Tirbanibulin 1% real‐world use in 679 actinic keratoses patients during warm season ( <scp>SUMM</scp> ‐ <scp>AK</scp> study)

Tirbanibulin 1% ointment is a topical field therapy approved for actinic keratoses (AKs) of the face and scalp, administered through a concise 5-day regimen with minimal local skin reactions (LSRs).1 Although field therapies are often deferred during warmer months, concerns regarding ultraviolet (UV) exposure and treatment tolerability lack systematic validation in real-world settings. We conducted a retrospective multicenter study across 33 dermatology units in Italy, including 679 adult patients treated with tirbanibulin between April and September 2024. The study aimed to evaluate efficacy, tolerability and patient acceptability under conditions of increased ambient UV exposure. Efficacy outcomes included clearance rates and the Actinic Keratosis Area and Severity Index (AKASI).2 The rationale for this investigation stemmed from current European recommendations supporting field-directed therapy and from the field-cancerization concept, which recognizes that lesion-targeted treatments may miss subclinical disease at risk of malignant transformation.3, 4 Managing AKs requires the balance of efficacy and tolerability, which becomes more challenging during summer months when higher UV exposure may exacerbate LSRs and reduce adherence.3, 4 Several topical AK therapies induce local inflammation, photosensitivity or irritation, limiting their applicability during sunny periods.5 Phase 3 clinical trials established tirbanibulin's efficacy and safety under controlled conditions,1 while independent real-world studies have confirmed significant reductions in AKASI scores and high patient acceptability.6-9 The feasibility of tirbanibulin treatment during warmer months is further supported by its lack of photoallergic or phototoxic potential.10 In our cohort, the mean patient age was 74.9 ± 9.7 years, with men representing 70.8% of cases and 77.6% reporting long-standing AK (>1 year). Lesions were predominantly located on the face (61.8%) and scalp (31.8%), with a smaller proportion affecting the upper chest and hands, confirming the treatment's versatility across sun-exposed areas. Adherence was complete (100%), suggesting that the short, well-tolerated regimen is easily manageable even under conditions of elevated temperature and UV exposure. Treatment outcomes were favourable (Figure 1a; Table 1). In our cohort 69.7% of patients attained at least a 75% reduction in lesion burden. The mean AKASI score decreased from 4.54 to 1.67 (Δ − 2.87; −63.2%, p < 0.001), and visible photodamage improved in 30.5% of cases. Because AKASI is a head-specific measure and can be influenced by untreated areas, complete clearance within the 25 cm2 treated zone may not correspond to an AKASI of 0.2 Tolerability remained favourable despite summer exposure (Figure 1b). Most LSRs were mild or moderate; grade ≥3 reactions occurred in 11.9% of patients, with no grade 4 events or treatment discontinuations. Erythema was the most frequent reaction, followed by scaling and crusting. Patient and clinician satisfaction were high, 79.4% and 83.1%, respectively, rated ≥3 out of 4; and satisfaction scores correlated positively with clinical response and inversely, though weakly, with LSR severity. These results, derived from the largest real-world series conducted during the warm season, are consistent with pivotal trials1 and independent studies demonstrating meaningful AKASI improvements and the practicality of the five-day regimen.6-8 The absence of photoallergic or phototoxic effects, coupled with a reassuring safety profile under maximal-use conditions, supports both the pharmacologic and biophysical rationale for summertime application.5-10 Limitations include the retrospective design, non-standardized follow-up and variable UV exposure. Nevertheless, the consistency of findings across endpoints reinforces their external validity. In conclusion, tirbanibulin 1% ointment represents an effective, well-tolerated and innovative field therapy for AK, with a short regimen that fosters adherence and maintains safety even during periods of high UV exposure. These results endorse tirbanibulin as a compelling therapeutic option throughout the year, including the warmer months. Future prospective studies should further refine follow-up protocols and evaluate the long-term durability of clinical response. None. M. Ardigò has received consulting fees from Pierre Fabre and has participated in lectures, presentations and advisory boards for Almirall, Kyowa Kirin, Pierre Fabre, Recordati Rare Diseases and Cantabria Labs. L. Atzori has participated in advisory boards, lectures, presentations and received support for attending meetings from AbbVie, Amgen, Sanofi, LEO Pharma, Pfizer, Eli Lilly, J&J, BMS, Novartis and UCB. R. Balestri has received support for attending meetings from Lilly, AbbVie, Amgen and Novartis. S. Barruscotti has participated in presentations/lectures for L'Oreal. M. Bruni has participated in presentations/lectures for Almirall, AbbVie and Novartis. S. Caccavale has received consulting fees from Boehringer Ingelheim, and has participated in lectures/presentations for AbbVie, Novartis, Pfizer, J&J, Almirall and LEO Pharma, and received support for attending meetings from Galderma and Eli Lilly. A. Carugno has received payment or honoraria for lectures/presentations from Almirall, UCB, J&J and Novartis, and has participated in advisory boards for Almirall, AbbVie, BMS, Sanofi, LEO Pharma, UCB and Boehringer Ingelheim; he has also received support for attending meetings from Almirall, Sanofi, AbbVie and Novartis. G. Ciccarese has received consulting fees from Almirall and support for attending meetings from Pierre Fabre. G. Dal Bello has participated in presentations/lectures for Almirall. P. Danese has received grants or contracts from Sanofi, LEO Pharma and Almirall and support for attending meetings from Sanofi, LEO Pharma, Almirall and AbbVie. L. Germi has received consulting fees from LEO Pharma and AbbVie and has participated in lectures and presentations for Novartis and advisory boards for AbbVie and Almirall. S. Giacalone has received payment or honoraria for lectures from LEO Pharma, AbbVie, Almirall, Sanofi, UCB and Novartis, and has participated in advisory boards for Almirall. R. Giuffrida has received payment or honoraria for lectures and presentations from Pierre Fabre. G. Nazzaro has received payment or honoraria for lectures from Novartis, Giuliani Pharma, L'Oreal, IDI Farmaceutici and Almirall. M. Valenti has received payment or honoraria for lectures and presentations from Sanofi, Sun Pharma, Almirall, AbbVie, Novartis, UCB, Boehringer Ingelheim, LEO Pharma, Eli Lilly, Difa Cooper and Janssen, support for attending meetings from Sanofi, Almirall, AbbVie, Novartis, Janssen, LEO Pharma, UCB and Eli Lilly, and has participated in advisory boards for Almirall and UCB. E. Zavattaro has received consulting fees from Active Pharma Group and support for attending meetings from the Ganassini Institute and Sanofi–Regeneron. All other authors declare no conflicts of interest. The commencement of the study was formally notified to the Institutional Ethics Committee of Varese (notification n° 82/2025). The study was conducted according to the ethical principles outlined in the Declaration of Helsinki and in compliance with applicable privacy regulations, including Regulation (EU) 2016/679 (GDPR). The patients in this manuscript have given written informed consent for the publication of their case details. The data that support the findings of this study are available from the corresponding author upon reasonable request.