medwireNews: Co-medication with methotrexate may improve psoriatic arthritis remission rates for people initiating the tumor necrosis factor (TNF) inhibitors adalimumab or infliximab, but not etanercept, show data from a large, observational study in Europe.
Ulf Lindström (University of Gothenburg, Sweden) and colleagues say their “findings support the prevailing strategy, in a situation of incomplete response, to continue methotrexate therapy when commencing treatment with infliximab or adalimumab, while for etanercept methotrexate may be discontinued.”
The researchers carried out the study in order to address the current lack of international consensus regarding the optimal use of TNF inhibitors in people with psoriatic arthritis.
They reviewed data for 15,332 people from 13 European countries who initiated a first TNF inhibitor between 2006 and 2017. Of these, 62% were treated with TNF inhibitor and conventional DMARD co-medication and 38% received TNF inhibitor monotherapy, but proportions varied widely across the individual countries.
The investigators report in the Annals of the Rheumatic Diseases that individuals receiving co-medication were a significant 1.25 times more likely to be in clinical remission (DAS28-CRP <2.6 points) at 12 months than people only receiving a TNF inhibitor, after adjustment for age, sex, calendar year, disease duration, and DAS28 score.
When the team restricted the analysis to the most commonly used treatments, they found that people using methotrexate with adalimumab were a significant 1.45 times more likely to be in clinical remission at 12 months than those using adalimumab alone.
Similarly, methotrexate and infliximab co-medication was associated with a significant 1.55-fold higher likelihood of remission than infliximab monotherapy, but there was no such benefit to co-medication when etanercept was the TNF inhibitor of choice.
Lindström et al were unable, however, to measure the effect of co-medication on TNF inhibitor retention rates at 12 months, due to significant heterogeneity across the countries.
Indeed, the country-specific odds ratios for TNF inhibitor retention favored co-medication in eight countries (four statistically significant) and TNF inhibitor monotherapy in four countries (one statistically significant).
The authors comment that “in contrast to the relatively uniform results for the response rates, the pronounced intercountry differences in TNF [inhibitor] retention suggests that factors other than biological/pharmaceutical [efficacy] may have an influence on observed retention rates.”
They add that their “findings suggest that treatment retention should be analysed in a way that accounts for such factors, and that pooling of retention data across countries should be performed with caution.”
medwireNews is an independent medical news service provided by Springer Healthcare Ltd. © 2021 Springer Healthcare Ltd, part of the Springer Nature Group