Light emitting fabrics for PDT: technology and results of clinical studies

A homogeneous and reproducible fluence rate delivery during clinical PDT plays a determinant role in preventing underor overtreatment. In Dermatology, topical PDT has been carried out with a wide variety of light sources delivering a broad range of light doses. However, these light sources do not deliver a uniform light distribution on the skin due to their structure and morphology and the complexities of the human anatomy. The development of a flexible light source able to generate uniform light on all its surface would considerably improve the homogeneity of light delivery. The integration of plastic optical fibers (POF) into textile structures offers an interesting alternative. The homogeneous light side-emission from the fabric is obtained by controlling the bending angles of POF inside the LEF due to specific architecture generated by knitting of textile structure. LEF of different surfaces can be easily manufactured (up to 500cm² The LEF thickness is less than 1 mm. The mean irradiance is typically 2.5 mW.cm^-2. W-1 with heterogeneity of 12.5% at any point of the LEF. The temperature elevation remains below 1°C. These LEF were evaluated in Dermatology for the treatment of Actinic Keratosis. Two clinical evaluation were performed. The first one was a monocentric, randomized, controlled, phase II clinical study (ClinicalTrials.gov Identifier: NCT03076918). Twenty five (25) patients with grade I-II actinic keratosis (AK) of the forehead and scalp were treated with methyl aminolevulinate photodynamic therapy in two symmetrical areas. One area was treated with the conventional LED panel (154 AK), whereas the other area was treated with the LEF device (156 AK). The second clinical was performed in 2 centers. This new LEF device was a more ergonomic and compact version of the original system developed for FLEXIPDT. In this clinical study (ClinicalTrials.gov Identifier: NCT03076892), the irradiance has been reduced from 12.3 mW/cm² to 1.3 mW/cm² and the light dose from 37 J/cm² to 12 J/cm² . Compared to Conventional PDT, the 2 protocols clearly shown that LEF are equivalent and even superior in terms of efficacy for treating AK of the forehead and scalp. However, the use of LEF resulted in much lower pain scores and fewer adverse effects. In conclusion, thanks to LEF, PDT of AK can be conducted in all weather conditions, in any geographic location, year-round and benefits from the optimal adaptability of the flexible, light-emitting, fabrics to the treatment area. At last, LEF can be easily can be easily manufactured in large series.