The Food and Drug Administration (FDA) has accepted for filing the New Drug Application (NDA) for tirbanibulin ointment (formerly known as KX2-391 or KX-01 ointment; Athenex) for the treatment of actinic keratosis (AK).

Tirbanibulin is a first-in-class dual Src Kinase and tubulin polymerization inhibitor that works to upregulate apoptosis in proliferating cells. The application was based on data from 2 multicenter, randomized, double-blind, phase 3 trials (AK003 [N=351] and AK004 [N=351]) that compared the efficacy and safety of tirbanibulin ointment with placebo in adults with AK on the face or scalp. The primary end point for both studies was the proportion of patients achieving complete clearance of all AK at day 57. A key secondary end point was partial response at day 57, defined as ≥75% clearance of AK lesions.

Results from both studies showed that tirbanibulin-treated patients met the primary end point, achieving statistically significant clearance of AK lesions at Day 57. In AK003, 44% of patients treated with tirbanibulin achieved complete clearance compared with 5% in the placebo group (P <.0001). In AK004, complete clearance was observed in 54% of patients treated with tirbanibulin compared with 13% in the placebo group (P <.0001). Moreover, tirbanibulin was associated with a significantly greater partial response in both AK003 (68% vs 16%; P <.0001) and AK004 (76% vs 20%; P <.0001) vs placebo.

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Regarding safety, tirbanibulin was well tolerated with mild to moderate treatment-related adverse events, such as pruritus or pain. 

A Prescription Drug User Fee Act (PDUFA) target date of December 30, 2020 has been set for this application.

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This article originally appeared on MPR