United States Patent 8,785,415 (Cladribine-Amorphous Cyclodextrin Complex): Claims, Scope, and Patent Landscape

United States Patent US 8,785,415 claims a cladribine-amorphous cyclodextrin complex that is defined by its state (amorphous admixture), internal structure (an amorphous “inclusion complex” fraction plus an amorphous “non-inclusion complex” fraction), and manufacturing conditions (aqueous complexation and lyophilization with defined temperature and time ranges). The claims extend across four functional layers: (i) complex composition, (ii) process for making the complex, (iii) solid oral pharmaceutical composition with “no significant amount of free crystalline cladribine,” and (iv) oral dosing methods for cladribine-responsive conditions and combination regimens.

What is the core inventive concept in the claims?

The patent’s claim language uses a layered definition that narrows what can infringe while still giving multiple entry points for design-around and proving infringement.

A. The complex is defined as an amorphous admixture with two fractions

Claim 1 defines the complex as an intimate amorphous admixture of:

(a) an amorphous inclusion complex of cladribine with an amorphous cyclodextrin, and
(b) amorphous free cladribine associated with amorphous cyclodextrin as a non-inclusion complex.

This is not merely “cladribine and cyclodextrin in one solid.” It requires a specific amorphous microstructure characterization outcome: an inclusion fraction and a non-inclusion-associated fraction, both within an overall amorphous material.

B. The cyclodextrin is limited to specific “amorphous” variants

The amorphous cyclodextrin is defined to include:

hydroxypropyl-β-cyclodextrin (HP-β-CD)
hydroxypropyl-γ-cyclodextrin (HP-γ-CD)
randomly methylated β-cyclodextrin
carboxymethyl-β-cyclodextrin
sulfobutyl-β-cyclodextrin

Dependent claims then narrow further to HP-β-CD and HP-γ-CD in several embodiments.

C. The product is “saturated” with cladribine in multiple claims

Claims 2 and 23 and 47 state the complex is saturated with cladribine.

“Saturated” is a meaningful limitation because it implies a maximum complexation capacity / composition point rather than a dilute or undersaturated formulation.

D. Quantitative fractionation is explicitly claimed

Claims 7, 29, 53, and 60, plus additional method claims, require:

30 to 40 wt% of cladribine in the inclusion complex (a)
60 to 70 wt% of cladribine in the non-inclusion complex (b)

This is a key enforceability lever because it demands a quantifiable phase/fraction distribution within the solid.

E. Composition ratio windows are also explicitly claimed

Claim 5 and 26 and 50 and 58 and related claims:

cladribine : amorphous cyclodextrin = 1:10 to 1:16 (weight ratio)

Claim 28 ties the molar ratio to a phase solubility diagram curve for saturated complexes.

What is the scope of the composition claims (1, 2, 3-7, 22-29, 23-30)?

1. Independent composition claim (Claim 1)

Claim 1 is the foundation:

A complex cladribine-amorphous cyclodextrin
Defined by intimate amorphous admixture of:
- amorphous inclusion complex (a)
- amorphous free cladribine associated with amorphous cyclodextrin as non-inclusion complex (b)

2. Saturation and cyclodextrin selection (Claims 2, 3, 4, 5)

Claim 2: complex is saturated with cladribine
Claim 3: cyclodextrin can be any of the five named amorphous derivatives
Claim 4: cyclodextrin limited to HP-β-CD or HP-γ-CD
Claim 5: weight ratio 1:10 to 1:16

3. Fraction distribution (Claim 7)

inclusion fraction: 30–40 wt%
non-inclusion-associated fraction: 60–70 wt%

4. Pharmaceutical composition layer (Claim 22)

Claim 22 adds formulation and a crystallinity exclusion:

Pharmaceutical composition comprising the complex
Formulated into a solid oral dosage form
Contains no significant amount of free crystalline cladribine

This claim is the typical bridge from material to dosage form. The “no significant amount” phrase is a practical enforcement feature because it targets solid-state behavior and limits the presence of uncomplexed crystalline drug.

5. Composition further narrowed by ratio/fraction (Claims 23-29)

Claim 23: saturated complex
Claims 24-27: cyclodextrin set and ratio window
Claim 28: molar ratio tied to phase solubility diagram point
Claim 29: fraction distribution 30–40 wt% inclusion / 60–70 wt% non-inclusion

6. Process-dependent composition (Claim 30)

Claim 30 claims a pharmaceutical composition obtainable by:

complexation (water, 40-80°C, 6-24 hours)
cooling to room temperature
lyophilizing to afford amorphous product
formulating into solid oral dosage form

This “obtainable by” structure can capture manufacturing variants if they fall within the recited steps and conditions.

How broad is the manufacturing/process coverage (Claim 8-21, and incorporated into Claim 30-43)?

