A pharmaceutical composition comprising cyclosporine A in liposomally solubilized form (L-CsA) for use in the prevention or treatment of a pulmonary disease or condition in a subject, wherein the pharmaceutical composition is administered to the subject by inhalation in form of an aerosol, and wherein the aerosol is generated by nebulization of the pharmaceutical composition using a nebulizer, the nebulizer comprising: a) an aerosol generator comprising: - a fluid reservoir for holding the pharmaceutical composition or an interface configured to connect a fluid reservoir, and - a vibratable membrane having a plurality of apertures, the apertures being adapted to produce an aerosol comprising droplets having a mass median aerodynamic diameter (MMAD) of up to about 4.0 μm as measured with a 0.9 % (w/v) aqueous solution of sodium chloride; b) a chamber for temporarily accommodating the aerosol generated by the aerosol generator, the chamber having an inner lumen with a volume in the range of from about 50 to about 150 ml; and c) a mouthpiece for delivering the aerosol supplied by the nebulizer to the subject, the mouthpiece having an exhalation filter; wherein the mouthpiece comprises: a body defining a fluid path from an inlet port connectable to the nebulizer to an inhalation opening to be received in the mouth of the user; and an exhalation filter having a filter base in fluid communication with the fluid path, a filter top detachably connected to the filter base and a filter material provided between the filter base and the filter top, wherein the filter top has an exhalation opening cooperating with a one-way valve allowing exhaustion of fluid from the fluid path through the filter material to the outside of the mouthpiece upon exhalation of a patient through the inhalation opening; wherein the body and the filter base are an integrated one-piece unit. wherein the pharmaceutical composition is administered to the subject by inhalation in form of an aerosol, and wherein the aerosol is generated by nebulization of the pharmaceutical composition using a nebulizer, the nebulizer comprising: a) an aerosol generator comprising: - a fluid reservoir for holding the pharmaceutical composition or an interface configured to connect a fluid reservoir, and - a vibratable membrane having a plurality of apertures, the apertures being adapted to produce an aerosol comprising droplets having a mass median aerodynamic diameter (MMAD) of up to about 4.0 μm as measured with a 0.9 % (w/v) aqueous solution of sodium chloride; b) a chamber for temporarily accommodating the aerosol generated by the aerosol generator, the chamber having an inner lumen with a volume in the range of from about 50 to about 150 ml; and c) a mouthpiece for delivering the aerosol supplied by the nebulizer to the subject, the mouthpiece having an exhalation filter; wherein the mouthpiece comprises: a body defining a fluid path from an inlet port connectable to the nebulizer to an inhalation opening to be received in the mouth of the user; and an exhalation filter having a filter base in fluid communication with the fluid path, a filter top detachably connected to the filter base and a filter material provided between the filter base and the filter top, wherein the filter top has an exhalation opening cooperating with a one-way valve allowing exhaustion of fluid from the fluid path through the filter material to the outside of the mouthpiece upon exhalation of a patient through the inhalation opening; wherein the body and the filter base are an integrated one-piece unit. a) an aerosol generator comprising: - a fluid reservoir for holding the pharmaceutical composition or an interface configured to connect a fluid reservoir, and - a vibratable membrane having a plurality of apertures, the apertures being adapted to produce an aerosol comprising droplets having a mass median aerodynamic diameter (MMAD) of up to about 4.0 μm as measured with a 0.9 % (w/v) aqueous solution of sodium chloride; - a fluid reservoir for holding the pharmaceutical composition or an interface configured to connect a fluid reservoir, and - a vibratable membrane having a plurality of apertures, the apertures being adapted to produce an aerosol comprising droplets having a mass median aerodynamic diameter (MMAD) of up to about 4.0 μm as measured with a 0.9 % (w/v) aqueous solution of sodium chloride; b) a chamber for temporarily accommodating the aerosol generated by the aerosol generator, the chamber having an inner lumen with a volume in the range of from about 50 to about 150 ml; and c) a mouthpiece for delivering the aerosol supplied by the nebulizer to the subject, the mouthpiece having an exhalation filter; a body defining a fluid path from an inlet port connectable to the nebulizer to an inhalation opening to be received in the mouth of the user; and an exhalation filter having a filter base in fluid communication with the fluid path, a filter top detachably connected to the filter base and a filter material provided between the filter base and the filter top, wherein the filter top has an exhalation opening cooperating with a one-way valve allowing exhaustion of fluid from the fluid path through the filter material to the outside of the mouthpiece upon exhalation of a patient through the inhalation opening; wherein the body and the filter base are an integrated one-piece unit.