The US Food and Drug Administration (FDA) has approved the expanded use area for Almirall’s drug Klisyri (tirbanibulin) to up to 100 cm² for the treatment of actinic keratosis (AK) on the face or scalp.

This approval extends the treatment area fourfold from the previous maximum of 25cm².

A microtubule inhibitor ointment, Klisyri is designed for use as a five-day topical field treatment for AK.

The supplemental new drug application approval was based on the findings from a multicentre, open-label, clinical safety Phase III study in more than 100 subjects in the US.

It aimed to assess the safety and tolerability of tirbanibulin when applied to a larger treatment area on the face or balding scalp of adult patients with AK as the primary endpoints.

The results of the study demonstrated consistency with the initial trials carried out on an area of 25cm², with similar outcomes for local skin reactions and treatment-related adverse events.

The effectiveness of tirbanibulin in the expanded area showed a comparable reduction in AK lesion count to that of the initial trials.

Klisyri will be offered in two package sizes to accommodate the different treatment areas: a 250mg package for up to 25 cm², and a new 350mg package for the expanded area of up to 100 cm².

AK, also known as solar keratosis, is a chronic and precancerous skin condition often found on sun-exposed areas of the skin.

Due to the potential for AK lesions to develop into squamous cell carcinoma, dermatological treatment is advised.

Almirall chief scientific officer Karl Ziegelbauer stated: “The FDA’s approval of the use of Klisyri for actinic keratosis on an extended surface of the face or scalp is a significant step forward for both patients and treating dermatologists.

“With patients experiencing AK over larger surface areas, dermatologists are looking for ways to treat the entire affected area to help prevent further lesion progression.”