WO1999008686A1

WO1999008686A1 - Use of uridine to counter 5-fluorouracil toxicity

Info

Publication number: WO1999008686A1
Application number: PCT/US1998/014179
Authority: WO
Inventors: Simon P. Robinson
Original assignee: Basf Aktiengesellschaft; Basf Bioresearch Corporation
Priority date: 1997-08-21
Filing date: 1998-07-13
Publication date: 1999-02-25
Also published as: AR013424A1; HRP980436A2; AU8388198A

Abstract

The present invention provides a method for inhibiting pyrimidine analogue-induced toxicity in a tissue of a patient undergoing pyrimidine analogue therapy. The method comprises the step of directly contacting the tissue with a therapeutically effective amount of uridine. In one embodiment, the invention provides a method of inhibiting chemotherapy-induced stomatitis in a patient undergoing treatment with a pyrimidine analogue. The pyrimidine analogue is a chemotherapeutic agent which induces stomatitis, such as 5-fluorouracil or 5-fluoro-2'-deoxyuridine, and the tissue is an intraoral tissue, such as an oral mucosal tissue or an intraoral soft tissue.

Description

USE OF URIDINE TO COUNTER -FLUOROURAHTT, TOXTHTTY

BACKGROUND OF THE INVENTION

Many forms of cancer chemotherapy and local radiation therapy cause undesirable side effects (S.T. Sonis in Cancer Principles and Practice of Oncology, 4th Ed. , Chapter 6, pp. 2385-2394 (1993); Loprinzi et al . in Clinical Oncology 741-752 (1995)). For example, the antimetabolite 5-fluorouracil frequently induces stomatitis, which is an inflammatory response of the oral mucosa and intraoral soft tissue structures. Stomatitis generally begins with erythema and edema of the buccal mucosa and tongue, and can progress to painful ulceration and secondary infections. Stomatitis makes eating and drinking painful and often results in malnutrition and dehydration. Currently, chemotherapy-induced stomatitis is managed with oral hygiene and pain relief.

Clearly, there is a need for improved methods of inhibiting stomatitis and other undesirable side effects of 5-fluorouracil in patients undergoing treatment with 5- fluorouracil or a 5-fluorouracil prodrug.

SUMMARY OF THE INVENTION

The present invention is a method for inhibiting, totally or partially, pyrimidine analogue-induced toxicity in a tissue of an individual, such as a patient, undergoing pyrimidine analogue therapy. The method comprises topically administering to the tissue a therapeutically effective amount of uridine . The tissue can be any accessible tissue which shows adverse effects of the pyrimidine analogue, for example, mucosal tissue, such as the gastrointestinal mucosa.

In one embodiment, the invention provides a method of inhibiting chemotherapy-induced stomatitis in a patient undergoing treatment with a pyrimidine analogue. The pyrimidine analogue is a chemotherapeutic agent, such as 5- fluorouracil or 5-fluoro-2 ' -deoxyuridine, which induces stomatitis, and the tissue is an intraoral tissue, such as an oral mucosal tissue or an intraoral soft tissue. In this embodiment, the intraoral tissue is contacted with uridine by applying uridine or a composition comprising uridine directly to the surface of the intraoral tissue.

The disclosed method is a method of inhibiting the toxic effects of a pyrimidine analogue within a selected tissue by the localized administration of uridine to the surface of the tissue. The method, thus, provides local protection from pyrimidine analog toxicity without the limitations and difficulties associated with systemic administration of uridine, such as toxicity and limited availability .

DETAILED DESCRIPTION OF THE TNVENTTON

The present invention relates to the topical administration of uridine to a tissue, such as a tissue of a mammal, undergoing treatment with a pyrimidine analogue to inhibit pyrimidine analogue-induced toxicity. As described herein, Applicants have shown that topical administration of uridine to a mucosal tissue, such as an intraoral tissue, inhibits, partially or totally, stomatitis in individuals to whom a pyrimidine analogue is administered .

