WO2006076376A1

WO2006076376A1 - Topical treatment of solid tumors and ocular neovascularization

Info

Publication number: WO2006076376A1
Application number: PCT/US2006/000843
Authority: WO
Inventors: Kenneth Walter Locke; Takashi Kiyoizumi
Original assignee: Medicinova, Inc.
Priority date: 2005-01-11
Filing date: 2006-01-11
Publication date: 2006-07-20

Abstract

A topical method for treating various cancers, including cervical cancer, macular degeneration, melanoma and other skin cancers, by topical administration of a pharmaceutical composition comprising: formula (I) wherein X = O or S, Y is -OR4, -NHR4, -NHAc, -NHAIa, -NHSer, -NHGIu, -NHLys, -NHSuc, -NH(nitro)Arg, -NH(O)COR4, -NH(O)NHR4, -COOR4, where R4 is H, C1-6 alkyl, phenyl, benzyl or phosphate; R1 is selected from -OR, -NRR, and -SR where R is independently H, C1-6 alkyl, phenyl, or benzyl; R2 is selected from H or C1-6 alkyl; and R3 is H, -OH, or -OR5 where R5 is C1-6 alkyl, phenyl or benzyl or a pharmaceutically acceptable salt, solvate, hydrate, or prodrug thereof.

Description

TOPICAL TREATMENT OF SOLID TUMORS AND OCULAR NEOVASCULARIZATION

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This PCT application claims the benefit of U.S. Provisional Application

No. 60/642,521 , filed January 11 , 2005, and the entire disclosure of which is incorporated by reference herein.

FIELD OF THE INVENTION

[0002] Use of benzimidazole carbamates to treat diseases involving neovascularization.

BACKGROUND OF THE INVENTION

[0003] The present invention relates to the topical treatment of cancers, including human melanoma, basal and squamous cell skin cancer, and other potentially fatal skin diseases such as cervical cancer using compounds that inhibit neovascularization. Conventional treatment for cutaneous melanoma involves excision with a deep and wide margin of normal-appearing tissue surrounding the tumor, depending on the depth and thickness of the cancerous mole. Unfortunately, microscopic satellite sites occurring in the skin surrounding the melanoma may be disturbed, and host resistance may be reduced following the excision of the melanoma. A decrease in host resistance may result in the appearance of cancer in distant sites of the body (metastases). Although it is common to excise a margin of tissue surrounding the tumor, increasing the size of the surgical margin to a greater and greater extent usually does not affect survival rate. Thus, there is a need for topical anti-cancer treatments either to augment surgical excision of a tumor or as an alternative to the surgical approach.

[0004] U.S. Patent 6,645,950 discloses a large class of benzimidazole compounds having vascular-damaging activity that may be used for treating tumors by systemic administration. The active compounds are generically said to be topically active but no working examples are given, and no specific compounds is said to be topically active. We have found that a selected group of these compounds is highly effective in topical treatment of cancer and for diseases of the eye involving neovascularization,

SUMMARY OF THE INVENTION

[0005] One object of the invention is to provide a method for treating cancer, comprising: topically administering to a subject in need thereof an effective amount of a pharmaceutical composition containing a compound of formula:

wherein X = O or S,

[0006] Y is -OR₄, -NHR₄, -NHAc, -NHAIa, -NHSer, -NHGIu, -NHLys, -NHSuc, -

NH(nitro)Arg, -NH(O)COR₄, -NH(O)NHR₄, -COOR₄, where R₄ is H, C_1-6alkyl, phenyl, benzyl or phosphate;

[0007] R₁ is selected from -OR, -NRR, and -SR where R is independently H,

Ci-₆ alkyl, phenyl, or benzyl;

[0008] R2 is selected from H or Ci-βalkyl; and

[0009] R₃ is H, -OH, or -OR₅ where R₅ is C-ι-₆ alkyl, phenyl or benzyl

[0010] or a pharmaceutically acceptable salt, solvate, hydrate, or prodrug thereof.

