE29618 has historical relevance but no material present-day blocking effect on generic bretylium tosylate development, manufacture, FDA approval, or marketing. What does United States Patent RE29618 protect?RE29618 protects administering bretylium tosylate to a living subject in an amount sufficient to restore sinus rhythm or suppress specified ventricular arrhythmias.
The patent does not claim bretylium tosylate as a chemical compound. It does not claim a specific injectable formulation, concentration, container, manufacturing process, salt-selection process, or pharmaceutical composition. How should the RE29618 claims be construed?Claim 1Claim 1 is the broadest original treatment claim. A practicing entity would need to establish:
The claim is functional in two respects. It defines the dose by the therapeutic result, and it requires restoration of sinus rhythm. A product label that merely states that bretylium tosylate may be used for ventricular arrhythmias would not automatically establish infringement. The relevant question would be whether the accused conduct involves the claimed administration and therapeutic purpose. The phrase "small but effective amount" has little independent limiting value because the claim immediately defines the required amount as one sufficient to restore sinus rhythm. The claim therefore depends on the clinical result rather than a fixed concentration or dose. Claims 2, 3, and 4Claim 2 narrows claim 1 to approximately 5-50 mg/kg. Claims 3 and 4 narrow the emergency-use scenario further. Claim 3 requires:
Claim 4 substitutes acute coronary insufficiency for acute coronary occlusion. These claims are materially narrower than claim 1. A modern injectable product could fall within the numerical dose range but still avoid claims 3 and 4 if the clinical indication, patient condition, route, or emergency procedure differs. Conversely, the use of an aqueous injectable product does not alone satisfy all limitations. Claim 5Claim 5 covers oral dosing at intervals ranging from approximately every six to eight hours to once daily. It is distinct from the IV emergency claims and does not require acute coronary occlusion, acute coronary insufficiency, vigorous massage, or electrical defibrillation. The claim is directed to a dosing regimen, not an oral dosage-form composition. It does not expressly require tablets, capsules, solutions, or a particular excipient system. Claims 6 through 13Claims 6 through 13 divide the broad therapeutic concept into separate fibrillation and arrhythmia categories. Claim 6 covers ventricular fibrillation. Claim 7 adds IV administration. Claim 8 covers ventricular arrhythmias generally. Claims 9 through 12 identify particular arrhythmias, including ventricular tachycardia, ventricular premature beats, ventricular extrasystoles, and atrioventricular dissociation. Claim 13 adds IV administration to claim 8. Claims 6 and 8 are functionally similar to claim 1 but are separately focused on ventricular fibrillation and ventricular arrhythmias. The additional claims increase claim-count coverage but do not introduce composition or manufacturing protection. Is RE29618 a composition patent or a method-of-use patent?RE29618 is a method-of-use patent. It does not protect:
The patent could historically have been asserted against a manufacturer or provider whose product labeling, promotional activity, or clinical use encouraged the claimed cardiac indications. It would not have provided the same product-level protection as a compound patent or formulation patent. When did RE29618 lose exclusivity?RE29618 has no surviving U.S. patent term. The patent is decades past expiration. For a pre-1995 U.S. patent, the applicable term was generally 17 years from the original patent grant, subject to the statutory rules then in effect. A reissue patent does not restart the patent term or extend protection beyond the term of the original patent. The relevant expiration analysis therefore requires examination of the original patent from which RE29618 issued, rather than treating the reissue grant date as a new 17-year term. [1]
The expired status eliminates current infringement risk under RE29618. It also means that an ANDA applicant does not need to file a Paragraph IV certification against this patent unless the patent appears in a currently relevant Orange Book listing, which would be highly unlikely for an expired historical method patent. What is the Orange Book status of bretylium tosylate?The FDA Orange Book is relevant only to patents associated with an approved drug product and listed by the NDA holder in accordance with FDA regulations. Orange Book listing does not revive an expired patent and does not create exclusivity after patent expiration. [2] Bretylium tosylate is an established active pharmaceutical ingredient with historical use as an antiarrhythmic injection. The product has been marketed in the United States under various commercial and generic arrangements, including injectable products. RE29618 is not a current source of Orange Book exclusivity. The regulatory issues for a new applicant would be separate from the patent issue. Depending on the regulatory pathway and the status of the reference product, an applicant could need to address:
An expired method-of-use patent does not prevent FDA approval of a generic or follow-on bretylium tosylate product. Are there formulation patents covering bretylium tosylate?RE29618 does not contain meaningful formulation protection. Claims 3 and 4 require administration in an aqueous solution, but that limitation describes the route and dosage form used in the claimed treatment method. It does not claim a formulation with defined excipients, pH, concentration, stability profile, or container. A later formulation patent could theoretically cover a specific injectable composition, but such a patent would need to be analyzed separately. The existence of RE29618 does not establish that any formulation patent exists or remains enforceable. For commercial diligence, the relevant formulation questions are:
Does RE29618 create Paragraph IV risk?No current Paragraph IV risk arises from an expired patent. Paragraph IV certification applies when an ANDA applicant asserts that a listed patent is invalid, unenforceable, or will not be infringed. A patent that has expired cannot block approval based on remaining patent term. The FDA’s ANDA patent-certification framework is governed by the Hatch-Waxman statute and implementing regulations. [3] Historically, a listed method-of-use patent could have generated a Paragraph IV dispute if it covered an indication included in the proposed labeling. That issue is no longer commercially material for RE29618. A current applicant should still review:
Those potential rights would arise from later regulatory or patent records, not from RE29618. What patent litigation and settlements affect RE29618?No current litigation or settlement agreement can preserve exclusivity after RE29618’s patent term has expired. Any historical enforcement action, ANDA dispute, or licensing arrangement involving the patent would have ended as a practical barrier once the patent expired. A settlement cannot extend the statutory patent term. It can allocate launch dates or impose contractual restrictions among private parties during the term, but those restrictions do not create a patent right against unrelated companies after expiration. The claim structure suggests that any historical dispute would likely have focused on:
How strong was the RE29618 patent estate?The estate was narrow in product coverage and relatively broad in therapeutic-use language.
