Role of MTX in addition to anti-TNF in PsA

In our last podcast we discussed the data for the use of methotrexate in psoriatic arthritis.

In rheumatoid arthritis, there is clearly benefit to adding methotrexate to anti-TNF therapy.

One question that was brought up was the role of methotrexate in addition to anti-TNF therapy in psoriatic arthritis.

On the Use of Concomitant Methotrexate With a Biological for the Treatment of Psoriatic Arthritis

Humira Prescribing Information

Responses were similar in patients who were or were not receiving concomitant MTX therapy at baseline.

Enbrel Prescribing Information

Responses were similar in patients who were or were not receiving concomitant MTX therapy at baseline.

Remicade Prescribing Information

REMICADE can be used with or without methotrexate.

This is markedly different than the information for rheumatoid arthritis that states "REMICADE should be given in combination with methotrexate."

Research Trials

Thus, 62.5% of infliximab patients also receiving MTX achieved an ACR20 response at week 16, as did 68% of infliximab patients not receiving MTX and 74% of those not receiving any DMARDs (P not significant).

Twenty eight of 47 (60%) patients receiving MTX at baseline (MTX users) and 30/53 (57%) patients not receiving MTX (MTX non-users) achieved an ACR20 response at week 14. Fewer MTX users than MTX non-users achieved an ACR50 response (28% v 43%) and ACR70 response (9% v 21%) at week 14. Results at week 24 were similar between MTX users and non-users for ACR20 response (57% v 51%), ACR50 response (43% v 40%), and ACR70 response (21% v 32%). The generally lower ACR50 and ACR70 responses among MTX users are probably related to the small number of patients included in these analyses and should be interpreted with caution. In general, the concomitant use of MTX did not appear to affect efficacy among patients in the infliximab group.

ACR20, ACR50, and ACR70 response rates did not differ between patients taking adalimumab in combination with MTX and patients taking adalimumab alone.

Thus, adalimumab appeared to be efficacious through week 48 for the treatment of the arthritis and skin disease of PsA, whether or not patients were receiving MTX at baseline. For adalimumab-treated patients, ACR and PASI re- sponse rates at week 48 were numerically greater in the with-MTX subgroups, but a significant difference (P < 0.05) between the with-MTX and without-MTX sub- groups was observed only for the PASI50 results.

Only 25% of participants in this trial received concomitant methotrexate treatment; the mean dosage was 12.7 (SD 4.3) mg/week. In this subset of participants, some benefit of combination therapy was apparent at week 12 for skin but not joint symptoms and only in those who received etanercept 50 mg twice weekly during this period.

We found similar responses to TNFi in patients with and without concomitant MTX, but drug survival was superior in patients receiving co-medication. The effect of MTX on drug survival was most prominent in patients receiving IFX.