[0011] Another object is to provide a topical method for treating cancers including skin cancers such as squamous cell carcinoma, basal cell carcinoma and malignant melanoma; cervical, vulvar and vaginal cancers; cutaneous T-cell lymphomas, head and neck cancers and Kaposi sarcoma. [0012] Another object is to provide a topical cancer treatment administered in a cream, ointment or transdermal patch.

[0013] One object of the invention is to provide a method for treating ocular neovascularization, comprising: administering to a subject in need thereof an effective amount of a pharmaceutical composition containing a compound of formula:

wherein X = O or S,

[0014] Y is -OR₄, -NHR₄, -NHAc, -NHAIa, -NHSer, -NHGIu, -NHLys, -NHSuc, -

NH(nitro)Arg, -NH(O)COR₄, -NH(O)NHR₄, -COOR₄, where R₄ is H, Ci_-6 alkyl, phenyl, benzyl or phosphate;

[0015] Ri is selected from -OR, -NRR, and -SR where R is independently H,

C-ι-₆ alkyl, phenyl, or benzyl;

[0016] R₂ is selected from H or Ci_-6 alkyl; and

[0017] R₃ is H, -OH, or -OR₅ where R₅ is C_1-6 alkyl, phenyl or benzyl

[0018] or a pharmaceutically acceptable salt, solvate, hydrate, or prodrug thereof.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] This invention relates to substituted benzimidazoles in the preparation of medicaments for the treatment of diseases involving neovascularization. Formation of new vasculature by angiogenesis is an important pathological feature of several diseases (J Folkman, New England Journal of Medicine 333, 1757-1763 (1995)). For example, for a solid tumor to grow it must develop its own blood supply upon which it depends for provision of oxygen and nutrients. If this blood supply is mechanically shut off the tumor will undergo necrotic death. Neovascularization is also a clinical feature of skin lesions in psoriasis, of the invasive pannus in the joints of rheumatoid arthritis patients and of atherosclerotic plaques. Retinal neovascularization is pathological in macular degeneration and in diabetic retinopathy. In all these diseases reversal of neovascularization by damaging the newly-formed vascular endothelium is expected to have a beneficial therapeutic effect.

[0020] The preferred compounds of the invention generally reduced vascular volume by >50% and produced a necrosis score greater than 6 (of 10) at doses of 100 mg/kg ip or less in a mouse breast adenocarcinoma (CaNT) xenograft model described in the examples.

[0021] Compounds of the present invention have the structure 1 :

wherein X = O or S,

[0022] Y is -OR₄, -NHR₄, -NHAc, -NHAIa, -NHSer, -NHGIu, -NHLys, -NHSuc, -

[0023] R₁ is selected from -OR, -NRR, and -SR where R is independently H,

C-|.₆ alkyl, phenyl, or benzyl;

[0024] R₂ is selected from H or Ci_-6 alkyl; and

[0025] R₃ is H, -OH, or -OR₅ where R₅ is C_1-6 alkyl, phenyl or benzyl

[0026] or a pharmaceutically acceptable salt, solvate, hydrate, or prodrug thereof. [0027] A preferred compound is formula 3 (compound 607 in table 1 ; MN-

022):

[0028] Another preferred compound is the N-acetyl derivative (compound 605;

MN-021).

[0029] Another preferred compound is formula 4 (compound 615; MN-029):

[0030] The compounds of the invention may be prepared as described in U.S.

6,645,950, incorporated herein by reference. Example 4 in U.S. 6,645,950 describes methyl[5(6)-(4-aminophenylthio)-1 H-benzimidazol-2yl]carbamate, which is the compound of formula 3 (MN-022). Example 5 of the '950 patent discloses the compound methyl[5(6)-(4-alanylaminophenylthio)-1 H-benzimidazol-2yl]carbamate, which is formula 4 (MN-029).

