US Patent 11,918,623: Tirzepatide Obesity- treatment Claims, Patent Scope, and Competitive Landscape
US Patent 11,918,623 protects methods of treating obesity with tirzepatide formulations containing defined concentrations of sodium chloride and dibasic sodium phosphate. The strongest commercial claim is claim 15, which maps closely to the labeled single-dose injectable formulation of Zepbound and Mounjaro. The patent is a formulation-use patent, not a basic-molecule patent. Its practical value depends on Orange Book listing status, patent-term data, formulation equivalence, and whether a competing product is marketed for obesity using an automatic injector.
What does US Patent 11,918,623 protect?
US 11,918,623 protects administering a tirzepatide pharmaceutical composition to treat obesity when the composition contains specified excipients and concentration ranges.[1]
The independent claims are:
| Claim |
Protected subject matter |
Principal limitation |
| 1 |
Obesity treatment method |
Tirzepatide at about 5-30 mg/mL; dibasic sodium phosphate at about 0.67-2.68 mg/mL; NaCl at about 6.2-9.5 mg/mL; optional phenol |
| 4 |
Obesity treatment method |
Tirzepatide, NaCl at about 6.2-9.5 mg/mL, and dibasic sodium phosphate |
| 15 |
Obesity treatment method |
Tirzepatide at about 5-30 mg/mL; dibasic sodium phosphate at about 1.34 mg/mL; NaCl at about 8.2 mg/mL; automatic injector |
Claims 2 and 3 narrow claim 1 by requiring an automatic injection apparatus and once-weekly administration. Claims 5 through 11 narrow claim 4 by adding tirzepatide and excipient concentrations. Claims 12 through 14 narrow claim 1 by specifying commercial tirzepatide concentrations and sodium chloride levels.
The claims do not require phenol except where the limitation is included through claim 1. Claim 4 and its dependent claims do not expressly require phenol. Claim 15 also does not expressly require phenol.
How broad are the independent claims?
Claim 4 is the broadest composition-use claim. It does not specify a tirzepatide concentration and requires only:
- Tirzepatide or a pharmaceutically acceptable salt;
- Sodium chloride at about 6.2-9.5 mg/mL; and
- Dibasic sodium phosphate.
That structure creates a wider literal claim scope than claim 1, which adds the 5-30 mg/mL tirzepatide range and optional phenol range. A competing formulation could fall within claim 4 even if its tirzepatide concentration is outside 5-30 mg/mL, provided the product is used to treat obesity and satisfies the sodium chloride and phosphate limitations.
Claim 15 is narrower in formulation scope but commercially important. It requires the concentration values approximately corresponding to the marketed tirzepatide injection:
- Tirzepatide: 5-30 mg/mL;
- Dibasic sodium phosphate: about 1.34 mg/mL;
- Sodium chloride: about 8.2 mg/mL; and
- Automatic injection apparatus.
The claim does not require once-weekly dosing. A once-weekly regimen is required by claim 3, but not by claim 15.
Which commercial tirzepatide concentrations fall within the claims?
The marketed dose strengths correspond to the following concentration profile when delivered in a 0.5 mL injection volume:
| Labeled dose |
Approximate tirzepatide concentration |
| 2.5 mg |
5 mg/mL |
| 5 mg |
10 mg/mL |
| 7.5 mg |
15 mg/mL |
| 10 mg |
20 mg/mL |
| 12.5 mg |
25 mg/mL |
| 15 mg |
30 mg/mL |
All six concentrations are expressly listed in claims 9 and 12. The labeled concentrations of sodium chloride and dibasic sodium phosphate are also consistent with the narrow limitations in claims 8 and 11 and claim 15.[2][3]
This alignment gives claim 15 direct relevance to commercial single-dose tirzepatide injector products. The claim is less dependent on the precise tirzepatide dose because it covers the entire 5-30 mg/mL range.
What formulations are protected by US 11,918,623?
