US Patent 10,183,020: Osimertinib Formulation Claims, Expiration, Orange Book Status and Generic Risk
US Patent 10,183,020 protects specific oral solid formulations of osimertinib mesylate, the active ingredient in AstraZeneca’s Tagrisso. The patent does not broadly claim osimertinib as a molecule. Its coverage is directed to excipient ratios, microcrystalline cellulose content, tablet compositions, coated tablets and oral treatment methods, including treatment of non-small cell lung cancer.
The patent’s principal commercial relevance is its potential to delay or complicate generic osimertinib tablet entry after the core compound and method-of-use patents expire. Public patent records identify AstraZeneca as the patent owner, with an estimated expiration date of March 31, 2035, subject to the official term calculation and any applicable patent-term adjustments.[1]
What drug does US Patent 10,183,020 protect?
The claimed active ingredient is osimertinib mesylate, chemically identified as:
N-(2-{2-dimethylaminoethyl-methylamino}-4-methoxy-5-{[4-(1-methylindol-3-yl)pyrimidin-2-yl]amino}phenyl)prop-2-enamide mesylate.
Osimertinib is a third-generation, irreversible epidermal growth factor receptor tyrosine kinase inhibitor. AstraZeneca markets it in the United States as Tagrisso tablets for EGFR-mutated non-small cell lung cancer.[2]
The patent protects the dosage-form architecture rather than the pharmacological mechanism. Its claims require a combination of:
- Osimertinib mesylate.
- At least two pharmaceutical diluents.
- Microcrystalline cellulose as one diluent.
- Microcrystalline cellulose representing 7% to 30% by weight of the total diluent fraction.
- One or more disintegrants.
- Optional solubilizing agents.
- One or more lubricants.
- Tablet or coated-tablet embodiments in several claims.
What are the core claims of US 10,183,020?
Claim 1 is the broadest independent composition claim. It requires the following weight-part ranges:
| Component |
Claimed range |
| Osimertinib mesylate |
2 to 70 parts |
| Two or more diluents |
5 to 96 parts |
| Disintegrant |
2 to 15 parts |
| Solubilizing agent |
0 to 0.75 parts |
| Lubricant |
0 to 3 parts |
| Total |
100 parts |
The formulation must contain microcrystalline cellulose, and that cellulose must constitute 7% to 30% of the total diluent component.
The claim is therefore narrower than a claim covering every osimertinib tablet. A competing product could attempt to avoid infringement by using a single diluent, omitting microcrystalline cellulose, placing microcrystalline cellulose outside the required relative range, or using a different dosage form. Those design-arounds would depend on the complete formulation and the construction of the claim language.
How do the dependent claims narrow the patent scope?
The dependent claims create progressively narrower formulation positions.
| Claims |
Added limitation |
| 2 |
Lubricant at 1 to 2.5 parts |
| 3 |
Sodium stearyl fumarate or glycerine behenate ester lubricant |
| 4 |
Disintegrant at 2 to 10 parts |
| 5 |
Low-substituted hydroxypropyl cellulose disintegrant |
| 6 |
Solubilizer at 0 to 0.25 parts |
| 7 |
Osimertinib mesylate at 5 to 50 parts |
| 14 |
No solubilizing agent |
| 15 |
Osimertinib mesylate at 7 to 30 parts |
| 16 |
Specific classes of additional diluents, low-substituted hydroxypropyl cellulose, and specified lubricants |
| 21 |
Two diluents, no solubilizer, 7 to 25 parts active, 55 to 85 parts diluents |
| 22 |
Microcrystalline cellulose and mannitol; low-substituted hydroxypropyl cellulose; sodium stearyl fumarate |
| 23 |
Approximately 19 parts active, 59 parts mannitol, 15 parts microcrystalline cellulose, 5 parts disintegrant and 2 parts sodium stearyl fumarate |
Claim 23 is the most commercially specific formulation claim. It corresponds to a tablet composition containing approximately:
- 19% osimertinib mesylate.
- 59% mannitol.
- 15% microcrystalline cellulose.
- 5% low-substituted hydroxypropyl cellulose.
- 2% sodium stearyl fumarate.
The listed amounts total approximately 100 parts. The word “about” introduces potential claim-construction issues, particularly concerning the permitted numerical variation around each amount.
What formulations are protected by US 10,183,020?
The strongest practical coverage is directed to immediate-release oral tablets using mannitol and microcrystalline cellulose as the two diluents, low-substituted hydroxypropyl cellulose as disintegrant and sodium stearyl fumarate as lubricant.
The claim hierarchy covers three levels of formulation risk:
- Broad excipient architecture under claim 1.
- Defined excipient classes and ranges under claims 16 and 21.
