Pulse photodynamic treatment of photodamaged skin

Abstract

The present invention is related to a pulse photodynamic therapy (or pulse PDT) treatment of photodamaged skin.

Claims

1. A method of treating actinic keratosis in a human subject, the method comprising: (a) subjecting actinic keratosis lesions on skin of the subject to a curettage mechanical pretreatment, (b) administering to the pretreated lesions a composition comprising 5-aminolevulinic acid methyl ester or a pharmaceutically acceptable salt thereof, (c) exposing the lesions to natural light for 0.5 to 3 hours, and (d) optionally removing the composition.

2. The method according to claim 1, wherein the composition is removed after exposing the skin to the natural light.

3. The method according to claim 1, wherein the composition is not removed after exposing the skin to the natural light.

4. The method according to claim 1, wherein the composition is in the form of a cream.

5. The method according to claim 1, wherein the natural light is sunlight.

6. The method according to claim 1, wherein the human subject is female.

7. The method according to claim 1, wherein the human subject is male.

8. The method according to claim 1, wherein the mechanical pretreatment removes or perforates the skin stratum corneum.

9. The method according to claim 1, wherein the lesions are located on the skin of the face and/or scalp.

10. The method according to claim 1, wherein the lesions are premalignant.

11. The method according to claim 1, wherein the lesions are malignant.

12. The method according to claim 1, further comprising administering a sunscreen to the skin that will be exposed to the natural light prior to the mechanical pretreatment.

13. The method according to claim 1, wherein the composition is administered to the pretreated lesions 4 to 35 minutes before exposing the lesions to natural light.

14. The method according to claim 1, wherein the composition is administered to the pretreated lesions about 30 minutes before exposing the lesions to natural light.

15. The method according to claim 1, wherein the lesions are exposed to natural light for 2 to 3 hours.

16. The method according to claim 1, wherein (a)-(d) are repeated one or more times 2-4 weeks apart.

17. The method according to claim 1, wherein (a)-(d) are repeated one or more times at least two weeks apart.

18. The method according to claim 1, wherein (a)-(d) are repeated two weeks later.

19. The method according to claim 1, wherein (a)-(d) are repeated twice more, two weeks apart.

20. The method according to claim 1, wherein the composition comprises a pharmaceutically acceptable salt of 5-aminolevulinic acid methyl ester.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a graph showing the inflammation vs. response rate (3 months) of AK on the face.

(2) FIG. 2 is a graph showing the mean increased redness the day after PDT.

(3) FIG. 3 is a graph reporting the visual redness 1 day after PDT with different treatment protocols.

(4) FIG. 4 is a graph showing the pain scale after different treatments.

(5) FIG. 5 is a graph showing the cure rate after different treatments.

(6) FIG. 6 is a graph showing the increase in erythema percentage one day after treatment with different protocols.

(7) FIG. 7 is a graph showing erythema scale after treatment with different protocols.

(8) FIG. 8 is a graph showing the mean photobleaching in the standard treatment and a different “pulse” treatment.

(9) FIG. 9 is a graph showing the inflammation (erythema)/PpIX formation relationship.

(10) FIG. 10 is a graph showing the values of fluorescence by IMP and pre-treatment at 405 nm.

(11) FIG. 11 is a graph showing the values of fluorescence by IMP and pre-treatment at 632 nm.

(12) FIG. 12 is a graph showing TEWL detailed by occlusion and pre-treatment.

EXAMPLES

Example 1—Assessment of the Efficacy of a Daylight PDT in Subjects with Facial Photodamage

(13) A double-blind randomized-controlled trial has been conducted to determine whether daylight PDT is an efficient method for treating photodamaged skin.

(14) 60 Subjects were randomized to receive 1 gram of topical methyl aminolevulinate (MAL) applied to the whole face <30 minutes before sun exposure for 2 hours (3 sessions, 2 to 4 weeks apart) or matching placebo applied to the whole face <30 minutes before sun exposure for 2 hours (3 sessions, 2 to 4 weeks apart) in a double-blind fashion. Neither the investigator nor the patient knew which agent was administered, as it was applied by a trained professional nurse. To enhance product/placebo penetration a subtle abrasion with sandpaper of the whole face was performed. Also, a sunscreen (Cetaphil Dermacontrol SPF30®) was applied to the entire sun-exposed area including the treatment area in both groups during daylight-PDT, to avoid sunburn.