Frequent topical application of 5-fluorouracil to the cheek pouch of Syrian hamsters results in both histological and clinical changes (Cherrick et al . , J. Invest . Derm. 63 : 284-286 (1974)). Under these conditions, Applicants have observed a progressive thinning of the oral epithelium along with erythema and, ultimately, ulceration. Such developments are characteristic of chemotherapy-induced oral mucositis in cancer patients (Sonis, supra (1993)) . Thus, this hamster system provides a model for chemotherapy- induced mucositis in cancer patients.

Applicants have made the surprising discovery that the visible erythema and ulceration produced by repeated application of 5-fluorouracil to the hamster cheek pouch is prevented by topical application of uridine. In an initial study, 5-fluorouracil (0.5 mg) in 20 μL water was applied twice daily to the right cheek pouch of 6 Syrian hamsters. By day 14, the cheek epithelium in 5 of the animals had broken down completely, exposing the underlying stroma. A second group of 6 hamsters was treated with a solution of

0.5 mg 5-fluorouracil and 5 mg uridine in 20 μL water twice daily. By day 14, none of these animals had visible erosion of the epithelium.

In a second study, 6 hamsters were treated twice daily with 0.5 mg 5-fluorouracil in 10 μL water. By day 12, 4 of the animals exhibited ulceration of the cheek epithelium. A second group of 6 hamsters was treated twice daily with 0.5 mg 5-fluorouracil in 10 μL water, followed immediately by a solution of 5 mg uridine in 10 μL water. At day 12 none of these animals had visible ulceration of the cheek epithelium. In a third study, a solution of 1 mg 5-fluorouracil in 20 μL water was applied to the cheek pouches of 6 hamsters once daily, followed immediately by the application of 20 μL water. By day 14, 5 of these animals displayed complete breakdown of the epithelium. In this group the median time to ulceration was 14 days. A group of 12 hamsters was treated with the 5-fluorouracil solution (1 mg 5- fluorouracil in 20 μL water) . Of these, 6 were immediately treated with a solution of 2 mg uridine in 20 μL water (low dose) , while the remaining 6 were treated with a solution of 10 mg uridine in 20 μL water (high dose) . After 14 days, none of the 12 uridine treated hamsters exhibited epithelial ulceration. The median time to ulceration was 20 days in the low dose group and 23 days in the high dose group, indicating a dose-related effect.

The ability of uridine to prevent 5-fluorouracil- induced oral mucositis was also compared to that of a uridine prodrug, triacetyluridine . Triacetyluridine is sparingly soluble in water. In two trials, the median time to ulceration of a group of hamsters administered 1 mg 5- fluorouracil and 20 μL of a saturated aqueous triacetyluridine solution was 22 and 17.5 days, while the median time to ulceration in a 5-fluorouracil -only (control) group was 21 days in both trials. In contrast, the median time to ulceration of a group of hamsters treated with 1 mg 5-fluorouracil and 2 mg uridine was 24 and 22 days, while hamsters treated with 1 mg 5- fluorouracil and 10 mg uridine had median times to ulceration of 27 and >29 days. The present invention provides a method of inhibiting the toxic effects of a pyrimidine analogue in a tissue of an individual, such as a human, undergoing pyrimidine analogue therapy. The method comprises directly contacting the tissue with an effective amount of uridine.

The term "directly contacting", as used herein, refers to methods of bringing uridine and at least one surface of the affected tissue into sufficient physical contact for the absorption of uridine by the tissue. Such methods exclude the systemic administration of uridine, wherein, for example, uridine can be delivered to the tissue via the bloodstream. The tissue will generally be a site of rapidly proliferating cells and have an accessible surface. Uridine or a uridine-containing composition can be applied directly, such as topically, to the tissue surface.

The term "pyrimidine analogue", as used herein, refers to a class of anticancer and antiviral agents comprising a pyrimidine ring or a heterocycle derived from a pyrimidine ring by the replacement of one nitrogen atom by carbon or the replacement of one carbon atom by nitrogen. Pyrimidine analogues can also include a glycosyl group, such as a ribosyl, deoxyribosyl or arabinosyl group.