[0031] In addition to treatment of human melanoma, basal and squamous cell skin cancer, the compounds of the present invention are also effective in the treatment of neoplasms and carcinomas of the larynx, mouth, accessory nasal sinuses, lips, breast and anal region, sarcomas, actnic and seborrheic keratoses, keratoacanthoma, hemangiomas, lymphangiomas, nevi, warts and other miscellaneous epithelial growths

[0032] With respect to ocular neovascularization, besides wet (exudative) age- related macular degeneration (AMD) (also known as choroidal neovascularization), the compounds of the invention may be used to treat a number of other conditions involving neovascularization, including myopic macular degeneration, corneal neovascularization, neovascular glaucoma (iris), choroidal neovascularization due to myopia, (ocular histoplasmosis, etc,) vitreoretinal neovascularization due to ischemia (proliferative diabetic retinopathy, radiation retinopathy, retinopathy of prematurity etc), due to inflammation (retinal vasculitis, sarcoidosis, toxoplasmosis, uveitis, etc.), others (choroidal melanoma, retinoblastoma, chronic retinal detachment, retinitis pigmentosa, etc.), optic nerve head neovascularization, and sickle cell retinopathy.

[0033] Pharmaceutical carriers for topical application are well known to those skilled in the art to enhance penetration or delivery to the site of neovascularization as well as facilitating delivery, such as adhesives.

[0034] Paste formulations may be made with xanthan gum, ethoxylated lanolin, or stearic acid, alkyl polyglycosides, turmeric, titanium dioxide, galangal, or equivalent substitutes.

[0035] Topical compositions of the invention generally contain an emollient in addition to the active ingredient, and may also contain terpenes and essential oils. Suitable emollients include triglyceride esters such as vegetable and animal fats and oils, such as palm oil, castor oil, cocoa butter, safflower oil, cottonseed oil, corn oil, olive oil, cod liver oil, almond oil, avocado oil, palm oil, sesame oil, squalene, kikui oil and soybean oil; acetoglyceride esters, including acetylated monoglycerides; ethoxylated glycerides such as ethoxylated glyceryl monostearate; alkyl esters of fatty acids having 10 to 20 carbon atoms which include methyl, isopropyl and butyl esters of fatty acids; alkenyl esters of fatty acids having 10 to 20 carbon atoms such as oleyl myristate, oleyl stearate, and oleyl oleate; fatty acids having 10 to 20 carbon atoms such as pelargonic, lauric, myristic, palmitic, stearic, isostearic, hydroxystearic, oleic, linoleic, ricinoleic, arachidic, behenic, and erucic acids; fatty alcohols having 10 to 20 carbon atoms such as lauryl, myristyl, cetyl, hexadecyl, stearyl, isostearyl, hydroxystearyl, oleyl, ricinoleyl, behenyl, erucyl, and 2-octyl dodecanyl alcohols; lanolin and lanolin derivatives including, but not limited to lanolin, lanolin oil, lanolin wax, lanolin alcohols, lanolin fatty acids, isopropyl lanolate, ethoxylated cholesterol and lanolin alcohols; polyhydric alcohol esters, including but not limited to, ethylene glycol mono and di-fatty acid esters, diethylene glycol mono- and di-fatty acid esters and polyethylene glycol (200-6000) mono- and di-fatty acid esters; wax esters such as beeswax, spermaceti, myristyl myristate, stearyl stearate; beeswax derivatives including polyoxyethylene sorbitol beeswax; vegetable waxes including camauba and candelilla waxes; phospholipids such as lecithin and derivatives; sterols including cholesterol and cholesterol fatty acid esters; and amides such as fatty acid amides, ethoxylated fatty acid amides, and solid fatty acid alkanolamides.

[0036] Preferred vehicles for topical administration include hydroxypropylbetacyclodextrin (HPBCD) and cyclodextrins.

[0037] The concentration range of active ingredient in topical applications is generally 0.1 to 30 wt.%, preferably 1 to 15 wt.%, and more preferably 3 to 10 wt.%.

[0038] Concentrations of the active compound in eyedrops generally range from 0.1 - 10 wt.%.

[0039] The methods of the invention may be used alone or in combination with other treatment modalities including, but not limited to, radiation, angiogenesis inhibitors and other topical agents.

