Klisyri (tirbanibulin) is a novel microtubule inhibitor, recently approved by the U.S. Food and Drug Administration (FDA) for the topical treatment of AK of the face or scalp.

Almirall’s Klisyri (tirbanibulin) ointment demonstrated complete clearance of actinic keratosis (AK) lesions at day 57 in treated face or scalp areas in a significantly higher number of patients than vehicle, according to Phase III trials.

What’s more, Klisyri is safe with no patient withdrawals from the Phase III studies due to treatment-related adverse events. The new findings appear in the New England Journal of Medicine.

Klisyri (tirbanibulin) is a novel microtubule inhibitor, recently approved by the U.S. Food and Drug Administration (FDA) for the topical treatment of AK of the face or scalp.

"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," says Volker Koscielny, MD, Chief Medical Officer of Almirall, in a news release.

The Phase III studies evaluated the efficacy and safety of Klisyri (tirbanibulin) ointment 1% (10 mg/g) in adults with AK on the face or scalp and included 702 patients across 62 sites in the United States. Enrollment across patients was controlled to achieve a 2:1 ratio of facial to scalp treatment areas encompassing 4-8 typical AK lesions. Patients were randomly assigned in a 1:1 ratio to receive Klisyri ointment or vehicle ointment which was self-administered to 25 cm2 of the face or scalp once daily for five consecutive days.

Both Phase III studies, KX01-AK-003 and KX01-AK-004, met the primary endpoint, which was defined as complete (100%) clearance of AK lesions at Day 57 within the face or scalp treatment areas, each study achieving a highly statistically significant result (p<0.0001). 

In the KX01-AK-003 study, complete clearance was observed in 44 percent of the patients treated with Klisyri versus 5 percent for those treated with vehicle, and in the KX01-AK-004 study, complete clearance was observed in 54 percent of the patients treated with Klisyri versus 13% for vehicle. Furthermore, tirbanibulin also achieved the secondary endpoint of partial (≥75%) clearance of lesions in each study (68% of patients receiving tirbanibulin versus 16% receiving vehicle in study KX01-AK-003, and 76% versus 20% respectively in study KX01-AK-004). Both results were again highly statistically significant (p<0.0001). 

"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," adds Andrew Blauvelt, MD, MBA, President of Oregon Medical Research Center, and one of the lead investigators of the studies.

Local skin reactions were mostly mild-to-moderate in nature and resolved without intervention. The percentages of subjects 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%). 

"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," says Johnson Lau, MD, CEO of Athenex. "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.” Athenex conducted all preclinical and clinical studies to gain FDA approval of tirbanibulin.