Rational :
Hyperpigmentation is a problem in all skin types. Safe depigmentation is a challenge. Cryotherapy with liquid nitrogen at -70 °C has been used in the treatment of solar skin lesions for many years but causes considerable damage.
Solar/senile lentigo is a harmless patch of darkened skin. It results from exposure to ultraviolet (UV) radiation, which causes local proliferation of melanocytes and accumulation of melanin within the skin cells (keratinocytes). Solar/senile lentigos or lentigines are very common, especially in people over the age of 40 years.
A solar/senile lentigo is a flat, well-circumscribed patch. It can be round, oval or irregular in shape. Colour varies from skin-coloured, tan to dark brown or black, and size varies from a few millimetres to several centimetres in diameter. They can be slightly scaly. Solar/senile lentigines are found as groups of similar lesions on sun-exposed sites, particularly the face or the back of hands.
Cryotherapy is more and more used to improve skin appearance and currently used to treat lentigo spot. However, the cryogenic gas (conventional cryotherapy - liquid nitrogen) creates a dermabrasion of the skin surface and person receiving this kind of treatment presents an impaired skin during a few days following the treatment as temporary damage of stratum corneum, erythema, scars, burns
Following the side effects occurring after conventional cryotherapy application, the Sponsor has developed some devices using difluoroethane, manufactured by CRYONOVE PHARMA, already available on the local and international markets, e.g. CRYOBEAUTY MAINS and CRYOBEAUTY CORPS.
To continue its research and development activities, the sponsor has selected a new sequence of a specific cryogenic spray which has been used effectively and safely for lentigos treatment in Fitzpatrick phototypes I to IV on the face, with benefit for the subjects without any adverse safety outcomes. There is therefore a need to test the devices for lentigo and PIH on darker skin phototypes (V and VI according to Fitzpatrick scale), which also encounter hyperpigmentation challenges.
In the study, the clinical evaluation of different criteria performed by a Dermatologist before and after treatment will lead to objectively assess the safety (outcomes) and efficacy (depigmenting) of concerned criteria.
Design:
The study performed is a proof of performance designed to be interventional, monocentric, randomized and double blinded.
Intervention :
1 prototype of devices is evaluated in 2 conditions. Each treatment corresponds to a combination of a specific sequence of a cryogenic spray and of a frequency of application
At least 80 spots will be randomized between the 2 conditions. Prototypes (816-v1 201) to (816-v1 290) will be applied on brown spots located on the face and/or the hands .
In condition 1, each spots will be treated 12 times by a defined prototype (always the same device on the same spot all along the study) and according to specific frequencies (every week).
In condition 2, each spots will be treated 6 times by a defined prototype (always the same device on the same spot all along the study) and according to specific frequencies (every two weeks).
Prior to any study device application, the dermatologist will assess the adverse events and will decide if the period between two consecutive applications should be extended or not.The dermatologist will verify that the skin has not been treated by cosmetic products (no presence of cream that could interfere with the treatment) and is dry.
As the study will use prototypes, before each treatment, the prototype will be administered to any surface (in order to purge eventually the presence of air). An operator previously trained by the dermatologist will apply the study device to the patient's face.
Subjects will be lying down, and the device will be administered upside down. During applications on the face, subjects will wear diving goggles protecting the eyes from cryogenic gas. For the application on the hands, the hands will be placed flat on the table and the prototypes will be applied upside down.
The patient follow-up visits are from Day 0 to 6 months.