[0040] Additional anti-cancer compounds which may be administered include

Taxol (paclitaxel), a natural plant alkaloid derived from the yew tree (Taxus brevifolia, Taxus yannanensis), which is a well known microtuble-stabilizing chemotherapeutic agent for the treatment of many cancers, including melanoma. Flurouracil is used in the topical treatment of actinic keratoses, squamous cell carcinoma in situ (Bowen's disease) and basal cell carcinoma. (Fitzpatrick T B, et al. Dermatology in General Medicine, McGraw-Hill 1999 p. 2768-2769.) Fluorouracil may be administered at concentration of 0.1 - 1 wt.%.

[0041] Urea is a widely used dermatologic keratolytic agent that dissolves the intercellular matrix thereby enhancing the absorption of the active compound into the skin through the dead keratin layer. Urea may be administered at a 0.01 - 5 wt.% concentration.

[0042] The compositions of the present invention may include immunological adjuvants and/or chemotherapeutic agents such as 5-fluorouracil, imiquimod, podophyllum, paclitaxel, BCNU, DTIC, Cisplatinum, Tamoxifen, Vinblastine, Bleomycin, Interferon, lnterleukin 2, or Melanoma Vaccine.

EXAMPLES

Table 1:

Biological Activity - Activity Against Tumor Vasculature Measured by Fluorescent Dye

[0043] Functional vascular volume was assessed twenty-four hours after drug treatment following a published procedure (Dark, G. G., Hill, S. A., Prise, V. E., Tozer, G. M., Pettit, G. R., and Chaplin, D. J. Combretastatin A-4, an agent that displays potent and selective toxicity toward tumor vasculature. Cancer Res., 57: 1829-34, 1997). CaNT tumor-bearing mice were treated i.p. with the test compounds formulated in DMSO or in water. Twenty-four hours later the DNA-binding fluorescent dye Hoechst 33342 (10 mg/kg) was injected via the tail vein into treated and untreated mice. One minute later the mice were sacrificed and tumours excised, frozen, sectioned and visualised under UV excitation. Hoechst 33342 can be visualised using UV excitation at 376 nm, with a 418 nm long pass barrier filter. Blood vessels are identified by their fluorescent outlines and vascular volume is quantified using a point scoring system. A graticule with a random array of 25 points is focused on an area of the section and points falling inside rings of fluorescent cells are scored as positive. This is repeated, moving randomly over different areas of the tissue, until 3000 points in total have been accumulated from sections cut at the 3 different levels (ie. by scoring 120 fields per tumour level). This sample size was chosen to give a relative standard error of approximately 10% on the measured volume fraction. The vascular volume fraction for each sample is calculated as the ratio of positive to total points. Results were expressed as percentage vascular volume compared to control tumors.

[0044] The activities of the above compounds in this assay are shown in Table 2:

Table 2: Vascular volumes. All i.p. in CaNT.

Necrosis scores for compounds administered by different routes in CaNT. Ca NT- bearing mice were treated i.p. with test compounds and tumors excised 24 h later. After fixation in formalin, sections were made from paraffin-embedded tumors and stained with hematoxylin and eosin. Sections were scored under the microscope in a blinded fashion according to the following scale: 0-10% necrosis = 1 , 11-20% necrosis = 2, and so on until 91-100% necrosis =10. Results are calculated as the mean of section scores from at least three tumors.

Table 3: Necrosis scores, ail i.p. in CaNT

Necrosis scores for compounds administered by different routes in CaNT Table 4:

Example 1 - Methyl [5(6)-(4-Aminophenylthio)-1H-benzimidazol-2yl]carbamate

[0045] Methyl [5(6)-(4-(acetylamino)phenylthio)-1 H-benzimidazol-

2yl]carbamate (602 mg, 1.78 mmol) was dissolved in mixture of. methanol (24 ml) and hydrochloric acid (10%, 6 ml) and heated under reflux for 16 h. The solution was neutralized with ammonia solution and the methanol removed under reduced pressure. The white precipitate was collected by filtration, washed with water and dried in vacuo to give 392 mg of a pale yellow solid m.p. 282-284 ⁰C. m/e 298 (M⁺).