The patent covers formulations using sodium chloride as a tonicity agent and dibasic sodium phosphate as a buffering component. The key numerical ranges are:
| Component |
Broad claimed range |
Narrow claimed value or range |
| Tirzepatide |
About 5-30 mg/mL |
5, 10, 15, 20, 25, or 30 mg/mL |
| Dibasic sodium phosphate |
About 0.67-2.68 mg/mL |
About 1.34 mg/mL |
| Sodium chloride |
About 6.2-9.5 mg/mL |
About 7.0-9.0 mg/mL; about 8.2 mg/mL |
| Phenol |
About 3.0-7.0 mg/mL |
Optional under claim 1 |
The claims are concentration-based. A formulation assessment therefore requires analysis of the actual concentration in the finished dosage form, not merely the amount per syringe or vial.
For a 0.5 mL dose, the claimed concentrations correspond approximately to:
| Component |
Concentration |
Amount per 0.5 mL dose |
| Sodium chloride |
8.2 mg/mL |
4.1 mg |
| Dibasic sodium phosphate |
1.34 mg/mL |
0.67 mg |
| Phenol |
5 mg/mL |
2.5 mg |
The patent uses “about,” which introduces a claim-construction issue. The permissible variation depends on the intrinsic evidence, specification examples, prosecution history, measurement conventions, and the ordinary meaning applied by a court. A product narrowly outside a numerical range may still face an equivalents analysis, but numerical-range claims often produce fact-specific disputes over criticality and prosecution estoppel.
How does US 11,918,623 relate to Zepbound and Mounjaro?
Zepbound is tirzepatide approved by the FDA for chronic weight management in adults with obesity or overweight and at least one weight-related condition.[2] Mounjaro is tirzepatide approved for glycemic control in adults with type 2 diabetes.[3]
The patent claims are expressly directed to treating obesity. That makes Zepbound the principal marketed product exposed to the claims. Mounjaro may have overlapping formulation characteristics, but the claimed method requires the obesity-treatment indication. A product used solely according to an approved diabetes indication would present a different infringement analysis from a product promoted, prescribed, or labeled for obesity.
| Product |
Active ingredient |
FDA indication relevant to these claims |
Formulation overlap |
| Zepbound |
Tirzepatide |
Chronic weight management |
Direct |
| Mounjaro |
Tirzepatide |
Type 2 diabetes |
Formulation overlap; obesity-use issue |
| Wegovy |
Semaglutide |
Chronic weight management |
No tirzepatide; outside literal composition scope |
| Saxenda |
Liraglutide |
Chronic weight management |
No tirzepatide; outside literal composition scope |
The patent does not cover semaglutide, liraglutide, or other non-tirzepatide GLP-1 products.
When does US Patent 11,918,623 lose exclusivity?
The patent issued on March 5, 2024.[1] Its enforceable term is determined under the patent-term rules from the applicable nonprovisional or PCT filing date, adjusted for patent-term adjustment and potentially affected by terminal disclaimers. The grant date alone does not establish the expiration date.
The patent’s effective expiration must be confirmed from the USPTO Patent Center record and the patent-term adjustment calculation. If the patent is part of a continuation family or subject to a terminal disclaimer, the expiration date may be tied to an earlier related patent rather than calculated independently from its own filing date.
The commercial exclusivity analysis should separate:
- FDA regulatory exclusivity;
- Patent term;
- Orange Book listing;
- Approved-label scope;
- Paragraph IV certifications;
- Settlement restrictions; and
- Possible pediatric or patent-term extensions.
Zepbound received FDA approval in November 2023. Its regulatory exclusivity and listed-patent profile are separate from the March 2024 grant of US 11,918,623.[2]
What is the Orange Book status of US 11,918,623?
The claims are method-of-use claims and may be eligible for Orange Book listing if the patent is submitted by the NDA holder and FDA accepts that it claims an approved method of using the drug.[4]
An Orange Book listing would materially affect generic competition because an ANDA applicant would ordinarily need to address the listed patent through a Paragraph I, II, III, or IV certification. A Paragraph IV certification alleges that the patent is invalid, unenforceable, or not infringed.
