Pharmaceutical compositions and single unit dosage forms of apremilast, i.e., (+)-2-[1-(3- ethoxy-4-methoxyphenyl)-2-methylsulfonylethyl]-4-acetylaminoisoindoline- 1,3-dione, or a pharmaceutically acceptable stereoisomer, prodrug, salt, solvate, hydrate, or clathrate, are provided herein. Also provided are methods of treating, managing, or preventing various disorders, such as diseases or disorders ameliorated by the inhibition of TNF-a production in mammals. Examples of the diseases include: a viral, genetic, inflammatory, allergic or autoimmune disease.