Independent process claim (Claim 8)

Claim 8 recites the process to make the complex:

Combine cladribine + amorphous cyclodextrin in water
Maintain 40–80°C for 6–24 hours
Cool to room temperature
Lyophilize to afford amorphous product

Dependent claims then tightly specify subranges, optional filtration, and lyophilization program details.

Process temperature and time windows

Claim 10: 45–60°C
Claim 11: 45–50°C (narrower)
Claim 13: complexation time 6–9 hours (with stirring)
Claim 14: cooling step period 6–9 hours is stated (the claim text associates it as “step (ii) is performed for … 6 to 9 hours,” which reads as a defined hold after cooling to room temperature)

Stirring and filtration

Claim 12: step (i) performed with stirring
Claim 9: filtration step after cooling (after step ii) in an alternate process embodiment

Lyophilization program is explicitly quantified

Claim 15: initial freezing to -40 to -80°C held 2–4 hours
Claim 16: cooling to about -45°C (example narrowing)
Claim 19: lyophilization stages:
- (a) initial freezing: -40 to -80°C for ~2–4 hours
- (b) primary drying: -25°C for ~80–90 hours
- (c) secondary drying: 30°C for ~15–20 hours
Claim 20: stage (a) at about -45°C for ~3–4 hours
Claim 21: primary drying pressure about 100 mTorr

Example charge levels

Claim 17: two example cladribine charges with constant cyclodextrin:
- 12.00 parts by weight cladribine + 172.50 parts by weight HP-β-CD
- OR 16.35 parts by weight cladribine + 172.50 parts by weight HP-β-CD
Claim 18: 825 parts by volume of water

These example points matter because they may function as the “best mode-like” anchor for claimed composition ratio and saturated complex states, even if infringement can occur outside examples.

What is the infringement-relevant separation between “inclusion complex” and “non-inclusion complex”?

This patent builds an internal compositional narrative into the claim. The inclusion fraction and the non-inclusion-associated fraction are not synonyms; they are distinct required endpoints.

Quantitative limitations to watch

Inclusion fraction: 30–40 wt%
Non-inclusion-associated fraction: 60–70 wt%

A competitor aiming to avoid infringement would need to alter the solid-state distribution outcome, not merely swap excipients or adjust manufacturing timing slightly.

How broad are the method claims (46-79), including “bioavailability enhancement” and “treatment” and combinations?

Method 1: Enhancing oral bioavailability (Claim 46)

Claim 46:

oral administration of the claimed pharmaceutical composition
composition in a solid oral dosage form
no significant amount of free crystalline cladribine
and defined complex structure (inclusion/non-inclusion amorphous admixture)

Dependent claims specify:

saturated complex (47)
cyclodextrin subset (48-49)
ratio window 1:10–1:16 (50-51)
molar ratio tied to phase solubility curve (52)
inclusion fraction (53)

Method 2: Treatment of symptoms in cladribine-responsive conditions (Claim 54)

Claim 54 expands to:

symptoms of a condition selected from:
- multiple sclerosis
- rheumatoid arthritis
- leukemia

Dependent claims then narrow to:

multiple sclerosis (56)
cyclodextrin variants (57)
weight ratio and inclusion fraction (58-60)

Method 3: Treatment plus add-on active ingredients (Claim 61)

Claim 61 is broader than Claim 54 because it includes combination administration:

administering the claimed composition
plus one or more additional active ingredients for treating the cladribine-responsive condition

Dependent claims specify MS combination examples:

interferon beta
glatiramer acetate
natalizumab
alemtuzumab
4-aminopyridine
amantadine (Claim 70)
and further narrow cyclodextrin to HP-β-CD, ratio to about 1:14 or 1:11, and MS application (71-76)

Commercially relevant implication

These dosing claims are not confined to a particular cladribine drug product brand or dose. They attach to the presence of the claimed complex in a solid oral dosage form and to solid-state properties (“no significant amount of free crystalline cladribine”).

Where does this patent sit in the broader cladribine and cyclodextrin formulation landscape?

A. It targets amorphous-state complexation, not conventional inclusion alone

Many cyclodextrin patents cover:

forming inclusion complexes that are characterized by drug encapsulation
improving solubility and dissolution

Here, the claim explicitly requires:

an intimate amorphous admixture
a two-fraction internal structure (inclusion fraction plus non-inclusion-associated free drug fraction)
a crystallinity constraint in the final dosage form layer (“no significant amount of free crystalline cladribine”)

That differentiates it from patents that focus purely on inclusion complex formation and crystallization suppression without specifying the inclusion/non-inclusion fraction breakdown.

B. The patent is anchored on oral solid dosage and lyophilized amorphous product

The process and composition claims focus on:

aqueous complexation
cooling
lyophilization using quantified freeze and drying program parameters

This is likely to matter for both:

enforceability (competitors must match these outcomes)
design-around (alternative drying technologies may fall outside the recited lyophilization schedule, unless “obtainable by” language still captures them in a way a court deems equivalent)

C. It covers a narrow drug set (cladribine) with broad cyclodextrin derivatives

Compared with platform cyclodextrin patents, this one is:

drug-specific (cladribine)
cyclodextrin-diverse within the specific list and “amorphous” condition

This combination is typical of formulation patents that try to preserve room for excipient selection while controlling the core solid-state definition.

