**4.1 Medical follow-up**

280 Psoriasis

An interesting observation is the difference for the long-term result between complete and partial initial responders. Among complete initial responders, half patients maintain the response, and 21% have a complete relapse. In comparison, among partial initial responders,

We commonly propose infliximab in monotherapy. It is the most common method for treating plaque psoriasis, in contrast to other indications, where combination with methotrexate is systematic. The aim is therefore both to increase treatment efficacy, and to prevent the formation of neutralizing anti-drug antibodies (Poulhalon etal., 2007). The question of more frequently combining infliximab and methotrexate in dermatology has already been raised but never resolved. In our series, 4 patients take methotrexate in parallel with infliximab; they began it after around four months on infliximab, to compensate for insufficient efficacy. 1

In case of partial relapse, after removing the aggravating factors mentioned above, we usually suggest continuing treatment, this time in combination with methotrexate. The dosage of the latter is in line with usual regulations, adapted to the patient's weight (between 55 and 135 kg, for the present four patients). The medical practice is initially to diminish the dosage relative to methotrexate taken alone, but the clinical facts then dictate the procedure to follow. Tolerance posed no particular problems for three patients. The fourth patient experiences biological perturbations in the liver, which require frequent dose reductions; gastroenterology results are reassuring and allow treatment to be continued, which is furthermore essential due to the severity of the psoriasis and its impact on the

Another option would have been to adapt the dosage of infliximab; an increase in frequency has demonstrated success (an infusion every 6 weeks instead of every 8) (Duarte et al., 2011). In Belgium, this is impossible in common practice due to Social Security

If relapse is complete, a combination with methotrexate is not sufficient and the continuation of infliximab is not justified. It could even be deleterious, by analogy with other observations (Korswagen et al., 2011). Among patients with relapse (complete or partial, severe and resistant), 16 were treated with ustekinumab: after a minimum of 10 months, 5 responses at 100%, 7 satisfactory responses (50-99%), and 4 failures were observed. Please note: a naive patient of biological therapy for whom infliximab has never produced a significant improvement (primary non-responder), has then responded

The official dosage is 5 mg/kg, every eight weeks, after the induction phase. We adapted it in 8 cases. For 3 patients, we increased the frequency of infusions to 1x/6 weeks to try and

31% have a stable efficacy, and 50% have a complete relapse.

other patient began infliximab immediately in parallel with methotrexate.

We did not try to combine infliximab with other treatments for psoriasis.

**3.6 Infliximab and methotrexate** 

**3.7 Practical attitude in case of relapse** 

patient's life.

reimbursement regulations.

optimally to adalimumab.

**4. Adaptation of dosage** 

The medical follow-up we propose follows English guidelines (Smith et al., 2009): essentially clinical and anamnestic, it is also based on a blood sampling every six months and particular monitoring for tuberculosis risk. For our patients, we have not observed a tendency for weight gain or loss, nor change in blood pressure.