The patent claims obesity treatment rather than a general tirzepatide formulation. Its listing value therefore depends on the Zepbound NDA and the FDA-approved obesity indication. Listing against Mounjaro would raise a separate indication and product-specific question.
The patent itself does not establish:
- Whether FDA has accepted it for Orange Book listing;
- Which NDA or NDAs contain the listing;
- Whether the listing has been withdrawn;
- Whether an ANDA applicant has submitted a Paragraph IV certification; or
- Whether litigation has triggered a 30-month stay.
Those facts must be taken from the current FDA Orange Book and FDA patent-listing records, not inferred from the claims.[4]
Which companies are challenging tirzepatide patent protection?
The claims supplied do not identify any Paragraph IV challenger, ANDA filing, litigation complaint, or settlement agreement. A complete current challenger analysis cannot be derived from the patent claims.
Potential generic entry would require a product meeting the applicable ANDA requirements and a certification against each relevant Orange Book patent. A non-infringing formulation could attempt to avoid the concentration limitations. A Paragraph IV strategy could challenge:
- Lack of written description;
- Lack of enablement;
- Obviousness over tirzepatide formulations and conventional injectable excipients;
- Indefiniteness of “about”;
- Lack of infringement based on concentration or apparatus;
- Lack of induced infringement based on the approved label; or
- Enforceability issues arising from prosecution conduct.
The patent’s formulation claims are more vulnerable to design-around than claims directed to the tirzepatide molecule itself. A competitor could target changes in buffer, tonicity agent, concentration, preservative, delivery device, or indication wording. Claim 4 limits some design-around options because it does not require a specific tirzepatide concentration, but it still requires the claimed sodium chloride range and dibasic sodium phosphate.
How strong is the patent estate for tirzepatide?
US 11,918,623 is one component of a broader tirzepatide patent estate. The main estate categories are:
| Patent category |
Commercial purpose |
Relevance to US 11,918,623 |
| Composition-of-matter patents |
Protect tirzepatide itself |
Separate and potentially stronger blocking rights |
| Formulation patents |
Protect excipients, concentrations, stability, and dosage forms |
Directly related |
| Method-of-use patents |
Protect obesity, diabetes, cardiovascular, or dosing methods |
Directly related to claims 1-15 |
| Device patents |
Protect autoinjectors, pens, cartridges, and delivery systems |
Claim 2, 3, and 15 overlap functionally |
| Manufacturing patents |
Protect peptide synthesis, purification, and formulation processes |
Can create supply-chain barriers |
| Data and regulatory exclusivity |
Delay abbreviated approval |
Operates independently of patent claims |
The patent is strongest against a product that reproduces the commercial formulation, uses an automatic injector, and is labeled or promoted for obesity. It is weaker against:
- A non-injectable formulation;
- A formulation using a different buffer system;
- A product outside the sodium chloride range;
- A product that omits dibasic sodium phosphate;
- A product approved only for a non-obesity indication; or
- A product that avoids the automatic-injector limitation where relying on claims 2, 3, or 15.
Claims 1 and 4 provide broader protection than claim 15 because they do not require every commercial device limitation. Claim 15, however, is factually easier to map to a commercial autoinjector product.
What generic launch risks exist?
A generic tirzepatide launch could follow three principal paths.
Paragraph III launch
The applicant accepts the listed patent and delays launch until the patent expires. This reduces litigation risk but postpones market entry.
Paragraph IV launch
The applicant challenges validity, enforceability, or infringement. If the NDA holder sues within the statutory period, FDA approval may be subject to a 30-month stay, subject to statutory exceptions and court developments.[5]
Non-infringing formulation launch
The applicant designs around the claimed concentrations or excipients. This approach avoids a direct patent challenge but creates formulation-development, stability, bioequivalence, device, and regulatory risks.
