Lyophilised pharmaceutical formulation and its use

A pharmaceutical formulation in a lyophilised form, comprising unpegylated interferon beta-1a as an active ingredient in an amount of 2.0-15 μg in a single dosage form, a disaccharide as a bulking agent in an amount of 30-50 mg, and a non-ionic surfactant selected from the group consisting of polysorbate and polyethylene glycol, wherein the disaccharide is trehalose dihydrate or a mixture of trehalose dihydrate and sucrose, and wherein the interferon beta-1a is recombinantly produced interferon beta-1a with a biological activity higher than 150 Million International Units (MIU)/mg.