Background Biiosimilar TNF Mab (BioTNF) have become available in most of the European countries in the last few years. They are labeled to be used in the most common rheumatic diseases, like RA, AS and PsA. Controlled studies have shown comparable efficacy and safety of BioTNF and original TNF (Remicade, Enbrel). BioTNF are allowed to be used in TNF naive patients as well as in TNF pretreated patients (switchers). Prescriptions in different countries may vary due to local most often cost driven restrictions.

So far, little is known about the awareness, acceptance and possible obstacles which may influence patients willingness to accept therapy with BioTNF instead using the original compounds

Objectives The study was conducted and designed to get a deeper insight in what may influence patients decision making and willingness to accept treatment with BioTNF firsthand or accept switching.

Methods Between February 2015 and December 2016 41 patients (BioINF n=29, BioETA n=12) were introduced to BioTNF therapy. 9 Patients (Bio-INF n=3, Bio-ETA n=6) received TNF therapy the first time, in 32 patients (Remicade n=23, ETA n=8) werde switched from the originator TNF compound to BioTNF. All patients received comprrehensive information on BioTNF in verbal and written form.

A standardised questionaire was used to ask patients on their awareness, acceptance and about possible obstacles for the usage of BioiTNF Mab.

Results 6 out of 9 TNF naive patients agreed after their first information on BioTNF to start therapy with BioINF (n=3) or BioETA (n=3). Another 2 patients accepted BioETA therapy on their second visite. Only one patients asked to be started on the originator TNF Remicade. In patients being ask to switch from Remicade to BioINF 19 patients accepted promptly to be switch and in patients with Enbrel therapy 6 out of 9. Finally only 1 patient on Remicade TNF therapy denied even after a third visit to be switched. Mayor concern to deny the use of BioTNF were possible lack of efficacy (30%), safety (32%) and missing longterm experience (35%). The main motivation to switch was patients believe to save money and that they were ask to switch to BioTNF Mab on short notice from their health care insurance company.

Conclusions There is a high acceptance rate in patients with chronic inflammatory rheumatic disease to be started on or switched to BioTNF (>90%). Their are little concerns in patients accepting BioTNF with regard to safety or efficacy of BioTNF. Patients are aware of BioTNF as a less costly way to treat their rheumatic condition. Physicians should be aware of this willingness and offer BioTNF therapy were it is appropriate. Using BioTNF is a cost saving way to use biologics in rheumatic therapy with equal efficacy and safety compared to the originiator compounds.

Disclosure of Interest None declared