- A commercially representative composition under claims 22 and 23.
The patent does not require every formulation to use mannitol. Claim 1 allows numerous diluents, including lactose, starch, sorbitol, sucrose, xylitol, erythritol, isomalt, maltitol and polyethylene glycol. Claim 16 lists an extensive set of permitted non-cellulose diluents.
A generic manufacturer using mannitol, microcrystalline cellulose, low-substituted hydroxypropyl cellulose and sodium stearyl fumarate may face a substantial literal-infringement risk if its quantitative ratios fall within the claims.
Do the claims cover tablets and cancer treatment methods?
Yes. Claims 9, 10, 18 and 19 cover pharmaceutical tablets and coated tablets containing the claimed composition. Claims 8, 11, 17 and 20 cover oral administration of the composition or tablets to treat cancer.
Claims 12 and 13 narrow the treatment indication to non-small cell lung cancer. Claims 17 and 20 depend on claim 16 and therefore carry the more detailed formulation limitations associated with the mannitol and microcrystalline-cellulose embodiments.
The method claims may be less important than the composition claims in an ANDA dispute. Generic applicants generally seek approval for a drug product and may use a Paragraph IV certification against listed formulation patents. A method claim can still matter if the proposed labeling directs use in a way that practices the claimed treatment method.
What is the Orange Book status of US Patent 10,183,020?
US Patent 10,183,020 has been associated with Tagrisso’s FDA-listed patent estate as a formulation patent. The Orange Book listing is commercially significant because an ANDA applicant must address listed patents through a Paragraph III certification, Paragraph IV certification, or other applicable certification.[3]
| Regulatory item |
Status |
| Drug |
Tagrisso |
| Active ingredient |
Osimertinib mesylate |
| Dosage form |
Oral tablet |
| NDA holder |
AstraZeneca Pharmaceuticals LP |
| Patent type |
Formulation and tablet composition |
| Orange Book relevance |
Listed patent barrier for ANDA applicants |
| Estimated patent expiry |
March 31, 2035 |
| FDA approval pathway |
New drug application; initially accelerated approval |
A Paragraph IV notice alleging invalidity, unenforceability or non-infringement can trigger patent litigation. If the NDA holder files suit within the statutory period, FDA approval of the ANDA may be stayed for up to 30 months, subject to statutory exceptions and court action.[4]
When does osimertinib lose exclusivity?
Osimertinib has multiple exclusivity layers.
| Exclusivity layer |
Approximate end point |
| Core compound patent, US 8,969,393 |
March 23, 2032 |
| Formulation patent, US 10,183,020 |
March 31, 2035 |
| New chemical entity exclusivity |
November 2020 |
| Regulatory exclusivity after NCE period |
Patent-dependent |
| Biosimilar exclusivity |
Not applicable |
The March 2035 date is the important formulation-patent date. It is later than the principal compound patent date because US 10,183,020 belongs to a later patent family and received a different term calculation.[1]
The 2035 date does not necessarily mean that no generic osimertinib product can enter before then. Earlier entry could occur through a successful invalidity or non-infringement challenge, a settlement agreement, a license, a product design-around, or a court order limiting the patent’s enforceability.
Which companies are challenging the Tagrisso patent estate?
The relevant challengers are manufacturers that submit ANDAs for osimertinib tablets and provide Paragraph IV certifications against listed Tagrisso patents. Publicly disclosed generic activity has involved major ANDA applicants, including Teva, Sun Pharmaceutical, Lupin, Apotex and Zydus entities in different patent and regulatory contexts.
The exact litigation exposure must be assessed patent by patent. A Paragraph IV challenge to the compound patent does not automatically challenge US 10,183,020. Conversely, a generic applicant can avoid a formulation patent by certifying that its product does not infringe while separately litigating the compound or method patents.
The critical diligence questions are:
- Whether an ANDA applicant has certified Paragraph IV against US 10,183,020.
- Whether AstraZeneca filed an infringement action within 45 days.
- Whether a 30-month stay applies.
- Whether the applicant’s formulation falls within claims 1, 16, 21, 22 or 23.
- Whether the parties entered a licensed-entry settlement.
- Whether the product label includes uses implicated by claims 8, 11, 12, 13, 17 or 20.
How strong is the patent estate for US 10,183,020?
The patent has moderate-to-strong commercial value but narrower technical breadth than a compound patent.
Strengths
- Claim 1 covers a broad range of active-ingredient and excipient proportions.
- The microcrystalline-cellulose requirement creates a defined formulation fingerprint.
- Claims 21 to 23 provide fallback positions with increasingly specific excipient combinations.
- The patent covers compositions, tablets and oral treatment methods.
- The formulation appears aligned with the marketed tablet architecture.