(15) Efficacy was evaluated after 1 month of the third (last) daylight session.

(16) PDT treatment with MAL followed by daylight exposure was found to have a significantly greater treatment effect than placebo followed by daylight exposure; with the majority of patients of the MAL group having facial improvement (14 out of 30 subjects) and 11 out of 30 having facial success (p=0.00, Chi.sup.2 test).

(17) Significant differences were also found in specific photodamage variables:

(18) TABLE-US-00002 Specific photodamage severity scores Metvix Placebo p value Fine lines failure 6 (20%) 27 (90%) 0.000 improvement 13 (43.3%) 2 (6.7%) sucess 11 (36.7%) 1 (3.3%) Mottled pigmentation failure 7 (23.3%) 23 (76.7%) 0.000 improvement 18 (60%) 4 (13.3%) sucess 5 (16.7%) 3 (10%) Sallowness failure 5 (16.7%) 25 (83.3%) 0.000 improvement 9 (30%) 2 (6.7%) sucess 16 (53.3%) 3 (10%) Tactile roughness failure 5 (16.7%) 25 (83.3%) 0.000 improvement 6 (20%) 2 (6.7%) sucess 19 (63.3%) 3 (10%) Coarse lines failure 9 (30%) 27 (90%) 0.000 improvement 15 (50%) 3 (10%) sucess 6 (20%) 0 (0%) Erythema failure 6 (20%) 25 (83.3%) 0.000 improvement 16 (53.3%) 2 (6.7%) sucess 8 (26.7%) 3 (10%)

(19) Pain VAS scores after session 1, 2 and 3 were not significantly different between the two groups, although a little bit more pain was experimented by patients in the placebo group after the second session (below table).

(20) Similarly, there were no statistical differences in the effects experimented by patients by patients one week after sessions, and in some of these variables no effect was found depending on each session (below table).

(21) TABLE-US-00003 Other secondary Metvix Placebo Outcomes (Mean(Median)) (Mean(Median)) P Pain VAS score after 0.80 (0) 0.40 (0) >0.05 session 1 Pain VAS score after 0.60 (0) 1.27 (0) >0.05 session 2 Pain VAS score after 1.13 (0) 8.77 (0) >0.05 session 3 n (%) n (%) Reaction 1 week after session 1 Oozing 0 30 (100%) 30 (100%) * 1 0 (0%) 0 (0%) 2 0 (0%) 0 (0%) 3 0 (0%) 0 (0%) Erythema 0 20 (66.7%) 25 (83.3%) >0.05 1 8 (26.7%) 5 (16.7%) 2 2 (6.7%) 0 (0%) 3 0 (0%) 0 (0%) Oedema 0 30 (100%) 30 (100%) * 1 0 (0%) 0 (0%) 2 0 (0%) 0 (0%) 3 0 (0%) 0 (0%) Desquamation 0 16 (53.3%) 23 (76.7%) >0.05 1 9 (30%) 5 (16.7%) 2 5 (16.7%) 2 (6.7%) 3 0 (0%) 0 (0%) Pigmentation 0 29 (96.7) 29 (96.7%) >0.05 1 1 (3.3%) 1 (3.3%) 2 0 (0%) 0 (0%) 3 0 (0%) 0 (0%) Vesiculation 0 30 (100%) 30 (100%) * 1 0 (0%) 0 (0%) 2 0 (0%) 0 (0%) 3 0 (0%) 0 (0%) Reaction 1 week after session 2 Oozing 0 30 (100%) 30 (100%) * 1 0 (0%) 0 (0%) 2 0 (0%) 0 (0%) 3 0 (0%) 0 (0%) Erythema 0 19 (63.3%) 22 (73.3%) >0.05 1 11 (36.7%) 8 (26.7%) 2 0 (0%) 0 (0%) 3 0 (0%) 0 (0%) Oedema 0 30 (100%) 30 (100%) * 1 0 (0%) 0 (0%) 2 0 (0%) 0 (0%) 3 0 (0%) 0 (0%) Desquamation 0 15 (50%) 23 (76.7%) >0.05 1 12 (40%) 7 (23.3%) 2 3 (10%) 0 (0%) 3 0 (0%) 0 (0%) Pigmentation 0 29 (96.7%) 30 (100%) >0.05 1 1 (3.3%) 0 (0%) 2 0 (0%) 0 (0%) 3 0 (0%) 0 (0%) Vesiculate 0 38 (100%) 30 (100%) * 1 0 (0%) 0 (0%) 2 0 (0%) 0 (0%) 3 0 (0%) 0 (0%) Reaction 1 week after session 3 Oozing 0 30 (100%) 30 (100%) * 1 0 (0%) 0 (0%) 2 0 (0%) 0 (0%) 3 0 (0%) 0 (0%) Erythema 0 23 (76.7%) 26 (86.7%) >0.05 1 7 (23.3%) 4 (13.3%) 2 0 (0%) 0 (0%) 3 0 (0%) 0 (0%) Oedema 0 30 (100%) 30 (100%) * 1 0 (0%) 0 (0%) 2 0 (0%) 0 (0%) 3 0 (0%) 0 (0%) Desquamation 0 15 (50%) 22 (73.3%) >0.05 1 12 (40%) 8 (26.7%) 2 3 (10%) 0 (0%) 3 0 (0%) 0 (0%) Pigmentation 0 26 (86.7%) 28 (93.3%) >0.05 1 4 (13.3%) 2 (6.7%) 2 3 (10%) 0 (0%) 3 0 (0%) 0 (0%) Vesiculation 0 30 (100%) 30 (100%) * 1 0 (0%) 0 (0%) 2 0 (0%) 0 (0%) 3 0 (0%) 0 (0%)

