US Patent 7,786,118: Temozolomide Formulation Claims, Expiration, and Patent Landscape

US Patent 7,786,118 is a formulation patent directed to aqueous temozolomide compositions stabilized with L-threonine. Its broadest claim requires only three components: temozolomide or a pharmaceutically acceptable salt, an aqueous diluent, and L-threonine. Dependent claims narrow the formulation through hydrochloric acid, citrate buffer, polysorbate, mannitol, defined weight ranges, and pH.

The patent is materially narrower than a patent covering temozolomide itself. It does not cover every temozolomide product, capsule, tablet, oral dosage form, or method of treating cancer. Its commercial significance depends on whether a competing product is an aqueous formulation containing L-threonine and whether the formulation falls within the dependent-claim limitations.

The patent’s projected 20-year term appears to run from a 2004 priority date, placing ordinary expiration in December 2025, subject to any patent-term adjustment or other term calculation reflected in the USPTO record. The claims raise potential indefiniteness and enablement issues because the stated weight percentages in claims 4 and 5 exceed 100% when read as percentages of the complete formulation.

What does US Patent 7,786,118 cover?

US Patent 7,786,118 covers pharmaceutical formulations of temozolomide in an aqueous environment that contain L-threonine. The patent is directed to formulation chemistry rather than temozolomide’s antineoplastic mechanism or any particular cancer treatment method.

Claim	Principal limitation	Practical scope
1	Temozolomide or salt, aqueous diluent, L-threonine	Broadest claim; captures the basic aqueous/L-threonine combination
2	Claim 1 plus hydrochloric acid, citrate buffer, polysorbate, and mannitol	Narrow multi-excipient formulation
3	Claim 2 plus an aqueous diluent	Redundant on its face because claim 1 already requires an aqueous diluent
4	Claim 2 plus specified weight ranges	Narrow quantitative formulation claim
5	Claim 2 plus approximate component concentrations	Narrower composition centered on a stated formulation
6	Claim 5 plus pH of about 3.0 to 4.5	Narrowest expressly claimed formulation

The independent claim does not require the formulation to be injectable, lyophilized, reconstituted, ready-to-use, oral, or parenteral. Claim construction would determine whether the claimed “pharmaceutical formulation” encompasses a concentrate, a reconstituted solution, an intermediate, or a finished dosage form.

How broad is claim 1 of US 7,786,118?

Claim 1 is the principal infringement risk because it contains no concentration, pH, excipient-ratio, route-of-administration, or dosage-form limitation.

A formulation may fall within claim 1 if it contains:

Temozolomide or a pharmaceutically acceptable salt;
At least one aqueous diluent; and
L-threonine.

The claim does not require the presence of hydrochloric acid, citrate, polysorbate, or mannitol. A competitor could therefore infringe claim 1 with a formulation using a different buffer system or stabilizer if L-threonine remains present.

The phrase “at least one aqueous diluent” is expansive. Water, buffered aqueous media, and other water-containing pharmaceutical vehicles could potentially satisfy this limitation. The claim also does not state a minimum amount of L-threonine. A low concentration may still satisfy the claim unless the specification or prosecution history imposes a limiting construction.

Claim 1 does not cover a dry temozolomide composition lacking an aqueous diluent. It also does not cover an aqueous formulation that uses a different amino acid instead of L-threonine, unless the accused product contains L-threonine as an additional component.

What formulations are protected by claims 2 through 6?

Claims 2 through 6 progressively narrow the formulation by adding excipients and quantitative limitations.

Claim 2: Defined excipient combination

Claim 2 requires the claim 1 formulation plus:

Hydrochloric acid;
A citrate buffer;
A polysorbate; and
Mannitol.

The claim does not specify concentrations, polysorbate grade, citrate species, mannitol form, or the particular hydrochloric-acid concentration. A formulation containing polysorbate 80, for example, could potentially fall within the claim if the other limitations are met.

The claim’s use of “a citrate buffer” creates a chemical limitation but may permit multiple citrate systems, including citric acid/citrate combinations. Whether a formulation contains a true citrate buffer depends on pH, acid-base composition, and claim construction.

Claim 3: Redundant aqueous-diluent limitation

Claim 3 adds “an aqueous dilutent” to claim 2. Claim 1 already requires an aqueous diluent, and claim 2 depends on claim 1. As drafted, claim 3 appears to add no meaningful technical limitation.

The misspelling “dilutent” is unlikely by itself to eliminate the limitation if the meaning is clear from the specification and prosecution history. The more important issue is redundancy and whether claim 3 was intended to distinguish a particular reconstitution vehicle or manufacturing stage.

Claim 4: Quantitative ranges

Claim 4 specifies the following ranges:

Component	Claimed range
Temozolomide	4 wt% to 16 wt%
L-threonine	8 wt% to 20 wt%
Hydrochloric acid	4 wt% to 8 wt%
Citrate buffer	15 wt% to 28 wt%
Polysorbate	4 wt% to 16 wt%
Mannitol	40 wt% to 56 wt%

These ranges are cumulative. A formulation must contain all claim 2 excipients and fall within each stated range.