Example 2 - Methyl [5(6)-(4-Alanylaminophenyjthio)-1H-benzimidazol- 2yl]carbamate

[0046] A suspension of methyl [5(6)-(4-(N.alpha.-tert- butoxycarbonylalanylamino)phenylthio)-1H-benzimidazol-2yl]carbamate (250 mg) in dichloromethane (20 ml) was treated with trifluoroacetic acid (4 ml). The mixture was allowed to warm to room temperature and concentrated under reduced pressure. Ethyl acetate was added and the mixture concentrated again. The residue was triturated with diethyl ether to afford the trifluoroacetic acid salt of the title compound (105 mg) as a white solid m.p. 178-182⁰C. m/e 485 (M+).

Example 3

[0047] Tumors are preferably biopsied before treatment and if the lesion is found to be benign, there is no further treatment. If the biopsy concludes cancerous tissue, a mixture containing 10 wt.% of methyl[5(6)-(4-aminophenylthio)-1 H- benzimidazol-2yl]carbamate (MN-022; compound 607 of Table 1) in hydroxypropylbetacyclodextrin is placed on the clinically judged site of malignant involvement. The mixture is reapplied weekly for 4 weeks at which time the area of the lesion becomes gray and necrotic with surrounding inflammation and at one to two weeks the tumor sloughs off spontaneously or is easily removed with a forceps. A clean base of granulation tissue is achieved, which heals spontaneously by second intention with good or acceptable cosmetic results. If persistence occurs a second or third application of the composition is performed. The skin cancer site is observed intermittently over a five year period for any evidence of local recurrence. Similar results are obtained with compounds 605, 609, 615 and 637.

Example 4

Compounds 605, 607, 609, 615 and 637 of Table 1 are incorporated into medicaments for treating squamous cell carcinoma, basal cell carcinoma, malignant melanoma; a cervical, vulvar or vaginal cancer; a cutaneous T-cell lymphoma, a head or neck cancer; or Kaposi sarcoma by applying a mixture containing 10 wt.% of the active compound on the clinically judged site of malignant involvement and reapplying the mixture for 4 - 12 weeks at which time the area of the lesion becomes gray and necrotic with surrounding inflammation and the tumor sloughs off spontaneously or is easily removed with a forceps. A clean base of granulation tissue is achieved, which heals spontaneously by second intention with good or acceptable cosmetic results.

[0048] Although several embodiments have been described in detail for purposes of illustration, various modifications may be made to each without departing from the scope and spirit of the invention. Accordingly, the invention is not to be limited, except as by the appended claims.

Claims

Claims:

1. A method for treating cancer, comprising: topically administering to a subject in need thereof an effective amount of a pharmaceutical composition containing a compound of formula:

wherein X = O or S,

Y is -OR₄, -NHR₄, -NHAc, -NHAIa, -NHSer, -NHGIu, -NHLys, -NHSuc, -NH(nitro)Arg, -NH(O)COR₄, -NH(O)NHR₄, -COOR₄, where R₄ is H, C_1-6alkyl, phenyl, benzyl or phosphate;

R₁ is selected from -OR, -NRR, and -SR where R is independently H, C_halky!, phenyl, or benzyl;

R₂ is selected from H or C^alkyl; and

R₃ is H, -OH, or -OR₅ where R₅ is Ci_-6 alkyl, phenyl or benzyl

or a pharmaceutically acceptable salt, solvate, hydrate, or prodrug thereof.

2. The method of claim 1 , wherein X is S.

3. The method of claim 2, wherein R₁ is -OCH₃ and Y is -NH₂, -NHAc or -NHAIa.

4. The method of claim 1 , wherein X is O.

5. The method of claim 4, wherein R₁ is -OCH₃ and Y is -NH₂, -NHGIu. 6. The method of claim 1 , comprising a compound of the formula:

wherein X = O or S,

R-_I is selected from -OR, -NRR, and -SR where R is independently H, Ci_-6 alkyl, phenyl, or benzyl;

R₂ is selected from H or Ci-₆ alkyl;

R₄ is selected from -OR, -NRR, and -SR, where R is C-i-e alkyl,

R₅, Re and R₇ are independently H, Ci.β alkyl, phenyl, and benzyl;

or a pharmaceutically acceptable salt, solvate, hydrate, or prodrug thereof.

