**5. Clinical efficacy of methotrexate on psoriasis**

Even though MTX has been used extensively for the treatment of psoriasis, so far its efficacy has not been supported by any clinical datas. A non-randomized controlled trial study done by our research team showed PASI 75 was achieved in 75% of psoriasis patients after 7.5 mg of MTX orally per week for a period of 12 weeks. PASI 75 is defined as a reduction from baseline PASI score of >75%. PASI 75 is used as the benchmark of primary end points in assessing therapies for psoriasis. Patients reaching PASI 75 represent very meaningful changes in psoriasis severity [109–112]. A randomized controlled clinical trial using 15 mg of MTX for 16 weeks in moderate to severe plaque has showed 60% of patients achieved a PASI-75 response (no significant difference, *P* = 0.29), [113, 114]. For safety consideration, MTX has found to be administered along with 5 mg of folic acid to minimize the serious toxicity include hematological disorder, hepatotoxicity and gastrointestinal toxicity, MTX has also affect lymphocytes and also cause autoimmune reaction at extreme usage [115–117]. But, several studies has shown that 5–10 mg of MTX cause less side-effect on liver of

**Figure 6.** *Clinical efficacy of MTX on psoriatic patients.* *Immunomodulatory Effect of Methotrexate Abruptly Controls Keratinocyte Activation in Psoriasis DOI: http://dx.doi.org/10.5772/intechopen.102811*

psoriasis patients [118–121]. However more than 15 mg will cause severe side effects in psoriasis patients [121]. Clinical improvement of psoriatic patients before and after treatment of 7.5 mg of MTX per week for 12 weeks were depicted in (**Figure 6**).

Overall, the clinical data from our research study and also from other clinical trial has strongly supports that using low dose of MTX is well and safe for the treatment of moderate to severe psoriasis patients, and also frequent expert supervision along with laboratory monitoring is necessary.