Claim-by-claim “scope map” (what is protected)

The following table maps each claim cluster to what it covers and what would likely be required for infringement.

Claim cluster	Covers	Key limitations that control scope
1	Composition of cladribine-amorphous cyclodextrin complex	intimate amorphous admixture; inclusion complex fraction (a) + amorphous non-inclusion-associated fraction (b)
2, 23, 47	Saturated complexes	saturation state
3-6, 24-27, 48-51	Cyclodextrin identity and ratio	cyclodextrin derivative set; HP-β-CD/HP-γ-CD narrowing; cladribine:CD weight ratio 1:10–1:16
7, 29, 53, 60, 74, 77	Fraction distribution	30–40 wt% inclusion / 60–70 wt% non-inclusion-associated
8-21	Process to prepare the complex	40–80°C complexation; 6–24h; lyophilization program (-40 to -80°C freeze 2-4h; -25°C primary drying ~80-90h; ~100 mTorr); optional filtration; stirring; specific freeze setpoints
22, 30, 42-45	Solid oral dosage formulation	no significant free crystalline cladribine; oral solid dosage form; “obtainable by” process limitations
46-79	Oral dosing methods	enhancement of oral bioavailability; treatment of MS/RA/leukemia; combination with additional actives for treating MS via enumerated examples

Design-around pressure points (practical enforcement vectors)

1. Alter the amorphous-state definition

The claims require an amorphous product and an amorphous admixture with two fractions. If a competitor produces a system where cladribine is not amorphous (or where amorphous admixture does not yield the required inclusion/non-inclusion fraction distribution), the claims become harder to satisfy.

2. Shift the inclusion vs non-inclusion fraction distribution

The 30–40 wt% inclusion and 60–70 wt% non-inclusion-associated ranges are explicit. Formulations that still produce amorphous material but yield a different distribution may fall outside.

3. Avoid “no significant amount of free crystalline cladribine”

Final dosage forms are limited by free crystalline cladribine exclusion. A competitor could target a formulation that has a measurable but “significant” crystallinity presence, depending on how “no significant amount” is interpreted and measured.

4. Keep outside the process program

Lyophilization schedules are numerically defined in multiple dependent claims. Using alternative drying processes or lyophilization programs outside recited ranges can be a lever.

Key Takeaways

US 8,785,415 protects a cladribine-amorphous cyclodextrin complex that is defined by amorphous-state microstructure (inclusion fraction plus non-inclusion-associated fraction), not just the presence of cyclodextrin.
The enforceability hinges on quantifiable constraints: cladribine:cyclodextrin weight ratio (1:10 to 1:16) and inclusion fraction (30–40 wt%) with the complement in the non-inclusion-associated fraction.
The patent extends from complex composition to solid oral dosage forms through a crystallinity exclusion: “no significant amount of free crystalline cladribine.”
The process layer is tightly drawn around aqueous complexation (40–80°C, 6–24h) and lyophilization with quantified temperature/time/pressure elements (including -25°C primary drying for ~80–90h and ~100 mTorr pressure in one dependent claim).
Method claims cover oral bioavailability enhancement and treatment of multiple sclerosis, rheumatoid arthritis, and leukemia, including combination regimens with selected MS actives.

FAQs

1) Does the patent require a specific cyclodextrin derivative?

Yes. The claims list specific amorphous cyclodextrin derivatives, with multiple dependent claims narrowing to HP-β-CD and HP-γ-CD.

2) Is “amorphous inclusion complex” the same as “inclusion complex” in typical cyclodextrin patents?

It is narrower here because the claim requires an amorphous inclusion complex fraction plus a defined complementary amorphous non-inclusion-associated fraction, with explicit weight percentages.

3) Can a competitor infringe by making the same complex but using different drying conditions?

The process-dependent claims (and “obtainable by” dosage claims) can be sensitive to whether the manufacturing steps match the recited temperature/time and lyophilization program ranges.

4) Do the method claims cover combination therapy?

Yes. Claim 61 explicitly requires oral administration of the claimed composition with one or more additional actives for treating the cladribine-responsive condition, and dependent claims provide MS example actives.

5) What is the biggest practical constraint for oral dosage forms?

The dosage form claims include “no significant amount of free crystalline cladribine,” tying infringement risk to solid-state characterization of the final product.

References

United States Patent US 8,785,415. Claims as provided in the user prompt.

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
European Patent Office	1608344	⤷ Start Trial	PA2018502	Lithuania	⤷ Start Trial
European Patent Office	1608344	⤷ Start Trial	LUC00065	Luxembourg	⤷ Start Trial
European Patent Office	1608344	⤷ Start Trial	PA2018502,C1608344	Lithuania	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Summary for Patent: 8,785,415