The term "pyrimidine analogue therapy" , as used herein, refers to the administration of a pyrimidine analogue to an individual in need of treatment for an illness (e.g., a patient) for which the pyrimidine analogue is indicated. The individual can be a mammal, such as a human. The pyrimidine analogue can be administered by any suitable method, for example, orally, intravenously, intraperitoneally, or intramuscularly, as is known in the art . The pyrimidine analogue can also be administered as a suitable prodrug, for example, a derivative of the pyrimidine analogue which is metabolized within the body to produce the active form of the drug.

In a preferred embodiment, the pyrimidine analogue is a derivative of uridine or uracil. These include substituted derivatives of uridine and uracil, such as halogen-substituted uracil. Other examples include azauracil, deazauracil, azauridine and deazauridine . Other examples include derivatives of uridine having a modified glycosyl group, such as a deoxyribosyl , dideoxyribosyl or arabinosyl group. Pyrimidine analogues include, but are not limited to, 5-fluorouracil , 5-fluoro-2 ' -deoxyuridine, 5-fluorouridine, 6-azauridine, 5-azacytidine, 3- deazauridine, 5-iodouracil , 5-iodo-2 ' -deoxyuridine, 5-bromo- 2 ' -deoxyuridine, 5-ethyl -2 ' -deoxyuridine, 5-methylamino-2 ' - deoxyuridine, arabinosyluracil , azaribine and dideoxyuracil .

In a specific embodiment, the pyrimidine analogue is 5-fluorouracil , 5-fluoro-2 ' -deoxyuridine or a prodrug thereof. 5-Fluorouracil can be administered intravenously or topically, while 5-fluoro-2 ' -deoxyuridine is usually administered intravenously. 5 -Fluorouracil prodrugs include 5-fluoro-1- (tetrahydrofurfuryl) uracil (tegafur) and 1- (n-hexylcarbamoyl) -5-fluorouracil (carmofur) . 5- Fluorouracil, 5-fluoro-2 ' -deoxyuridine and prodrugs thereof are used to treat a variety of cancer types, including metastatic carcinoma of the breast or gastrointestinal tract, hepatoma and carcinoma of the ovary, cervix, urinary bladder, prostate, pancreas, or oropharynx.

A surface of the target tissue is contacted with an amount of uridine which is sufficient to inhibit the toxic effect (s) of the pyrimidine analogue on the tissue. For the purposes of the present invention, the term "inhibition" of the toxic effeet (s) of a pyrimidine analogue is intended to include the prevention or reduction of the toxic effect (s) or the inhibition of an increase in the toxic effect (s); inhibition may be partial or complete. The quantity of uridine to be administered will be determined on an individual basis and will be determined, at least in part, by consideration of the individual's size, the dose of the pyrimidine analogue the patient is receiving, the severity of the symptoms to be treated and the result sought.

In one embodiment, the invention provides a method of inhibiting pyrimidine analogue- induced stomatitis. The pyrimidine analogue is a pyrimidine analogue which induces stomatitis. In a specific embodiment, the pyrimidine analogue is 5-fluorouracil , 5-fluoro-2 ' -deoxyuridine or a prodrug thereof .

In this embodiment, an intraoral tissue, such as an oral mucosal tissue or an oral soft tissue structure, is contacted with uridine in a manner and dose sufficient for absorption of sufficient uridine by the tissue to have the desired effect (inhibition of toxic effects of a pyrimidine analogue) . For example, uridine or a uridine-containing composition can be applied directly to the surface of the oral tissue as a solution in water, an aqueous buffer or a suitable organic solvent, such as ethanol or dimethylsulfoxide, or an aqueous/organic mixture. Uridine or a uridine-containing composition can also be applied as a solid or in a viscous or gel composition.

In another embodiment, the tissue to be contacted with uridine is a gastrointestinal mucosal tissue, for example, the lining of the stomach or the intestinal lumen. In this embodiment, tissue surface can be contacted with uridine via oral or rectal administration of uridine.

