In people with chronic plaque psoriasis, combination therapy with low dose methotrexate should be considered when initiating adalimumab therapy.

A randomized controlled trial was carried out to determine safety, immunogenicity, effectiveness, and pharmacokinetics of adalimumab in combination with methotrexate in comparison with adalimumab monotherapy in psoriasis.

This single-blinded study included 66 people suffering from psoriasis. Participants were randomized to get adalimumab with methotrexate (ADL-MTX group, n=33) and adalimumab monotherapy (ADL group, n=33). Adalimumab drug survival at the final first-year study visit (week 49) was the major outcome ascertained.

The mean alteration in Psoriasis Area and Severity Index (PASI), percentage of people attaining PASI 75 and PASI 90, percentage of people attaining investigator global assessment (IGA) 0/1, mean alteration in Dermatology Life Quality Index (DLQI) and Skindex-29 (all evaluated in week 49) were the secondary clinical outcomes ascertained.

In total, 31 people in ADL-MTX arm and 30 in ADL arm were analyzed. Following 1 year, a non-significant better drug survival was reported in ADL-MTX group. Fewer people demonstrated adalimumab antidrug antibody in the ADL-MTX group. At week 49, the PASI 75 response, and the median (interquartile range, IQR) serum trough concentrations in the study groups, are shown in Table 1:

There were no serious adverse events. Patient reported outcomes (quality of life and effectiveness), and adverse events were similar between the study groups.

Compared to adalimumab monotherapy, the combination of MTX and adalimumab leads to fewer people showing adalimumab antidrug antibody, with a trend towards a better PASI 75 response, drug survival and increased serum trough concentrations.