The ranges create a major interpretation issue. Their minimum values total 75 wt%, while their maximum values total 144 wt%. That alone does not invalidate the claim if the percentages are based on a defined dry-solid fraction, concentrate, or other non-total basis. If they are intended to represent percentages of the complete finished formulation, the claim is internally problematic because the specific components in claim 5 total more than 100 wt%.

Is claim 5 technically consistent?

Claim 5 states approximately:

8 wt% temozolomide;
13 wt% L-threonine;
5 wt% hydrochloric acid;
19 wt% citrate buffer;
49 wt% polysorbate; and
48 wt% mannitol.

The listed amounts total 142 wt%. A conventional formulation cannot contain 142 wt% of its complete composition. This creates several possible interpretations:

The percentages refer to a dry formulation basis;
The percentages refer to separate components or a manufacturing mixture;
One or more claim-transcription errors exist;
The patent specification defines a nonstandard basis;
The claim contains an internal inconsistency relevant to validity.

The issue could support an indefiniteness challenge under 35 U.S.C. § 112(b), particularly if a skilled formulator cannot determine the composition boundaries. It could also affect written-description or enablement arguments if the specification does not explain how the stated percentages are calculated.

The inconsistency does not automatically eliminate infringement exposure. Courts construe claims in view of the specification, prosecution history, and technical meaning. A court could preserve the claim if the patent clearly defines the percentage basis elsewhere.

What is the likely expiration date of US 7,786,118?

The patent appears to claim priority to a December 2004 filing. On a standard 20-year patent-term calculation under 35 U.S.C. § 154, the projected expiration date is in December 2025, subject to:

Patent-term adjustment;
Terminal disclaimers;
Corrected priority information;
Any applicable patent-term extension;
USPTO term calculations.

The patent issued on August 31, 2010. Issuance date does not determine ordinary expiration for a post-1995 US application. The relevant calculation generally begins from the earliest effective nonprovisional filing date, not the issue date.

No basis appears from the claim text for pediatric exclusivity or Hatch-Waxman patent-term extension. Any definitive term analysis must follow the USPTO patent record and continuity data.

What is the Orange Book status of US 7,786,118?

The patent’s Orange Book significance is limited unless it was submitted for listing against an approved temozolomide product and accepted by FDA.

Temozolomide was approved in the United States as TEMODAR capsules and later as an injectable formulation. FDA Orange Book listing depends on the approved product, the NDA holder’s submission, and FDA’s determination that the patent claims an approved drug, formulation, or method of use. A formulation patent is not automatically listed merely because it concerns the active ingredient.

If 7,786,118 is listed against an approved temozolomide product, an abbreviated new drug application applicant could face a Paragraph IV certification. If it is not listed, the patent could still create ordinary patent-infringement risk, but it would not generate the same statutory ANDA litigation mechanism based on an Orange Book listing.

The decisive commercial questions are:

Question	Relevance
Is the patent listed against a temozolomide NDA?	Determines Orange Book-based ANDA exposure
Does the approved product contain L-threonine?	Determines product overlap
Does the approved product use the claimed excipient system?	Determines dependent-claim relevance
Is the formulation patent still unexpired?	Determines present enforceability
Was a Paragraph IV certification filed?	Determines Hatch-Waxman litigation risk

Which companies are challenging temozolomide patents?

Generic competition for temozolomide has historically focused on oral capsules and capsules with different strengths, not necessarily the specific aqueous L-threonine formulation claimed in 7,786,118. Companies active in generic temozolomide have included large generic manufacturers such as Teva, Sun Pharmaceutical, Sandoz, Mylan or Viatris, and other FDA-approved suppliers.

A generic capsule applicant does not necessarily need to address an aqueous formulation patent if the proposed product lacks the claimed aqueous formulation and L-threonine. An applicant for an injectable or reconstituted aqueous product would face a closer infringement analysis.

There is no biosimilar pathway for temozolomide. Temozolomide is a synthetic small-molecule drug regulated through the ANDA pathway, not a biologic regulated under the Public Health Service Act.

What generic launch scenarios exist?

Oral capsule launch

An oral capsule containing temozolomide but no aqueous diluent and no L-threonine would generally fall outside claim 1 as written. The principal barriers for such a product would be active-ingredient patents, formulation patents directed to capsules, regulatory exclusivity, and any listed method-of-use patents.

Injectable or reconstituted aqueous product

An aqueous product containing L-threonine presents the clearest claim 1 risk. A product containing the full hydrochloric-acid, citrate, polysorbate, and mannitol system faces added claim 2 risk. A product matching the stated ranges and pH could implicate claims 4 through 6.

Formulation design-around

Potential design-around approaches include:

Eliminating L-threonine;
Using a different stabilizing amino acid;
Developing a nonaqueous formulation;
Using a dry solid product that is not combined with an aqueous diluent until administration;
Replacing one or more claim 2 excipients;
Moving outside the quantitative ranges of claims 4 and 5;
Adjusting pH outside the claim 6 range.

Design-around success depends on whether claim 1 is valid and enforceable. Avoiding claims 2 through 6 does not avoid claim 1 if L-threonine remains in an aqueous temozolomide formulation.

How strong is the patent estate for temozolomide?

The patent estate represented by 7,786,118 is narrow in product architecture but potentially broad within its selected formulation concept.

Strength factor	Assessment
Claim 1 breadth	High within aqueous L-threonine formulations
Dependence on specific excipients	Limited for claim 1; substantial for claims 2-6
Quantitative clarity	Weak point because of percentages exceeding 100 wt%
Coverage of oral capsules	Low
Coverage of injectable aqueous products	Potentially high
Biosimilar relevance	None
Orange Book impact	Depends on listing and approved product linkage
Remaining term	Limited if ordinary December 2025 expiration applies
Design-around potential	Meaningful, especially by removing L-threonine

The patent is more relevant to an injectable or reconstituted temozolomide program than to conventional generic oral capsules. Its commercial value also declines sharply after expiration unless a related continuation, divisional, or terminally linked patent remains enforceable.

What patent litigation and settlements affect US 7,786,118?

A Paragraph IV dispute would require an ANDA applicant to address a listed patent covering the relevant approved temozolomide product. The claim text alone does not establish that 7,786,118 generated a statutory litigation event, settlement, or 180-day generic exclusivity period.

For diligence purposes, the relevant litigation records are:

USPTO Patent Center prosecution and continuity records;
FDA Orange Book patent-listing data;
Federal district court complaints under 35 U.S.C. § 271(e)(2);
Federal Circuit decisions;
Any ANDA settlement reported under the Federal Trade Commission’s pharmaceutical-settlement program.

The absence of a claim to temozolomide itself means that litigation would likely focus on formulation overlap, percentage interpretation, claim construction, validity under § 112, and whether the accused product is the claimed pharmaceutical formulation.

What licensing deals relate to the patent?

Temozolomide was originally developed and commercialized through Schering-Plough, later integrated into Merck. Public licensing activity involving the underlying active ingredient does not automatically establish a license to 7,786,118. A license covering this patent would need to identify the patent expressly or include the relevant formulation rights through a broader patent portfolio agreement.

No license can be inferred from ownership history, product commercialization, or a generic supply arrangement. Patent ownership, NDA ownership, and formulation-license rights are separate diligence questions.

Key Takeaways

US 7,786,118 is a formulation patent, not a basic temozolomide compound patent.
Claim 1 requires temozolomide, an aqueous diluent, and L-threonine.
Claims 2 through 6 add a defined excipient system, concentration ranges, and pH.
Oral temozolomide capsules without an aqueous diluent or L-threonine are less likely to implicate the patent.
Injectable or reconstituted aqueous temozolomide products containing L-threonine face the highest risk.
Claims 4 and 5 contain a material percentage-basis problem because the listed values can exceed 100 wt%.
The ordinary projected expiration appears to be December 2025, subject to USPTO term adjustment and continuity details.
The patent has no biosimilar relevance because temozolomide is a small-molecule drug.
Orange Book and Paragraph IV significance depends on whether the patent was listed against an approved temozolomide product.
Removing L-threonine is the most direct design-around strategy against claim 1.

FAQs

Does US 7,786,118 cover Temodar capsules?

Not on the face of the supplied claims. Claim 1 requires an aqueous diluent and L-threonine, while a conventional temozolomide capsule is a dry dosage form.

Can a competitor avoid the patent by replacing L-threonine with another amino acid?

That approach could avoid literal infringement of claim 1 if the formulation contains no L-threonine. Equivalence arguments would depend on the patent’s prosecution history, the function of L-threonine, and the technical differences between the formulations.

Does a pH outside 3.0 to 4.5 avoid all claims?

It may avoid claim 6, but it would not necessarily avoid claims 1 through 5. Claims 1 through 5 do not include the claim 6 pH limitation.

Are the claim 4 weight ranges cumulative?

Yes. A formulation must satisfy each stated component range in addition to the underlying claim 2 limitations. The basis for calculating the percentages is central to the interpretation.

Does patent expiration eliminate FDA exclusivity?

No. Patent expiration and FDA regulatory exclusivity are separate rights. Expiration of 7,786,118 would remove the patent barrier but would not by itself eliminate any remaining orphan-drug, pediatric, new-chemical-entity, or other regulatory exclusivity.

References

United States Patent and Trademark Office. (2010). US Patent No. 7,786,118, pharmaceutical formulation comprising temozolomide.
United States Code. 35 U.S.C. §§ 154, 271(e)(2), and 112.
U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations.
U.S. Food and Drug Administration. (n.d.). Drugs@FDA: FDA-approved drugs.
U.S. Food and Drug Administration. (2019). FDA guidance for industry: Applications covered by section 505(b)(2).
World Intellectual Property Organization. (n.d.). PATENTSCOPE patent search database.

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Argentina	038535	⤷ Start Trial
Argentina	064722	⤷ Start Trial
Argentina	084868	⤷ Start Trial
Austria	397440	⤷ Start Trial
Australia	2003213142	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 7,786,118

Summary for Patent: 7,786,118