Example 2—Comparison of Mechanical Penetration Enhancers on Photosensitizer Skin Penetration

(22) The effect on the product skin penetration of different mechanical penetration enhancement techniques (occlusion, microneedles, ablative fractional laser) has been evaluated.

(23) 10 healthy volunteers have been treated according to the following protocol: pretreatment with either micro-needles (Dermaroller) or ablative fractional laser (CO.sub.2 laser fraxel repair (SOLTA)), or no pretreatment; application of Metvix; 3 hours of incubation with or without occlusion. Penetration was quantified during incubation using measurement of photo fluorescence of PpIX at 30 minutes, 1 hour, 2 hours, and 3 hours after product application.

(24) Both Dermaroller and laser similarly increased Metvix penetration in surface and deeper skin as measured by blue (405 nm) (see FIG. 10) and red (632 nm) (see FIG. 11) photo fluorescence as compared to no pretreatment without occlusion and no pretreatment with occlusion.

(25) No difference was observed with or with occlusion before 3 hours.

(26) In addition, laser pretreatment was found to be more painful and more irritant than Dermaroller, and laser pretreatment has more impact in lowering skin barrier function as observed by measuring transepidermal water loss (see FIG. 12).

(27) Therefore, the inventors have surprisingly shown that mechanical pretreatment with a device such as micro-needle device is as efficient as a laser pretreatment to increase product skin penetration but with less adverse events and is therefore more adapted to the PDT treatment of photodamaged skin.

Example 3—PDT Procedure Change to Minimize Inflammation in PDT

(28) According to the just mentioned theory it would be preferable to keep PPIX and cellular enzymes away from the extracellular compartment, thereby avoiding inflammation. The purpose of this project is therefore to keep the PPIX formation within the mitochondria and avoid excess amounts of PPIX to be formed. Simultaneously PPIX should be allowed to be formed for such a long time that most unnormal cells will be affected.

(29) So the purpose of PDT is to kill unnormal cells, preferably by apoptosis. The ideal situation would be to keep PPIX inside the cell and to destroy the mitochondria only, thereby inhibiting the ATP formation necessary for cell functions. That should result in cell death by apoptosis.

(30) One possible way to achieve this would be to give a short 5-MAL pulse treatment to get a high concentration of 5-MAL in the cells initially and then diminish further access to 5-MAL by removing 5-MAL from the skin surface.

(31) This could be done by only exposing the skin to 5-MAL for a short time, after which all 5-MAL is removed from the skin surface. If the right “pulse time” can be found it might ensure high cellular PPIX and low extracellular PPIX. Excess amounts of PPIX formation during and after the end of the treatment would thus be avoided.

(32) The result shows less inflammation with unchanged efficacy and thus mitochondria destruction seems to be the most important factor in PDT.

