Methods for the treatment of psoriatic arthritis using apremilast

A method of treating psoriatic arthritis, which comprises orally administering to a patient having psoriatic arthritis escalating doses of stereomerically pure (+)-2-[1-(3-ethoxy-4-methoxyphenyl)-2-methylsulfonylethyl]-4-acetylaminoisoindoline-1,3-dione, or a pharmaceutically acceptable polymorph, salt or solvate thereof, wherein the method consists of the following dosing schedule:

• (i) 10 mg in the morning on the first day of administration;
• (ii) 10 mg in the morning and 10 mg after noon on the second day of administration;
• (iii) 10 mg in the morning and 20 mg after noon on the third day of administration;
• (iv) 20 mg in the morning and 20 mg after noon on the fourth day of administration;
• (v) 20 mg in the morning and 30 mg after noon on the fifth day of administration;
• and
• (vi) 30 mg in the morning and 30 mg after noon on the sixth and every subsequent day of administration.