A single‐center prospective observational study evaluating the efficacy and safety of tirbanibulin 1% in actinic keratoses in immunosuppressed patients: the ESTIMATE study

BACKGROUND: Actinic keratoses (AKs) are common precursors to squamous cell carcinoma and pose a heightened risk in immunosuppressed patients, such as organ transplant recipients (OTRs). PATIENTS AND METHODS: This prospective, monocentric, single-arm observational study investigated the safety and efficacy of topical tirbanibulin 1% ointment in treating Olsen grade 1 and 2 AKs on the face and scalp of 40 OTRs. At baseline (T0), demographic characteristics, clinical history, AKASI score, and AK count were collected. Patients applied tirbanibulin once daily for 5 consecutive days. Local skin reactions (LSRs) were evaluated on day 8 (T1), and efficacy outcomes - Actinic Keratosis Area and Severity Index (AKASI) and actinic keratosis count - were assessed on approximately day 60 (T2). RESULTS: All patients experienced mild or moderate local skin reactions (LSRs), primarily erythema and scaling, which resolved spontaneously without further intervention. By T2, the mean AKASI score decreased from 2.64 to 1.03, while the mean AK count dropped from 6.65 to 2.78; the differences were statistically significant. Notably, 52.5% of patients achieved at least 75% clearance, and 42.5% reached complete clearance. No serious adverse events or treatment discontinuations were reported. CONCLUSIONS: This study demonstrates that tirbanibulin is a safe, well-tolerated, and effective option for AK management in OTRs, addressing a critical need in this high-risk population.