1. The use of adapalene or its pharmaceutically acceptable salt to obtain a pharmaceutical composition intended for administration in combination or for concomitant administration with benzoyl peroxide to reduce the number of acne lesions. The use according to claim 1, wherein the pharmaceutical composition is a fixed combination comprising, in a pharmaceutically acceptable medium, (i) at least one compound selected from adapalene and its pharmaceutically acceptable salts, and (ii) benzoyl peroxide. The use according to claim 1, wherein the acne lesions can be inflammatory or non-inflammatory lesions. The use according to claim 3, wherein the reduction in the number of inflammatory and / or non-inflammatory lesions of acne is at least about 40%, preferably at least about 50%, and more preferably at least about 60%. The use according to claim 2, in which adapalene and benzoyl peroxide are present in the pharmaceutical composition in synergistic amounts. The use of claim 2, wherein the pharmaceutical composition comprises 0.1% adapalene and 2.5% benzoyl peroxide. The use of claim 2, wherein the pharmaceutical composition is a gel. The use of claim 2, wherein the pharmaceutical composition is adapted for topical application. The use according to claim 1, wherein said pharmaceutical composition is in the form of a composition A containing adapalene intended to be applied together with a composition B containing benzoyl peroxide. The use according to claim 9, where adapalene and benzoyl peroxide are present in compositions A and B in synergistic amounts, respectively. The use of claim 9, wherein composition A contains 0.1% a�1. Применение адапалена или его фармацевтически приемлемой соли для получения фармацевтической композиции, предназначенной для введения в комбинации или для сопутствующего введения с пероксидом бензоила для уменьшения числа поражений акне.2. Применение по п.1, где фармацевтическая композиция является фиксированной комбинацией, содержащей, в фармацевт