7. The compound of claim 6, wherein X is S and R₅ , Re and R₇ are H.

6. The method of claim 1 , wherein the cancer is a skin cancer selected from squamous cell carcinoma, basal cell carcinoma and malignant melanoma; a cervical, vulvar or vaginal cancer; a cutaneous T-cell lymphoma, a head or neck cancer; or Kaposi sarcoma.

7. The method of claim 1 , wherein the active compound is administered in a cream or ointment.

8. The method of claim 7, wherein the concentration of the active compound in the cream or ointment is 0.1 to 10 wt.%.

9. The method of claim 1 , wherein the active compound is administered in a transdermal patch.

10. The method of claim 6, wherein X is S.

11. A method for treating conditions of the eye involving neovascularizatoin, comprising: administering to a subject in need thereof an effective amount of a pharmaceutical composition containing a compound of formula:

wherein X = O or S,

Y is -OR₄, -NHR₄, -NHAc, -NHAIa, -NHSer, -NHGIu, -NHLys, -NHSuc, -NH(nitro)Arg, -NH(O)COR₄, -NH(O)NHR₄, -COOR₄, where R₄ is H, Ci_-6 alkyl, phenyl, benzyl or phosphate;

R₁ is selected from -OR, -NRR, and -SR where R is independently H, C_h alky!, phenyl, or benzyl;

R₂ is selected from H or Ci_-6 alkyl; and

R₃ is H, -OH, or -OR₅ where R₅ is Ci-₆ alkyl, phenyl or benzyl

or a pharmaceutically acceptable salt, solvate, hydrate, or prodrug thereof.

12. The method of claim 11 , wherein X is S.

13. The method of claim 12, wherein Ri is -OCH₃ and Y is -NH₂, -NHAc or - NHAIa.

14. The method of claim 11 , wherein X is O.

15. The method of claim 14, wherein Ri is -OCH₃ and Y is -NH₂, -NHGIu.

16. The method of claim 11 , wherein the treatment is for ocular neovascularization.

17. The use of a compound of formula 1 in the manufacture of a medicament for the treatment of cancer.

wherein X = O or S,

Y is -OR4, -NHR4, -NHAc, -NHAIa, -NHSer, -NHGIu, -NHLys, -NHSuc, - NH(nitro)Arg, -NH(O)COR4, -NH(O)NHR4, -COOR4, where R4 is H, C1-6 alkyl, phenyl, benzyl or phosphate;

R1 is selected from -OR, -NRR, and -SR where R is independently H, C1-6 alkyl, phenyl, or benzyl;

R2 is selected from H or C1-6 alkyl; and

R3 is H, -OH, or -OR5 where R5 is C1-6 alkyl, phenyl or benzyl

or a pharmaceutically acceptable salt, solvate, hydrate, or prodrug thereof.

18. The use of claim 17, wherein X is S.

19. The use of claim 18, wherein R1 is -OCH3 and Y is -NH2, -NHAc or -NHAIa.

20. The use of claim 17, wherein X is O.

21. The use of claim 20, wherein R1 is -OCH3 and Y is -NH2, -NHGIu.

22. The use of claim 17, comprising a compound of formula 2:

wherein X = O or S,

R2 is selected from H or C1-6 alkyl;

R4 is selected from -OR, -NRR, and -SR, where R is C1-6 alkyl,

R5 , R6 and R7 are independently H, C1-6 alkyl, phenyl, and benzyl;

or a pharmaceutically acceptable salt, solvate, hydrate, or prodrug thereof.

23. The use of claim 22, wherein X is S and R5 , R6 and R7 are H.

24. The use of claim 23, wherein the cancer is a skin cancer selected from squamous cell carcinoma, basal cell carcinoma and malignant melanoma; a cervical, vulvar or vaginal cancer; a cutaneous T-cell lymphoma, a head or neck cancer; or Kaposi sarcoma.

25. The use of claim 24, wherein the medicament formulation is a cream or ointment.

26 The use of claim 25, wherein the concentration of the active compound in the cream or ointment is 0.1 to 10 wt.%.