Two Phase III Trials of KX2-391 in Actinic Keratosis Achieve Primary Endpoints

Two phase III studies—KX-AK-003 and KX-AK-004—achieved their primary endpoint of 100% clearance of actinic keratosis lesions at day 57 within the face or scalp treatment areas, with each study achieving statistical significance (P < .0001). Statistical significance (P < .001) was achieved for both face and scalp subgroups as well.

Actinic keratosis is a common skin condition that is induced through ultraviolet light damage, resulting in patches of thick, scaly, or crusty skin. Left untreated, the lesions have the risk of progression to squamous cell carcinoma. Actinic keratosis is the most common precancerous condition in dermatology and affects more than 55 million Americans.

KX2-391, also known as KX-01, is a first-in-class dual Src kinase and tubulin polymerization inhibitor being developed as a topical medicinal product (1% ointment) for the treatment of actinic keratosis in adult patients.

These two double-blind, randomized, vehicle-controlled, studies were designed as pivotal efficacy and safety studies to support the registration of KX2-391 as field therapy for actinic keratosis of the face and scalp. The studies, each conducted at 31 centers in the United States, enrolled a total of 702 subjects. KX2-391, or vehicle ointment, was applied once daily for 5 days. In addition to the clinical activity of KX2-391, the local skin reaction profile was within expectations, in line with the phase II study reported at the 2018 Annual Meeting of the American Academy of Dermatology.

Both studies are still ongoing to complete the 1-year follow-up of the patients who had complete responses.

More on Phase II Findings

The phase II clinical study (an open-label, multicenter study conducted in adults who had 4–8 actinic keratosis lesions within a 25 cm2 area on the face or scalp) was conducted in 16 U.S. clinical sites comparing 5 days vs 3 days of treatment (84 patients in each cohort).

The 5-day treatment cohort achieved a higher overall 100% clearance of actinic keratosis lesions at day 57 (ie, 8 weeks after the initiation of treatment) than the 3-day treatment cohort (43% vs 32%). In the 5-day treatment cohort, 23 of 44 subjects (52%) with actinic keratosis on the face, and 13 of 40 (33%), on the scalp, attained 100% clearance at day 57.

Local skin reactions, which were mild and mostly erythema, flaking/scaling, crusting, and swelling (with the majority of the local skin reaction scores of < 2), resolved rapidly.  

The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.




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