PHNA, Efficacy of Tretinoin Cream on Post-phototherapy Hyperpigmentation
Phase: NA
Conditions: Vitiligo
Sponsor: The Catholic University of Korea

Full study protocol and Statistical analysis plan 
 
Department of Dermatology, St. Vincent's Hospital, College of Medicine, The Catholic 
University of Korea 
 
NCT03933774 
January 2, 2020 
 
 

Study protocol: Adult patients aged ≥ 19 years with stable, non-segmental vitiligo 
symmetrically distributed over the face are enrolled. The stable vitiligo is defined as follows: 
the absence of progression for at least 6 months prior to enrollment, and the absence of 
Koebner’s phenomenon, trichromic lesion, or confetti-like depigmentation. The exclusion 
criteria are pregnancy, sensitive skin, or photosensitivity. Each side of the face will be 
randomly assigned to receive the topical tretinoin 0.05% (w/v) cream (tretinoin group) or 
moisturizer (control group) every night during the period of NBUVB phototherapy, which 
will be performed on the entire face twice weekly for 12 weeks. The initial dose is 100 
mJ/cm2 and is increased by 50 mJ/cm2 at each subsequent session until a pink erythema that 
does not persist for ≥24 h appear. Patients who complained of erythema or irritation are 
instructed to mix topical tretinoin with moisturizer in proportions to relieved their complaints. 
The primary outcome is the degree of hyperpigmentation (the change in the L*value 
[delta L*]) of the darkest spots on either side of the face, using a spectrophotometer at 
baseline and every month thereafter. The secondary outcome is the treatment response to 
phototherapy assessed by deriving the VESTA by reference value based on clinical 
photographs obtained at baseline and every month thereafter. All adverse events are recorded 
at each visit.  
Statistical analysis plan: The paired t-test will be used to compare the delta L*values of the 
two groups. The treatment response proportions will be compared using the McNemar test. All 
statistical analyses will be performed using R ver. 3.6.1 software (R Foundation for Statistical 
Computing, Vienna, Austria).