Vulnerabilities
- Many claimed excipients are conventional pharmaceutical ingredients.
- Prior-art formulations could be used in an obviousness challenge.
- The patent’s enforceability depends on proving that the claimed ratios provide a non-obvious technical result.
- A generic manufacturer may design around the microcrystalline-cellulose percentage or substitute excipients.
- Claim 23’s “about” language may generate disputes over numerical tolerance.
- The patent does not independently protect the chemical identity of osimertinib.
The strongest litigation position would likely rely on claims 22 and 23 if the accused product closely tracks the commercial formulation. Claims 1 and 16 provide broader coverage but may face greater prior-art and obviousness pressure.
What manufacturing and intellectual-property barriers affect generic entry?
The formulation patent is one barrier within a larger product-specific estate. Generic entrants must also address:
- The active pharmaceutical ingredient and salt form.
- Crystalline or solid-state properties.
- Tablet manufacturing process.
- Dissolution and bioequivalence requirements.
- Stability and impurity controls.
- Orange Book method-of-use patents.
- Regulatory exclusivity and labeling restrictions.
- Potential confidential know-how relating to scale-up and tableting.
A formulation design-around may avoid US 10,183,020 but still create bioequivalence or manufacturability problems. The practical barrier is therefore a combination of patent scope, formulation performance and FDA approval requirements.
How does Tagrisso compare with competing EGFR therapies?
| Product |
Active ingredient |
Main commercial position |
Biosimilar risk |
| Tagrisso |
Osimertinib |
EGFR-mutated NSCLC, including adjuvant and metastatic settings |
None; small molecule |
| Alecensa |
Alectinib |
ALK-positive NSCLC |
None |
| Gilotrif |
Afatinib |
EGFR-mutated NSCLC |
None |
| Iressa |
Gefitinib |
EGFR-mutated NSCLC |
Generic risk |
| Lazcluze |
Lazertinib |
EGFR-mutated NSCLC, used with amivantamab |
None |
| Aumolertinib |
Aumolertinib |
EGFR-mutated NSCLC in selected markets |
None |
Tagrisso’s main competitive advantage is its broad clinical positioning across earlier-stage and advanced EGFR-mutated disease. Its revenue exposure is material. AstraZeneca reported approximately $5.8 billion in 2023 Tagrisso sales, making formulation and patent protection commercially significant.[5]
Key Takeaways
- US 10,183,020 is an osimertinib mesylate formulation patent, not a basic compound patent.
- Its central limitation is microcrystalline cellulose comprising 7% to 30% of the total diluent fraction.
- Claims 22 and 23 focus on mannitol, microcrystalline cellulose, low-substituted hydroxypropyl cellulose and sodium stearyl fumarate.
- The patent covers compositions, tablets, coated tablets and oral cancer-treatment methods.
- Its estimated expiration date is March 31, 2035.
- Generic risk depends on formulation analysis, Paragraph IV certifications, litigation and potential design-arounds.
- No biosimilar pathway applies because osimertinib is a small-molecule drug.
- The patent has meaningful commercial value but is more vulnerable to formulation prior art than a compound patent.
FAQs About US Patent 10,183,020
Can a generic use a different lubricant and avoid US 10,183,020?
Possibly. Claims 3, 16 and 22 specifically identify sodium stearyl fumarate and certain behenate esters, but claim 1 is broader. The complete formulation must be compared with every limitation of the asserted claim.
Does US 10,183,020 cover Tagrisso’s active ingredient by itself?
No. The patent requires osimertinib mesylate in a pharmaceutical composition with specified excipients and quantitative relationships.
Can a generic launch before March 31, 2035?
Yes, if it obtains a license, prevails in litigation, establishes non-infringement, invalidates the patent, reaches a settlement with an agreed entry date or uses a formulation outside the asserted claims.
Is US 10,183,020 a method-of-use patent?
It includes method-of-treatment claims, but its principal protection is directed to pharmaceutical compositions and tablets. The treatment claims cover oral administration, including treatment of non-small cell lung cancer.
Does the patent block all non-U.S. osimertinib products?
No. US 10,183,020 has territorial effect in the United States. Separate national patents and applications determine protection in Europe, Japan, China and other jurisdictions.
References
[1] United States Patent and Trademark Office. (2019). US Patent No. 10,183,020, Pharmaceutical composition. U.S. Department of Commerce.
[2] U.S. Food and Drug Administration. (2024). Tagrisso (osimertinib) prescribing information. FDA.
[3] U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations: Orange Book. FDA.
[4] United States Code. (2024). 21 U.S.C. § 355(j): Abbreviated applications for new drugs.
[5] AstraZeneca PLC. (2024). Annual report and Form 20-F 2023. AstraZeneca.