For a tirzepatide product intended for obesity, the highest-risk design is a ready-to-use injectable formulation with 5-30 mg/mL tirzepatide, approximately 8.2 mg/mL sodium chloride, approximately 1.34 mg/mL dibasic sodium phosphate, and an automatic injector. That combination tracks claim 15 and multiple dependent claims.
Does the patent create biosimilar risk?
No conventional biosimilar pathway applies because tirzepatide is a synthetic peptide drug rather than a biological product approved under the Public Health Service Act biosimilar framework. A follow-on tirzepatide product would generally pursue an ANDA or another applicable abbreviated or full NDA pathway, depending on FDA classification and product characteristics.
The relevant competitive risk is therefore generic or follow-on tirzepatide competition, not biosimilar substitution. Device differences and formulation differences may also affect substitutability and pharmacy-level interchangeability.
What is the litigation and settlement status?
The claim set alone does not identify litigation, a court decision, a Paragraph IV notice, or a settlement. No litigation or settlement conclusion should be inferred solely from issuance of the patent.
A diligence review should treat the following as separate records:
- USPTO Patent Center prosecution history;
- FDA Orange Book listing data;
- District-court complaints and docket entries;
- Federal Circuit decisions;
- ANDA litigation notices;
- FDA approval letters; and
- Public settlement filings or antitrust disclosures.
Key Takeaways
- US 11,918,623 is a tirzepatide formulation-use patent directed to obesity treatment.
- Claim 4 is the broadest independent claim because it does not specify a tirzepatide concentration.
- Claim 15 closely tracks the commercial injectable formulation and automatic-injector presentation.
- The six commercial concentrations from 5 to 30 mg/mL fall within the express concentration limitations.
- Zepbound is the primary marketed product implicated by the obesity-treatment claims.
- Mounjaro has formulation overlap, but its approved diabetes indication creates a separate method-of-use analysis.
- The claims do not protect semaglutide, liraglutide, or other non-tirzepatide GLP-1 products.
- The patent is vulnerable to design-around through changes to excipients, concentration ranges, delivery devices, or indication strategy.
- Current Orange Book status, Paragraph IV activity, litigation, settlement agreements, and the exact expiration date cannot be established from the claim text alone.
- A commercial freedom-to-operate analysis must review the full tirzepatide patent family, not US 11,918,623 in isolation.
FAQs About US Patent 11,918,623
Does US 11,918,623 cover tirzepatide itself?
No. The supplied claims cover methods of treating obesity with specified tirzepatide formulations. They do not claim the tirzepatide molecule as a composition of matter.
Does the patent cover once-weekly Zepbound dosing?
Claims 2 and 3 expressly include automatic injection and once-weekly dosing. Claim 15 requires an automatic injector but does not expressly require once-weekly administration.
Can a tirzepatide product avoid the patent by omitting phenol?
Possibly. Phenol is optional in claim 1 and is not expressly required by claim 4 or claim 15. Omitting phenol alone would not avoid the claims if all other limitations are met.
Is a vial product outside claim 15?
A vial would likely avoid claim 15’s automatic-injection limitation, but it could remain exposed to claims 1, 4, and other claims if the formulation and obesity-treatment limitations are satisfied.
Does US 11,918,623 block all generic tirzepatide products?
No. Its scope is limited by the claimed formulation components, concentrations, obesity-treatment use, and, for certain claims, automatic-injector or weekly-dosing requirements.
References
- United States Patent and Trademark Office. (2024). U.S. Patent No. 11,918,623, pharmaceutical compositions comprising tirzepatide.
- U.S. Food and Drug Administration. (2023). Zepbound prescribing information. Eli Lilly and Company.
- U.S. Food and Drug Administration. (2022). Mounjaro prescribing information. Eli Lilly and Company.
- U.S. Food and Drug Administration. (n.d.). Approved drug products with therapeutic equivalence evaluations: Orange Book.
- U.S. Food and Drug Administration. (n.d.). Abbreviated new drug application patents and exclusivity provisions.