Claim 1 had the broadest historical reach because it did not require a specific route, dose, formulation, or disease subtype beyond ventricular fibrillation or ventricular arrhythmias. Claims 2 through 5 were easier to analyze but narrower because they added dose, route, emergency-condition, procedural, or oral-regimen limitations. The central vulnerability of the claim set was that it depended on a known active ingredient and a therapeutic-use concept rather than controlling the underlying molecule or product. Once the patent expired, competitors could manufacture and market bretylium tosylate subject to FDA, quality, supply-chain, and applicable non-patent requirements. What generic launch risks exist for bretylium tosylate?The principal launch risks are regulatory and commercial rather than patent-based. Regulatory riskBretylium tosylate is an older injectable antiarrhythmic. A sponsor would need to establish a viable FDA regulatory pathway, product quality, sterility, and clinical or bioequivalence support appropriate to the reference product and application type. Manufacturing riskPotential barriers include:
These barriers are practical IP-adjacent constraints, but they are not claimed by RE29618. Commercial riskBretylium tosylate has a narrow emergency-care market. Demand may be affected by:
A patent-free market does not necessarily produce an attractive generic opportunity when the addressable volume is low and sterile manufacturing costs are high. How does RE29618 compare with other possible bretylium patents?
The patent landscape for a current bretylium tosylate project should therefore distinguish historical use patents from any later patents covering commercial formulations, manufacturing processes, or regulatory exclusivities. RE29618 alone does not support a blocking-rights position. What is the geographic scope of RE29618?The patent is a United States right. It has no direct effect in Canada, Europe, Japan, China, or other jurisdictions. Foreign counterparts would require separate analysis of:
Because the active ingredient and clinical use are old, foreign counterparts are also likely to be expired, but that conclusion must be established from each national register rather than inferred solely from the U.S. reissue. Key Takeaways
FAQs About Bretylium Tosylate Patent RightsCan a generic company market bretylium tosylate without licensing RE29618?Yes. RE29618 is expired, so it does not require a current patent license. Does claim 3 cover every IV bretylium tosylate injection?No. Claim 3 requires the specified emergency clinical circumstances, dose range, aqueous IV administration, vigorous massage, and resistance to electrical defibrillation. Does RE29618 cover oral bretylium tosylate tablets?Claim 5 covers a method using oral bretylium tosylate at specified dosing intervals. It does not claim tablets or a particular tablet formulation. Can an expired bretylium patent remain listed in the Orange Book?An expired patent may remain visible in historical records, but expiration eliminates its ability to block approval or marketing based on remaining patent term. Are bretylium tosylate biosimilar rules applicable?No. Bretylium tosylate is a chemically synthesized small-molecule drug, not a biologic. The biosimilar pathway under Section 351(k) of the Public Health Service Act does not apply. References
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Drugs Protected by US Patent RE29618
| Applicant | Tradename | Generic Name | Dosage | NDA | Approval Date | TE | Type | RLD | RS | Patent No. | Patent Expiration | Product | Substance | Delist Req. | Patented / Exclusive Use | Submissiondate |
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| >Applicant | >Tradename | >Generic Name | >Dosage | >NDA | >Approval Date | >TE | >Type | >RLD | >RS | >Patent No. | >Patent Expiration | >Product | >Substance | >Delist Req. | >Patented / Exclusive Use | >Submissiondate |