(33) To estimate the preferable Metvix “pulse time” a separate investigation was performed (Method B) on 24 healthy volunteers. The pulse time was 20 min., 40 min., 60 min., and the conventional 180 min, after which excess amounts of Metvix was removed from the skin. The formation of PPIX after 3 hours is seen in FIG. 8, and the relation to inflammation is seen in FIG. 9. It is seen that PPIX concentration speeds up between 20-40 min. of “pulse exposure”, and so we have chosen 30 min. as the minimum “pulse exposure” time in the following (Method A) investigation of efficacy and inflammation by this method change. The results are illustrated in Column 3 in FIGS. 4, 5, 6, and 7. The procedure change clearly diminishes inflammation (erythema), without affecting the cure rate (FIG. 5). Pain level is not changed. PPIX concentration is clearly lower than for the conventional 3-hour exposure to Metvix (Table 1 and FIG. 8).

(34) Methods

(35) Healthy Volunteers

(36) Twenty-four healthy male volunteers of Scandinavian ancestry were included in the study (mean age 30 years, range 20-51). A treatment area was selected on the inside of both forearms of the volunteer. Each treatment area was divided into four minor treatment fields of the size 2×5 cm with at least 3 cm between each field using a prefabricated flexible template. In order to imitate skin lesions all fields were tape stripped 10 times with occlusive dressing before treatment (Tegaderm™ Roll, 3M, Glostrup, Denmark).

(37) On the left forearm vehicle Unguentum M was applied to the treatment field.

(38) On the right forearm excess amounts of 5-MAL 16% (Metvix®, Photocure, Oslo, Norway) were applied to all four fields of treatment. All fields were covered with light-impermeable, occlusive dressing. After 20 minutes the dressing was removed from the first field and the excess cream gently wiped off. The field was covered again with a thin piece of gauze and light impermeable dressing. After additional 20 and 40 min same procedure was followed with the second and third field. 180 min after application of 5-MAL and vehicle was removed from all five fields, and the excess cream was gently wiped of the last field. All fields were illuminated with red light. Illumination was performed with red LED light 630 nm peak (Aktilite™ 128; Photocure ASA, Oslo Norway) using a total light dose of 37 J/cm.sup.2 given over 9 min. During and after illumination pain was recorded. The volunteers were equipped with a special diary for recording pain in the days after treatment. Four follow-up visits were performed at day 1, 2, 3 and 8 after treatment.

(39) PpIX Fluorescence

(40) 5-MAL-induced PpIX fluorescence was depicted non-invasively using a fluorescence camera (Medeikonos AB, Gothenburg, Sweden). The amount of PpIX fluorescence was calculated from the photographs by the program MatLab® (MatLab®, MathWorks, Natic, US). The amount of fluorescence was measured before tape stripping and cream application (baseline) and before and after illumination.

(41) The photo bleaching is then the difference in PpIX fluorescence (AU) calculated from the pre and post illumination images.

(42) Erythema and Pigmentation

(43) As an indicator of inflammation erythema was measured. The erythema was assessed by an expert evaluator and measured objectively.

(44) The objective measurements of erythema and pigmentation were performed using a skin reflectance meter (Optimize Scientific 558, Chromo-Light, Espergaerde, Denmark).

(45) Erythema % and pigmentation % were measured before treatment, immediately before illumination, immediately after illumination, and at the four follow-up visits.

(46) Pain Score

(47) The volunteers scored their pain every minute during illumination, and recorded their pain in the diary every hour after illumination on the treatment day, twice per day the next three days and once a day on the following five days. Since PDT was performed at different times of the day the number of evaluations differed from 3 to 11 the first day. Pain was assessed using a numerical scale ranging from 0 to 10, where 0 is no pain and 10 is worst imaginable pain. To make it easier for the patients to identify the different treated fields, the dairy was supplied with numbered drawings of the fields.

(48) Randomizing

(49) The study was designed as an open randomised trial. A statistical adviser made the randomisation. Since the sequence of treatment duration was predefined, randomization was only determining which of the four treatment fields should be the first.

(50) Statistics

(51) The sample size was calculated on the bases of data from the literature. We set the minimal clinical relevant difference to 8.8% (50% of the earlier found 17.6%) and choose a power of 0.80 and a significance level of 0.05, 22 volunteers should be included.

(52) To identify differences in pain score, erythema % and pigmentation % between the treatment fields we used Wilcoxon Signed Ranked Test, since all results were paired.

(53) For all calculations a p-value<0.05 was considered statistical significant. All analyses were performed with PASW Statistics 19.0 for Windows (SPSS Inc, Chicago, Ill., USA).