Conditions: Psoriasis
Keywords: tumor necrosis factor (TNF) inhibitor tumor necrosis factor (TNF) blockade Methotrexate treatment mechanism psoriasis
Allocation: RANDOMIZED | Intervention model: PARALLEL
Enrollment: 33
Healthy volunteers: no

Brief summary:
The objective of this study is to compare the mechanism of action between adalimumab and methotrexate in subjects with psoriasis.

Detailed description:
Both methotrexate and adalimumab are FDA-approved drugs for the treatment of moderate to severe psoriasis. The two treatments, methotrexate and adalimumab, both show efficacy for psoriasis, however their profiles differ. In the CHAMPION Study, more adalimumab-treated, moderate to severe psoriasis patients achieved a PASI 75 after 16 weeks compared to those treated with methotrexate (80% vs. 36%). The reason for this difference is poorly understood. No direct comparative mechanism of action studies in psoriasis patients between methotrexate and adalimumab (or any tumor necrosis factor blocker) has been reported.

With etanercept, another tumor necrosis factor blocker, the in vivo mechanism has been studied with some scientific rigor. These studies demonstrate that etanercept down regulates multiple pro-inflammatory pathways (as shown in Table 1 of the protocol).

To date, there are no similar studies with adalimumab or methotrexate.

In order to understand the molecular and cellular basis for the differential clinical efficacy of adalimumab and methotrexate, it is essential to compare their mechanisms of action in psoriatic plaques. Biopsies will be performed, and we will study biomarkers in this proposal with immunohistochemistry, real-time polymerase chain reaction, and gene arrays.

Arms:
arm 1: Dosing will be on day 1 and then weekly. For the injections, dosing will occur according to product recommendations. Patients will receive 80mg adalimumab (2 pre-filled syringes, each with 40mg) on day 1, and then 40mg on week 1 and then every 2 weeks (from week 1 through week 15). arm 2: Patients will be dosed according to the CHAMPION study in single weekly doses of methotrexate: 7.5mg at week 0, 10mg at week two, and 15mg at week 4 for all patients. For each subject if the PASI did not decrease by at least 50% from baseline (PASI-50) at week 8, dosing will be increased to 20mg per week; the dose will be maintained at 15mg per week if PASI-50 was achieved at week 8. If PASI-50 was not achieved at week 12, dosing will be increased to 25mg per week; the dose will be maintained at 20mg per week if the PASI-50 was achieved at week 12. All patients on methotrexate will also receive a dietary supplement of oral folate (5mg per week). Methotrexate-treated patients will then receive 16 weeks of adalimumab at the end of study.

Interventions: intervention 1: Methotrexate intervention 2: Adalimumab (Humira)
Intervention descriptions: intervention 1: 2 cohorts (Randomized 1:1 adalimumab:methotrexate). Subjects will receive treatment on Day 1 (baseline visit) and then weekly or every 2 weeks for 16 weeks.

Methotrexate-treated patients will then receive 16 weeks of adalimumab at the end of study. intervention 2: 2 cohorts (Randomized 1:1 adalimumab:methotrexate). Subjects will receive treatment on Day 1 (baseline visit) and then weekly or every 2 weeks for 16 weeks.

Protocol document: