United States Patent 8,895,557 (ET-743 lyophilised disaccharide stabilization) | Scope, Claims, and US Patent Landscape

United States Patent 8,895,557 is directed to lyophilised (freeze-dried) anti-tumor formulations of ET-743 stabilized with a specific disaccharide excipient (sucrose and/or lactose) at levels sufficient to inhibit conversion of ET-743 into ET-701 during storage. The claim set is built to capture: (i) the stabilized composition with defined ET-701 formation limits; (ii) preferred embodiments by disaccharide identity and excipient ratio; (iii) optional buffering and surfactant systems; (iv) vial/unit-dose presentations with specified amounts; and (v) process claims tied to freeze-drying and to bulk solution preparation. The core IP protection is the storage-stability/impurity-control feature combined with disaccharide type and amount.

What does US Patent 8,895,557 claim cover for ET-743 lyophilised formulations?

Core claim theme: lyophilisation + disaccharide-controlled impurity formation

The independent composition claim (claim 1) requires all of the following:

Drug substance: ET-743 (single anti-tumor compound).
Dosage form: lyophilised composition.
Excipient: disaccharide selected from sucrose, lactose, or combination.
Functional stabilization: disaccharide present in an amount sufficient to inhibit conversion of ET-743 into ET-701.
Quantitative stability limit: less than 2% ET-701 after storage at 5°C for 3 months.

This functional/quantitative impurity constraint is the main boundary between infringement and non-infringement. A manufacturer can design around by either:

switching to a different lyophilisation protectant not recited (or not present at “sufficient amount”), or
using sucrose/lactose but demonstrating ET-701 formation ≥ 2% under the claim’s test conditions (5°C, 3 months), or
moving to a non-lyophilised dosage form (not “lyophilised”), depending on how claim construction is applied.

Composition variants explicitly claimed

US 8,895,557 includes an additional composition claim family that is substantively the same concept but with a different storage condition:

Claim 22: same composition definition (ET-743 + sucrose/lactose) with ET-701 inhibition, but the stability threshold is < 2% ET-701 after storage at 25°C for 3 months.
Claim 1 vs claim 22: both lock onto sucrose/lactose and the impurity-control objective, but they differ in temperature conditions (5°C vs 25°C).

That dual temperature coverage matters for regulatory and lifecycle protection, because it forces generic and follow-on formulation developers to validate stability across at least two conditions that the patent uses as claim-defining criteria.

How broad are the ET-743 + disaccharide composition claims in US 8,895,557?

Claim 1 breadth: disaccharide genus + functional “sufficient amount” + specific impurity limit

Claim 1 covers:

Disaccharide genus: sucrose and/or lactose (broad within this genus).
No explicit ratio in claim 1, only “sufficient amount” to meet the <2% ET-701 criterion after 5°C/3 months.
No explicit buffer or surfactant requirement in claim 1.

Practically, “sufficient amount” will be construed via the objective measurable endpoint (<2% ET-701). That converts the functional requirement into a testable limitation.

Claims 2–3: disaccharide identity narrows to single disaccharide

Claim 2: lactose.
Claim 3: sucrose.

These are narrower than claim 1 but are important because many generic/comparative formulation efforts use a single lyoprotectant (either lactose or sucrose). If a competitor uses lactose only, claim 2 can be asserted even if a sucrose embodiment is not made.

Claims 4–6: explicit ET-743:saccharide weight ratios

Claim 4: ET-743:disaccharide from 1:100 to 1:1500 (w/w).
Claim 5: narrowed to 1:250 to 1:600.
Claim 6: specific ratio about 1:400.

These ratio claims add a second axis of scope beyond “functional sufficiency.” If a competitor meets the <2% ET-701 endpoint but uses disaccharide outside these ratios, claim 1 may still be implicated (depending on whether “sufficient amount” would be met). Conversely, if a competitor tries to stay outside the ratios, claim 1 remains a fallback if their formulation still meets the impurity threshold.

Claims 7–10: optional excipient packages (buffer and surfactant)

Claim 7: composition further comprises a buffering agent.
Claim 8: buffer is selected from:
- phosphate buffer
- citrate buffer
- glycine/HCl buffer
- mixtures.
Claim 9: further comprises a surface-active agent.
Claim 10: surfactant is selected from:
- polyoxyethylene 20 sorbitan monooleate
- polyoxyl 40 stearate
- mixtures.

These claims create additional infringement opportunities if a generic uses the same stabilizer architecture. They do not replace the core ET-701 inhibition requirement; they layer on additional elements.

Claims 11–15: vial/unit presentation with specific amounts

Claim 11: lyophilised formulation is in a vial.
Claim 12: ET-743 present at ~250 micrograms (unit-level).
Claim 13: vial contains approximately:
- 0.25 mg ET-743
- 100 mg sucrose
- 6.8 mg potassium dihydrogen phosphate
Claim 14: ET-743 present at ~1 mg.
Claim 15: vial contains approximately:
- 1.0 mg ET-743
- 400 mg sucrose
- 27.2 mg potassium dihydrogen phosphate

These claims can be powerful in practice because unit-dose packaging is often a commercial reality for injectable products. If a follow-on product uses the same vial dosing and lyophilisation excipient loadings, these dependent claims can attach even if some ratio window claims are missed.

What method claims exist and what parts of manufacturing do they cover?

US 8,895,557 includes process claims that map to stages of formulation development and production.

Freeze-drying process claims

Claim 16: method of making lyophilised ET-743 composition by freeze-drying a bulk solution comprising ET-743 and a disaccharide (sucrose/lactose/combination).
Claim 17: method of reducing formation of ET-701 by freeze-drying a bulk solution comprising ET-743 and the same disaccharide set, yielding a composition according to claim 1.

These claims target the freeze-drying step and the input composition composition. They can matter for manufacturing-side enforcement even if final product testing is contested, because process and product are linked to the same endpoint-stabilized composition.

Bulk solution preparation claims

Claim 18: preparing a bulk solution:
- dissolving ET-743 in an acidic medium
- mixing pre-dissolved ET-743 with other bulk components
- optionally adjusting pH of the final solution.

This suggests the patent’s inventive premise includes ET-743 solubilization and handling conditions upstream of lyophilisation.

Reconstitution and IV infusion claims

Claim 19: method of preparing IV infusion:
- provide a vial with a lyophilised ET-743 composition of claim 1
- add water to reconstitute
- dilute reconstituted solution with an aqueous system.

This is a typical method-of-use style claim that can be asserted indirectly against downstream handling, but its enforceability often depends on who performs the steps (manufacturer vs hospitals vs pharmacy compounders).

Additional formulation package dependencies

Claims 20–21: further comprise buffer and then surface-active agent.
Claims 22–26: another composition family (storage at 25°C for 3 months), with vial and disaccharide identity and optional buffer.

How does the “ET-701 <2%” feature define infringement risk and design-around?

Endpoint-based claim boundary

Both key composition claims use a measurable impurity endpoint:

Claim 1: <2% ET-701 after 5°C for 3 months
Claim 22: <2% ET-701 after 25°C for 3 months

That framing makes claim validity and infringement disputes likely to turn on:

analytical methods for ET-701 quantitation,
the test protocol (storage containers, fill volume, light exposure),
and lot-to-lot variability in ET-701 formation.

From a design-around perspective, a competitor can attempt to:

use a different stabilizer (e.g., different carbohydrate, polyols, amino acids),
use sucrose/lactose but alter lyophilisation cycle parameters, vial fill, or acidity conditions to change impurity formation kinetics while staying outside “sufficient amount” interpreted against the <2% criterion.

However, because claim 1 does not define an exact ratio, staying outside the explicit ratio ranges (claims 4–6) may not be sufficient if endpoint stability still meets <2%.

What patent landscape does US 8,895,557 sit in for ET-743 (trabectedin) reformulation?

Immediate landscape: same invention space is likely crowded by formulation + stability patents

Without external record retrieval here, the structurally relevant landscape categories for ET-743 lyophilised stabilization patents in the US are typically:

Drug substance/compound patents (ET-743 itself): earlier priority, often long expired or near expiration depending on jurisdiction.
Composition patents for injectable presentations: often focus on excipient systems, pH, tonicity agents, buffers, antioxidants, and reconstitution performance.
Impurity control patents: ET-701 formation suppression, including storage-condition-specific endpoints like “<x% impurity after y months at z temperature.”
Manufacturing process patents: freeze-drying cycles, bulk solution preparation (acidic medium), and stabilization strategies during lyophilisation.
Packaging and administration method patents: vial-unit presentation and reconstitution/dilution instructions.

US 8,895,557 is squarely in category 3, with overlapping coverage into categories 2, 4, and 5 via dependent claims.

How to map infringement exposure across a generic or biosimilar-style development plan

Any entrant seeking a US approval pathway for an ET-743 lyophilised injectable will face layered risks:

Product development stage risk: if the same disaccharide excipient strategy is used and endpoint stability is matched, claim 1/22 and their dependent features become central.
Process risk: freeze-drying the same ET-743 + sucrose/lactose bulk solution and reducing ET-701 formation can implicate claims 16–17.
Packaging risk: if the unit dose and excipient loadings resemble the claimed vial compositions in claims 12–15, those dependent claims raise direct infringement probability.
Labeling/handling risk: if training materials or IFUs effectively require the claim 19 sequence (reconstitution then dilution), enforcement can shift to method-of-use claims.

What Orange Book status is implied for US 8,895,557 and what does it signal for Paragraph IV?

The patent claims you provided are formulation- and process-focused and likely map to an injectable drug entry rather than a new active ingredient.

Key implications for Orange Book-driven generic strategy:

If 8,895,557 is listed for the relevant US product, an ANDA filer would typically consider whether to file a Paragraph IV certification targeting this formulation patent, especially if the ANDA product will be lyophilised and uses sucrose and/or lactose to control ET-701.
If it is a formulation patent but not listed, the risk moves toward non-Orange-Book patent enforcement (often still actionable, but it changes the Orange Book litigation and timing framework).

Because you did not provide the Orange Book listing details, dates, assignees, or listed NDA reference, those timing and status inferences cannot be stated as facts here.

Which claim elements are most likely to be litigated: composition endpoint, disaccharide identity, or ratios?

Litigation leverage typically concentrates on claim elements that are:

objectively testable,
central to the inventive step,
and likely to be mirrored in competitor development.

In US 8,895,557, the top dispute points are:

ET-701 quantitation at the claimed conditions
- <2% after 5°C/3 months (claim 1)
- <2% after 25°C/3 months (claim 22)
Disaccharide presence and role
- sucrose vs lactose vs combination
“Sufficient amount” interpretation
- whether the competitor’s disaccharide level is sufficient to inhibit conversion under the patent’s endpoint criteria
Freeze-drying linkage
- whether the competitor freeze-drying process uses the same material inputs and yields the claimed stabilized product
Vial fill composition
- the exact approximate loadings in claims 13 and 15 can become a bright-line infringement inquiry if units match.

Timeline: how to use the claim structure to estimate exclusivity and launch risk windows?

No expiration, priority, or filing dates were provided for US 8,895,557 in your prompt, so a factual exclusivity/expiration timeline cannot be constructed.

What the patent structure does enable, however, is a practical risk workflow:

Near launch window risk: greatest when a prospective generic wants a lyophilised ET-743 product with disaccharide stabilizers and similar storage stability.
Development-stage risk: high if the competitor’s formulation screens sucrose or lactose and tests impurity formation under conditions comparable to the patent endpoints.
Lifecycle risk: dual storage-temperature claims (5°C and 25°C) broaden the time during which stability data might satisfy infringement under either claim.

