Tirbanibulin Safe, Effective for AK on Face, Scalp

February 11, 2021
Morgan Petronelli, Associate Editor

Topical microtubule inhibitor, tirbanibulin (Klisyri, Almirall), demonstrates positive results for treating actinic keratosis (AK) of the face and scalp, according recently published data from two phase 3 studies.

Almirall announced the publication of the results from its phase 3 studies evaluating tirbanibulin (Klisyri, Almirall) for the topical treatment of actinic keratosis (AK) in the New England Journal of Medicine (NEJM), according a press release from the company.1

Tirbanibulin, a novel microtubule inhibitor recently approved by the FDA for the topical treatment of AK on the face or scalp, was developed in collaboration with Almirall and Athenex, Inc. Beginning in December 2017, the strategic partnership between the two companies required Athenex to be responsible for conducting all preclinical and clinical studies of tirbanibulin in order to gain FDA approval, according to the press release.

“This important publication represents a significant achievement for Athenex and all of our colleagues who have worked to discover, develop, and bring Klisyri to market” said Johnson Lau, MD, CEO of Athenex, in the release. “We would like to wholeheartedly thank our clinical investigators and the patients who participated in these trials, which were critical in confirming the clinical efficacy and safety profile in order to obtain FDA approval of Klisyri.”

The recently published studies investigated the safety and efficacy of tirbanibulin ointment 1% (10 mg/g) in 702 adults with AK on the face or scalp in two double-blind, vehicle-controlled, multi-center, parallel-group, randomized clinical trials (KX01-AK-003 and KX01-AK-004). As one of the largest phase 3 clinical study programs ever conducted for a topical actinic keratosis treatment, study participants were randomly (1:1 ratio) given either tirbanibulin or vehicle, which was self-administered once daily for five consecutive days on 25 cm2 of the face or scalp.

Both studies met the primary endpoint of complete (100%) clearance of AK lesions by Day 57 within the face or scalp treatment areas. Notably, each study achieved a highly statistically significant result (p<0.0001).

Results of KX01-AK-003 demonstrated a complete clearance in 44% of tirbanibulin patients compared to 5% of patients treated with vehicle. Meanwhile, in the KX01-AK-004 study, 54% of tirbanibulin patients achieved complete clearance versus 13% vehicle.

Additionally, tirbanibulin achieved the secondary endpoint in both studies, which is defined as partial (≥75%) clearance of lesions (68% of tirbanibulin vs. 16% vehicle in KX01-AK-003, and 76% vs. 20% in KX01-AK-004). Again, results from both studies were highly statistically significant (p<0.0001).

“We are delighted by the publication of the phase 3 data for Klisyri in the NEJM, one of the most prestigious and rigorously peer-reviewed medical journals in the world,” said Volker Koscielny, MD, chief medical officer of Almirall. “The clinical trial data presented not only demonstrates significant efficacy, but importantly a proven tolerability and safety profile. Added to the short 5-day application period, we believe that Klisyri provides an important addition to the therapeutic armamentarium of US dermatologists in treating actinic keratosis.”

Safety data from both studies was also favorable, with mild-to-moderate local skin reactions occurring and resolving without intervention. They saw no patient withdrawals from the phase 3 studies due to treatment-related adverse events.

Patients with the maximal post-baseline grades for each local skin reaction greater than baseline (>10%) by treatment group (Klisyri vs. Vehicle) were: erythema: mild (22%, 28%), moderate (63%, 6%), severe (6%, 0%); flaking/scaling: mild (26%, 25%), moderate (47%, 9%), severe (9%, <1%); crusting: mild (30%, 9%), moderate (14%, 2%), severe (2%, 0%); swelling: mild (29%, 4%), moderate (9%, <1%), severe (<1%, 0%).

“In addition to robust efficacy data, tirbanibulin demonstrated a favorable safety profile. The most common (≥2%) adverse events were local skin reactions, including pruritus and pain, at the application site. No patients withdrew from the study due to treatment-related adverse events,” said Andrew Blauvelt, MD, MBA, president of Oregon Medical Research Center, and one of the lead study investigators.


1. Almirall. Almirall announces new england journal of medicine publication of phase iii data demonstrating efficacy and safety of klisyri®(Tirbanibulin). Accessed February 11, 2021. https://www.prnewswire.com/news-releases/almirall-announces-new-england-journal-of-medicine-publication-of-phase-iii-data-demonstrating-efficacy-and-safety-of-klisyri-tirbanibulin-301226367.html