In another embodiment, the tissue to be contacted with uridine is the skin or the scalp. Pyrimidine analogues, in particular 5-fluorouracil and 5-fluoro-2 ' -deoxyuridine, can have deleterious effects on the skin, resulting in, for example, dermatitis, increased pigmentation and atrophy. In this embodiment, uridine or a uridine composition is applied directly to the surface of the skin in the region exhibiting or expected to be vulnerable to the toxic effects of the pyrimidine analogue.

The target tissue can be contacted with uridine or a composition comprising uridine. In one embodiment, the tissue is contacted with a composition comprising a solution of uridine in a suitable solvent, preferably water, an aqueous buffer or dimethylsulfoxide, or in another form appropriate to the target tissue. Uridine can be administered to an intraoral tissue in the form of an aqueous solution, lozenges, chewing gum, troches, gels, pastes, mouthwashes or rinses. Compositions for administration to the skin can comprise uridine dispersed in a suitable matrix. Examples of suitable matrices include mineral oil, petrolatum and waxes, such as paraffin wax and beeswax. The target tissue can be contacted with uridine subsequent to, concurrent with or prior to administration of the pyrimidine analogue. The timing of uridine administration can be based on the pyrimidine analogue treatment protocol. For example, a 5-fluorouracil regimen can consist of a single continuous infusion, or a single daily infusion over a 5 day period. In one embodiment, uridine is administered to the target tissue two or more times daily, for example, about every four hours, during the entire course of pyrimidine analogue treatment.

The invention will now be further and specifically described by the following examples.

EXAMPLES

Materials and Methods

Uridine and tri-O-acetyluridine were purchased from Sigma Chemical Co., St. Louis, MO. 5 -Fluorouracil (also referred to herein as "5-FU") was used as a 50 mg/mL solution purchased from Pharmacia Inc., Columbus, OH.

Uridine solutions were prepared by brief sonication in either sterile water or sterile water adjusted to pH 9.5 with NaOH. A saturated tri-o-acetyl uridine (TAU) solution was prepared by adding 1 gram of powder to 25 mL sterile water and mixing for 72 hours. After centrifugation at 2000 rpm for 5 minutes, any remaining particulate matter was removed by filtration through a 0.45 μm syringe filter (Acrodisc) . Spectroscopic analysis was performed on dilutions of this saturated solution, and the concentration determined on the basis of absorbance at 258 nm and comparison with standard solutions.

Mucositis

Syrian golden hamsters (6 to 23 weeks of age; Harlan Sprague Dawley) were sedated using methoxyflurane inhalation and the right cheek pouch everted. The 5-FU solution was applied topically with a pipette and evenly spread on the upper surface. Test agents were similarly applied to the same area. Animals were weighed daily and scored for mucositis as follows: 0=normal, l=mild erythema, 2=marked erythema, 3=edema or tissue puckering, 4=ulceration.

Results

The data presented in Table 1 show the effects of uridine on 5-fluorouracil -induced oral mucositis. Group 1 was treated with 0.5 mg 5-fluorouracil twice per day. At day 14, 5 of the 6 hamsters in this group exhibited complete breakdown of the cheek epithelium, leaving the underlying stroma exposed. Group 2 was treated with 0.5 mg 5-fluorouracil mixed with 5 mg uridine twice a day. None of these animals (0/6) displayed visible erosion of the epithelial layer on day 14.

Table 1

Topical application 2 x per day in 20 μL water. *number of animals with ulceration of cheek pouch on day 14/number of animals in group. In a second study, 5-fluorouracil was applied topically twice per day in 10 μL water. By day 12, four of the six hamsters in this group exhibited ulceration of the cheek epithelium. In contrast, in a group of six hamsters receiving twice daily doses of 5-fluorouracil followed immediately by 5 mg uridine in 10 μL water, none displayed ulceration at day 12.