Key claim-by-claim scope map (infringement relevance matrix)

Claim	Coverage	Main infringement hook	Most important design-around axis
1	Lyophilised ET-743 + sucrose/lactose; endpoint <2% ET-701 at 5°C/3 months	Endpoint + disaccharide genus + lyophilised	Use different stabilizer system; ensure ET-701 endpoint does not meet <2%
2	Lactose embodiment	Disaccharide identity	Replace lactose
3	Sucrose embodiment	Disaccharide identity	Replace sucrose
4–6	ET-743:disaccharide ratio windows	Quantified ratio	Use outside ratio windows, though claim 1 may still apply if endpoint met
7–8	Buffer required; specific buffer selections	Buffer identity + endpoint	Replace with non-listed buffer or remove buffer
9–10	Surfactant required; specific surfactants	Surfactant identity	Replace with non-listed surfactants
11–15	Vial format and unit-dose amounts	Packaging and loading match	Change vial dose/loads or excipient scheme
16	Freeze-drying method with ET-743 + disaccharide	Process step + inputs	Use different process or inputs
17	Method to reduce ET-701 by freeze-drying to claim 1 composition	Process + yield of stabilized endpoint	Avoid producing claim 1 composition
18	Bulk solution preparation in acidic medium + optional pH adjust	Upstream manufacturing conditions	Change solvent/pH handling strategy
19	Reconstitution and IV dilution using vial of claim 1 product	Administration method performed	Change reconstitution/dilution steps or avoid using claim 1 vial

Key Takeaways

US 8,895,557 is an ET-743 lyophilised stabilization patent centered on preventing conversion to ET-701 using sucrose and/or lactose.
The independent composition claims are defined by a measurable impurity endpoint: <2% ET-701 after 5°C/3 months (claim 1) and <2% ET-701 after 25°C/3 months (claim 22).
Scope expands beyond the core composition into buffering and surfactant dependent embodiments, vial/unit-dose embodiments, and manufacturing methods (freeze-drying; acidic-medium bulk preparation; reconstitution/dilution workflow).
Design-around efforts that keep sucrose/lactose but change excipient ratios may still fall under claim 1 if the formulation still meets the <2% ET-701 endpoint under the specified storage conditions.

FAQs

1) Can a competitor avoid infringement by using sucrose but changing ET-743:sucrose ratio?

If the new ratio still produces an ET-743 lyophilised composition with <2% ET-701 after 5°C/3 months, claim 1 can still be implicated because claim 1 uses “sufficient amount” tied to the endpoint rather than a fixed ratio.

2) If the formulation meets <2% ET-701 at 5°C, does it still risk claim 22?

Yes. Claim 22 uses a different test condition: <2% ET-701 after 25°C/3 months. A formulation can meet one temperature endpoint and still infringe the other if both thresholds are satisfied.

3) Do the buffer and surfactant dependent claims matter if the core endpoint is met?

They add narrower hooks. If the competitor’s formulation includes the listed buffers/surfactants, dependent claims become additional theories of infringement layered on top of the core claim.

4) Are the process claims easier to enforce than the composition claims?

They can be. Claims 16–18 tie infringement to specific manufacturing steps, including freeze-drying a bulk solution containing ET-743 and sucrose/lactose and acidic-medium dissolution. Outcome depends on evidence and who controls manufacturing steps.

5) How do vial/unit-dose claims affect generic launch planning?

If an ANDA or follow-on product uses a matching vial presentation and approximate loadings (claims 12–15), it narrows ambiguity around infringement and can increase settlement pressure even when broader ratio/window claims are harder to match.

References (APA)

United States Patent 8,895,557.

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate
Janssen Prods	YONDELIS	trabectedin	POWDER;INTRAVENOUS	207953-001	Oct 23, 2015		RX	Yes	Yes	8,895,557*PED	⤷ Start Trial			Y		⤷ Start Trial
>Applicant	>Tradename	>Generic Name	>Dosage	>NDA	>Approval Date	>TE	>Type	>RLD	>RS	>Patent No.	>Patent Expiration	>Product	>Substance	>Delist Req.	>Patented / Exclusive Use	>Submissiondate

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Argentina	051653	⤷ Start Trial
Argentina	110986	⤷ Start Trial
Austria	E368461	⤷ Start Trial
Australia	2005227421	⤷ Start Trial
Brazil	PI0517238	⤷ Start Trial
Canada	2520979	⤷ Start Trial
China	102018714	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 8,895,557

Which drugs does patent 8,895,557 protect, and when does it expire?

Summary for Patent: 8,895,557