Extracts of the South American fern Polypodium leucotomos (PLE) are a common ingredient in sun creams. The agent has immunomodulatory effects, can prevent DNA damage, and has been shown to boost innate DNA repair systems, which makes it an interesting candidate for treating actinic keratoses. But is topically and orally PLE able to reverse severe actinic damage? To answer this question, a study including 131 patients with severe signs of photoaging and at least 3 AKs lesions was performed1.
Patients were randomised into 3 treatment groups. The first received topical photoprotection with SPF of 100 or higher together with a topical PLE-preparation alone, the second group was treated in the same way plus the fern extract in an oral form once daily, and the third and control group only used the topical photoprotection. In case new AK lesions were noted, participants were permitted to undergo therapy, e.g. imiquimod or cryotherapy. At 12 months, skin changes were evaluated with reflectance confocal microscopy (RCM), and clinical changes by 2 different AKs specific scores and the appearance of new AK lesions or the need for specific Ak interventions.
Data from 116 participants showed distinct improvements in the AK Field Assessment Scale Area (AK-FAS), especially in the arm also treated with the oral fern preparation: it improved by 26% compared with a 4% improvement in participants on topical PLE only and a worsening by 13% in the control group. “It is interesting that the control group that was given only common advice had increased photodamage and an increased number of new AK lesions,” said Dr Stefania Guida (La Sapienza University, Rome) who presented the study results. In contrast, there were no new lesions in both PLE groups. Participants in both intervention groups improved in the Actinic Keratosis Area Score Index (AKASI) score by 7%, whereas there was a deterioration by 6% in the placebo arm (P< 0.001).
RCM supported this clinical data: 51% of those receiving the oral and local preparation of PLE and 45% of those receiving the local PLE preparation only had normalisation of the honeycomb pattern compared with 26% in the control group (P = 0.04 for both comparisons). Also measured was a difference in the percentage of participants that needed additional therapy due to the occurrence of new lesions, which was necessary in 2% of participants taking both the oral and topical PLE preparation, in 11% of those only taking the topical PLE preparation, and in 38% of controls.