Mufemilast (Heymay005) is a selective and orally active phosphodiesterase 4 (PDE4) inhibitor (IC50 = 80-120 nM) . Mufemilast modulates cytokines upregulated in Behςet’s syndrome (BS) . Mufemilast displays a significant inhibitory effect on TNF-α, which is an important proinflammatory cytokine target in the disease process of psoriasis. Mufemilast can be studied in research for diseases such as rheumatoid arthritis, psoriasis and BS[1][2][3][4][5].