BACKGROUND OF THE INVENTION

The present invention relates to wound therapy, and in particular to therapeutic treatment of hypertrophic scar tissue.

Scar tissue is formed during healing of wounds, caused for example by b traumatic injury and elective operative incisions. Often unpredictably, hypertrophy of the tissue occurs. Hypertrophic scar formation is characterized by the accumulation of coll type III out of proportion to collagen type I.

Current procedures and materials for wound treatment include the us compounds with potentially serious side effects, to highly invasive excisional procedures.

In accordance with one aspect of the invention, a composition for therapeutic treatment of hypertrophic scar tissue is provided, comprising a non-t transglutaminase inhibitor having a free amino group, or a pharmaceutically acid addition thereof, and a pharmaceutically acceptable carrier or diluent.

According to another aspect of the invention, a method of treating hypertro scar tissue is also provided, comprising applying to the scar tissue an effective amount non-toxic transglutaminase inhibitor having a free amino group or a pharmaceuti acceptable acid addition salt thereof, and a pharmaceutically acceptable carrier or diluent.

Transglutaminases are enzymes present in plasma and various tissues w form isopeptide bonds between reactive giutaminyl groups and the e-amino group of lysi certain proteins. For example, type III procollagen has been shown to be a specific and substrate for transglutaminase. During skin wound healing it appears that type III procoll amino peptide (PUP) is cross-linked to other components of the wound matrix, such as f and fibronectin, by tissue transglutaminase. It is therefore hypothesized that transglutaminase inhibitor having a free amino group is introduced to the wound site, its amino group will preferentially bind to the giutaminyl group, and thus inhibit the inte protein substrate from cross-linking, forming an inert analog-amine adduct instead.

Known non-toxic transglutaminase inhibitors of this type inc

aminoacetonitrile. (dansyi) cadaverine (1,5-diaminopentane), spermidine and putrescine ( 1,4 diaminobutane). All of these compounds are non-toxic primary amines.

More specifically, aminoacetonitrile is a primary aliphatic lower-alkyl (Cl-5 monoamine. Spermidine is a primary aliphatic aklylamine. Putrescine and (dansyi cadaverine are primary aliphatic lower-alkyl (Cl-5) polyamines. Other similar, non-toxi primary amines of these types are also contemplated.

It will be appreciated by those skilled in the art that the active compounds ma be usefully applied in the form of pharmaceutically acceptable acid addition salts such a hydrochlorides and hydrogen sulfates.

The pharmaceutically acceptable carrier is typically a eutectic cream or ointmen to facilitate spreading over the wound area. For topical application, mineral oil has bee found particularly suitable. Other suitable carriers include polyethylene glycols.

For topical applications, the effective amount of the active compound is in th range of 25 to 100 mM, and preferably about 50 mM.

Once the composition is applied to the wound it may advantageously b occiuded with a dressing or incorporated into a transepidermai patch dressing.

It will be appreciated that, although the compositions according to the inventio are particularly useful for topical application to external wounds, it is also to be expected to b of value in the treatment of internal scar tissue. In such cases, the composition may be applie by catheter infusion or by an implantable time release mechanism. One specific example i diffusion through the elastomer coating of a breast implant.

Figures 1 to ⁸ are photographic illustrations of the effects of the composition according to the invention on hypertrophic scar tissue in human patients. DESCRIPTION OF THE PREFERRED EMBODIMENT

In the examples which follow, the active compound employed was putrescine

SUBSTITUTE SHEET ISA/EP

Putrescine was selected as it is naturally occurring, highly specific and readily available.

Putrescine (Sigma Chemical Co., St. Louis, Mo.) was compounded in a eute base (Glaxo Canada Ltd., Toronto, Ont.) at 0.8% (W/V) concentration (50 mM).

Patients applied the ointment daily and occluded the area with Duoderm CG or Actiderm ^R (Convatec, Princeton, N.J.). If removed for any reason the cream was to reapplied as soon as possible. Patients were to report the presence of any reaction wh developed.

All photographic documentation was carried out by the professional medi photography department using similar lighting and techniques for each wound at the vari times recorded. CASE 1

A 32-year old male having burns involving the trunk and lower extremi resulting from a motor vehicle accident was treated. Burn management consisted of excis and grafting of the lower extremities and a full take occurred in all areas except over Achilles tendons bilaterally. The patient was discharged home with contractures of the ri leg preventing full extension.

