Treatment of Psoriasis by UVB is a common, effective and respected therapy for more than 100 years.[1] Narrow band UVB light (peak 296-313 nm) has been  clinically shown to be the  most effective regime for psoriasis therapy. [2,3]

 

Typical clearing regimen treatment with full body narrow band fluorescent bulbs (such as TL-01) employs a cumulative dose of   13J/cm2

(range 4 J/cm² -24 J/cm²)  exposing  both lesional  skin  and  non involved "normal"  skin to  UV. In  classical  full  body  narrow  band UVB therapy clearing is achieved in 80% of treated patients in

4 weeks, 3-4 treatments /week.  Fifty percent  of the 

responding  patients of patients remain clear after

6 months [4].

 

It is known that normal skin can be exposed

to up to 3 MEDs without blistering,  while psoriatic skin may be exposed to up 3 times this dose (9  MEDs) without blistering. [5,6] A therapy targeted only to psoriasis plaques sparing the “healthy” skin may thus employ higher fluences and may shorten time to clearance. Another advantage of targeted phototherapy is the sparing of non psoriatic skin from harmful UV effects.  Asawanonda et . al [6]  treated psoriasis with an  Excimer laser emitting 308nm . Fluences  of up to 6 MEDs on psoriasis plaques were well tolerated by all patients.  Most patients remained cleared after 2 months of follow-up.  Excimer  laser  therapy was  associated  with  a few mild  side  effects such  as temporary hyper-pigmentation, blistering- similar to a sunburn, 

erosions and possible  mild local  pain during therapy.  

 

Diericks  presented  her work  with a non coherent targeted UVB  phototherapy  system. This system  produced  high intensity UVB light  delivered  to the skin through  an optic fiber  to treat  a 16mmX16mm spot. In her study,  patients  with  multiple psoriatic plaques were treated   with  1,3,5, or 7X MED once per week for up to 15 weeks. Treatments  were  well tolerated  with only minor  adverse effects such as erythema transient  hyper pigmentation and  occasional blistering. Six out of ten patients  responded favorably to the treatment. Improvement  was noted  after one or two treatments . Plaques  were cleared  from most anatomical locations including the hands, elbows knees, trunk  back and buttocks.

 

The MultiClear™ is a novel tunable multiwavelentgh medical device which selectively targets a multitude of skin conditions. It emits high intensity incoherent light which is tunable  to a few optimal narrow band  emission spectra In the  UVA and  UVB range. Optimal treatment parameters are  selected  through  a fully  computerized built in  expert system.

 

This high intensity novel device may expose psoriatic skin to high narrow band fluences totally sparing the non lesional skin.  Basic  setup  provides  a spot size as large as 23X23 mm. Computerized  controls  allows  exposures  of up  to 7 MEDs  in both   continuous  or pulses mode.   UVB  emission  peak  at  304-313 nm  is optimized  to  fit best  efficacy /erythema  treatment  ratio.

 

Multicenter study:

 

A multicenter study utilized the MultiClear™ (Curelight Ltd.) operated with an enhanced plasma lamp mixture.  Spectral measurements indicated lack of emission  below  294  nm and a significant peak at the maximal efficacy wavelengths of 304 and 313nm. A specially designed light concentrator focuses the light on a liquid fiber allowing a homogenous  of 23X23mm effective  treatment  spot size.  

An  initial study included 10 patients with a variety of  plaques sizes. Patients  had  stable  psoriasis  and  have not used  any  topical  anti psoriatic  medications for  at  least 4  weeks  prior  to trial. Eighty  percent of  the patients responded  to the treatment with  minimal side effects.  . In responding  patients, 80% Clearance was  noted  after an  average  of  6   treatment sessions.  Dose  range  per lesion was  0.15-4 J/cm2.  Lengths of a full treatment  session/per patient   was  5-10 minutes.

