Evaluation of the effectiveness and safety of combined oral and topical photoprotection with a standardized extract of Polypodium leucotomos (Fernblock®) in a Moroccan population with xeroderma pigmentosum

Xeroderma pigmentosum (XP) is a rare autosomal-recessive genodermatosis resulting from a DNA-repair defect syndrome. The purpose was to evaluate the prevention on new malignant lesions in patients taking a supplement with Fernblock® (Polypodium leucotomos extract [PLE]) and secondarily correlation with the photoprotective behavior.A prospective, single-center and open cohort study was conducted over a 12-month period. The study was performed in Morocco. Optimal photoprotection behavior was recommended. Patients were instructed to take one capsule containing 480 mg of Fernblock® and 5 mcg vitamin D and to apply sunscreen with a SPF50+ and Fernblock® every 2 h during sun exposure. The demographic, clinical, and dermatoscopic patient data were collected at baseline (T0) and following visits at 3 months (T3), 6 months (T6), and 12 months (T12) when it was assessed: Investigator Global Assessment (IGA), Patient/Guardian Global Assessment (PGA), Patient/Guardian Satisfaction Questionnaire, and Photographic and Adverse Events Registration. Pertinent statistical study was performed.Eighteen patients completed the study. Eleven patients (61%) finished the study without new lesions. Seven patients developed new lesions by the end of the study. Among them, only 30% showed an ideal photoprotective behavior. The lack of an optimal photoprotective behavior increased the probability of developing lesions by 2.5 times with 95% confidence interval.In our study, more than 60% of patients taking a supplement with Fernblock® did not develop new lesions, and furthermore, we detected that patients following almost ideal photoprotection were 2.5 times less likely to develop NMSC lesions.