BACKGROUND: Current field-directed treatments of actinic keratosis (AK), a 
pre-malignant condition, are often limited by severe local reactions and/or 
complex treatment. Tirbanibulin, a novel potent anti-proliferative synthetic 
agent that inhibits tubulin polymerization and Src kinase signalling, is being 
developed as a convenient, safe, and effective field treatment of actinic 
keratosis.
HYPOTHESIS: A short course of tirbanibulin ointment 1% safely reduces AK 
lesions.
METHODS: In the Phase 1 study, 4 treatment cohorts with forearm lesions received 
tirbanibulin ointment 1% over 25 or 100 cm2 once daily for 3 or 5 days and were 
evaluated through day 45. In the Phase 2 study, 2 treatment cohorts with face or 
scalp lesions received tirbanibulin ointment 1% once daily for 3 or 5 days over 
25 cm2 and were evaluated through day 57. Lesion reductions, clearance rates, 
safety, and pharmacokinetics were assessed.
RESULTS: Forearm AK lesions were reduced by day 45 in all Phase 1 cohorts 
(N=30). Complete AK clearance at day 57 for face/scalp AK lesions in Phase 2 
cohorts (N=168) was demonstrated in 43% and 32% of participants of the 5-day and 
3-day cohorts, respectively. Adverse reactions were mainly transient mild local 
erythema and flaking/scaling, pruritus, and pain. Tirbanibulin plasma 
concentrations were low or undetectable.
CONCLUSION: Tirbanibulin ointment 1% was well tolerated and active in AK 
reduction. Based on activity, the 5-day regimen was selected for Phase 3 
development. Clinicaltrials.gov: NCT02337205; NCT02838628 J Drugs Dermatol. 
2020;19(11):1093-1100. doi:10.36849/JDD.2020.5576THIS ARTICLE HAD BEEN MADE 
AVAILABLE FREE OF CHARGE. PLEASE SCROLL DOWN TO ACCESS THE FULL TEXT OF THIS 
ARTICLE WITHOUT LOGGING IN. NO PURCHASE NECESSARY. PLEASE CONTACT THE PUBLISHER 
WITH ANY QUESTIONS.