 

 

 

Figure 1.  MultiClear therapeutic spectrum

 

    

 

Figure 2.  A.   Before therapy; female patients, 55 years olds, stable  psoriatic  plaque  on  Rt. Elbow. Psoriatic plaque prior to the first treatment.  B.  Same plaque 5 months  after  5  treatments.

 

 

Figure 3.  Female patient, 75 years old, stable  psoriatic  plaque  on the back. A. Before therapy.   B. After  2 weeks (4 treatments) C. After 5 weeks ( 8 treatments)  D. 3 months after last treatment.

 

 

Figure 4.  Female patients, 45 years old, stable  psoriatic  plaque  on the lower back. A/B Before therapy . C. After  3 weeks (5 treatments) C. 4 months after last treatment.

 

 

Summary:

 

Treatment of plaque psoriasis can be effectively and  safely achieved with narrow  band  UVB light (296-313 nm spectral band). Comparing  efficacy  to  the  different  UVB spectral peaks has  shown  the 304nm is  more  efficacious  for  plaque psoriasis  than  any other  single  UV  wavelengths.

 

The  MultiClear multiwavelentgh  targeted phototherapy  system tested  in the  current  study  allows  high  intensity  304, 313 nm optimized  UVB therapy  over  a large  23X23mm  spot size.,

Computer guided  MED  assessment  allows  an accurate  and  fast  MED assessment  crucial to  accurate starting  dose selection. Built  in  expert  system suggests  dose  increases based Modified   PASI  built in scoring. Treatment doses as high as 7 MEDs are used  on  psoriatic  lesions while  totally  sparing  non involved  skin . Our  preliminary  data  shows a  response  rate  of  80%   of  the patients psoriasis plaques with  average  clearing  after 6  biweekly  treatments as  compared  to usual 30-40  treatments  with  classical  full  body  UVB  systems 

The  MultiClear  targeted   phototherapy   provides  major  advantages   to  other  available  full body or targeted UVB modalities.  Accumulated  lesional   UV  doses till clearing  are  a  third  than accumulated  UV  doses  till clearing in classical  full  body  systems. (4J/cm²  vs. 13J/cm²). Most importantly the  MultiClear  targeted  phototherapy   totally  spares  non involved  skin  from  UV -  thus   providing  a superior  safety profile. Response is  achieved  in an average  of  6 biweekly  treatments (3  weeks)  instead  of  30-40  treatments in  full  body  light  boxes (8-10 weeks  of  3-4 treatments/weeks).   The faster   results  achieved with the  MultiClear (compared  to  excimer  laser  or  other non coherent  targeted phototherapy  systems)  may  be  explained  by  its  optimized   304nm UVB wavelength (308nm or  non  optimized  UVB in other  devices). It  may  be  also  due  to  better  and  easier   dosing  monitoring  through the  MultiClear  UV assessment  based   Dosing System (MUDS™). 

 

References: 

 

1.  Fischer T. UV-light treatment of psoriasis. Acta Derm Venereol (Stockh) 1976;56:473-9.

2.  Parrish JA, Jaenicke KF. Action spectrum for phototherapy of psoriasis. J Invest Dermatol 1981;76:359-62.

3.  313 as action spectrum for psoriasis.  Abel EA. Phototherapy. Dermatol Clin 1995;13:841-9.

4.  Green C, Lakshmipathi T et al. A comparison of the efficacy and relapse rates of narrowband UVB (TL-01) monotherapy vs. etretinate (re-TL-01) vs. etretinate-PUVA (re-PUVA) in the treatment of psoriasis patients. Br J Dermatol 1992 Jul;127(1):5-9

5. Bonis B, Kemeny L et al. 308 nm UVB excimer laser for psoriasis. Lancet 1997 Nov 22;350(9090):1522 .

6. Asawanonda P, Anderson RR, Chang Y, Taylor CR. 308-nm excimer laser for the treatment of psoriasis: a dose-response study. Arch Dermatol 2000 May;136(5):619-24.