Table 2

Topical application 2 x per day in 10 μL water

*number of animals with ulceration of cheek pouch on day

12/number of animals in group.

Table 3 shows the results of a third study which confirmed these initial results. Daily topical application of 1 mg 5-fluorouracil in 20 μL water followed immediately by 20 μL water resulted in 5 of 6 animals exhibiting complete epithelial breakdown after 14 days. However, animals receiving this dose of 5-fluorouracil immediately followed by high dose uridine (10 mg in 20 μL water) or low dose uridine (2 mg in 20 μL water) showed no ulceration on day 14. The median time to ulceration was longer for the animals receiving the high dose uridine and thus, indicated a dose related effect.

Table 3

Topical application once per day in 20 μL water. *Number of animals exhibiting ulceration on day 14/number of animals in group.

Table 4 compares the protective effects of uridine and triacetyluridine in two studies. Daily topical application of 5-fluorouracil (1 mg in 20 μL water) followed immediately by 20 μL water resulted in a median time to ulceration of 21 days in both studies. Animals receiving 5-fluorouracil followed by low dose uridine (2 mg in 20 μL water) had median times to ulceration of 22 and 24 days, while animals receiving high dose uridine (10 mg in 20 μL water) had median times to ulceration of 27 and >29 days. In contrast, administration of 5-fluorouracil followed by 20 μL of a saturated aqueous triacetyluridine solution failed to achieve meaningful protection against ulceration. Table 4

*topical application once per day in 20 μL water. 5-FU first followed by uridine or triacetyluridine.

EQUIVALENTS

While this invention has been particularly shown and described with references to preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. Those skilled in the art will recognize or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments of the invention described specifically herein. Such equivalents are intended to be encompassed in the scope of the claims.

Claims

CT.ATMSWe claim:

1. A method of inhibiting pyrimidine analogue toxicity in a tissue of an individual undergoing pyrimidine analogue therapy, said method comprising directly contacting the tissue with an effective amount of uridine .

2. The method of Claim 1 wherein the tissue is an intraoral tissue.

3. The method of Claim 2 wherein the tissue is an oral mucosal tissue or an oral soft tissue structure.

4. The method of Claim 3 wherein the tissue is selected from the group consisting of: the gingiva, the palate, the buccal mucosa and the lip.

5. The method of Claim 1 wherein the tissue is a gastrointestinal mucosal tissue.

6. The method of Claim 1 wherein the tissue is skin.

7. The method of Claim 1 wherein the pyrimidine analogue is a derivative of uracil or uridine.

8. The method of Claim 7 wherein the pyrimidine analogue is selected from the group consisting of: 5- fluorouracil , 5-fluoro-2 ' -deoxyuridine, 5- fluorouridine, 6-azauridine, 5-azacytidine, 3- deazauridine, 5-iodouracil , 5-iodo-2 ' -deoxyuridine, 5- bromo-2 ' -deoxyuridine, 5-ethyl-2 ' -deoxyuridine, 5- methylamino-2 ' -deoxyuridine, arabinosyluracil , azaribine and dideoxyuracil

9. The method of Claim 7 wherein the pyrimidine analogue is 5-fluorouracil , 5-fluoro-2 ' -deoxyuridine or a prodrug thereof .

10. The method of Claim 9 wherein the pyrimidine analogue is 5-fluoro-1- (tetrahydrofufuryl) racil or 1- (n- hexylcarbamoyl) -5-fluorouracil .

11. The method of Claim 1 wherein the tissue is contacted with a composition comprising uridine.

12. The method of Claim 11 wherein the composition further comprises water or an aqueous buffer.

13. The method of Claim 11 wherein the composition further comprises dimethylsulfoxide .

14. A method of inhibiting stomatitis in an intraoral tissue of a patient undergoing treatment with 5- fluorouracil , 5-fluoro-2 ' -deoxyuridine or a prodrug thereof, comprising directly contacting the tissue with an effective amount of uridine.

15. The method of Claim 14 wherein the intraoral tissue is directly contacted with an aqueous uridine solution.