At a three-week follow-up, the patient was unchanged and gross hypertrophy the right leg and, to a lesser extent, the left leg was apparent. The patient then was trea with the composition of the invention for one month to the right leg only. During this peri ulceration over tendo Achilles healed fully, but that over the left did not show signs improvement despite treatment with dressings. The scars were less hypertrophic on the ri leg.

At a three-month follow-up, the right knee had a full range of movement signs of hypertrophy on the right had resolved, whereas the left side was still quite red raised. The scars on the left also felt quite hard, even though pressure garments w

continuously used.

Figures 1 to 4 are photographs of the patient. Figures 1 and 2 are side an posterior views of the patient prior to treatment while Figures 3 and 4 are ^si ° ^e an posterior views of the patient post-treatment.

The results obtained in this case exemplify the utility of the compositions of th invention in treating early hypertrophy in bum patients, preventing the need for surgica release of contractures, and allowing stabilization of unhealed areas. CASE 2

A 3 -year old female with a scald burn sustained 9 months previously and treate by excision and grafting was treated. The patient had scar contractures which were fairl mature, had fixed deformities of the toes which prevented normal shoe wear, and wa developing minor ulceration from her special footwear.

A composition according to the invention was applied for one month and th scars were seen to soften with improvement in the skin stability over that time period. At three month follow-up, some residual deformity persisted but the patient had regained fu range of motion and was again able to wear normal footwear.

Figures 5 and 6 are photographs of the patient. Figure 5 being taken prior t treatment and Figure 6 post-treatment. These results show the utility of the compositions o the invention in the treatment of mature burn scar tissue. CASE 3

A 12-year old female was presented one year after an iliac crest free bone fla reconstruction for a dermatofibroma of the mandible resected 6 years previously. The patie had gross hypertrophy of her scars along the entire suture line. In the postauricular area, sh had a keloid-Iike scar which caused protruding of the ear itself.

The scars were excised and the patient was treated with a composition of th

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invention for one month. Since the treatment, there has been no recurrence of hypertroph the excised areas. Further follow-up at 6 months reveals maturation of scars and qu similar to that seen typically in much older ones.

Figures 7 and 8 are photographs of the patient. Figure 7 was t pretreatment, while Figure 8 was taken post-treatment. These results show the u of the compositions of the invention in preventing hypertrophic scar tissue formation.

As seen in the first of three cases studied subsequently, skin stability is adversely affected by topical putrescine. In fact, epithelialization occurs more rapidly in presence of the composition of the invention.

The first patient (case 1) was assessed subsequently at two years post injur the Workers Compensation Board physician who found a thirty percent greater rang motion on the treated right lower extremity as compared to the left. He had no evidenc hypertrophic scar contracture on the right at this time. However, there were obv contractures on the left, which was initially the less severely injured extremity. exemplifies the use of the composition of the invention in treating early hypertrophy in patients, preventing the need for surgical release of contractures and allowing stabilizatio unhealed areas.

The second case (case 2) demonstrates the application to established contract with reasonable improvement in appearance and function. It also exemplifies the use o composition under a pressure garment.

The last example (case 3) is that of prophylactic use in a patient pron hypertrophic scar formation. Overall wound healing was not adversely affected hypertrophy was well controlled.

In no case did wounds undergoing treatment fail to heal normally aside varying degrees of hypertrophy. Patients tolerated the composition well. In a pre

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uncontrolled study as well as in the present work virtually no side effects were witnessed. Out of a total of one hundred and fifteen patients treated, only one patient developed a rash which necessitated discontinuance of the treatment. He went on to require excision and grafting o his hypertrophic bum scars. No one else required further revision, being satisfied with the clinical improvement at one year post treatment.

A major advantage of the treatment according to the invention is the ease of use. A once daily application under an occlusive dressing is relatively convenient. Further advantages are the lack of associated morbidity seen with other treatment modulities such as the skin atrophy and painful injection from intralesional steroid treatment. Moreover, anaplasia as seen in irradiated scars is unlikely. It is also apparent that the composition may be readily applied beneath pressure garments.