Evidence suggests that patients who switch from an originator biologic to open-label treatment with its biosimilar have an increase in subjective but not objective assessments and also discontinue the drug at a high rate, possibly reflecting a “nocebo” response to switching.

This finding from a multicenter, prospective study of 192 Dutch patients with rheumatoid arthritis, psoriatic arthritis, or ankylosing spondylitis who switched from infliximab (Remicade) to biosimilar infliximab ( CT-P13 ) led first author Lieke Tweehuysen, MD, of the St. Maarten Clinic in Nijmegen, the Netherlands, and her colleagues to speculate that the high discontinuation rate of nearly 25% of patients (n = 47) within the first 6 months of the switch may be because both the patients and their clinicians were aware that they were switching to the infliximab biosimilar (Arthritis Rheumatol. 2017 Oct 18. doi: 10.1002/art.40324).

If patients’ own negative expectations induced “negative symptoms (hyperalgesia or adverse events) during treatment, the so-called nocebo response,” and was the main contributing factor to the high discontinuation rate, then it will be very important for clinicians to improve communication with patients and their expectations in order to raise acceptance and persistence rates, the investigators said.

Of the 47 patients who discontinued CT-P13, 26 did so because of a perceived lack of effect, 11 because of adverse events, and 10 because of a combination of both of these factors.

Univariate Cox regression analyses showed that shorter infliximab infusion interval, higher 28-joint Disease Activity Scores (DAS28, based on either C-reactive protein [CRP] or erythrocyte sedimentation rate), higher swollen joint count, and patients’ global disease activity score at baseline were associated with CT-P13 discontinuation.

However, patients’ and clinicians’ awareness of the switch could have influenced these factors, the investigators said. For instance, they found that patients who discontinued CT-P13 reported a significant increase in “subjective” assessments such as tender joint count and patient’s global disease activity but not “objective” measures such as swollen joint count or CRP.

While the mean Bath Ankylosing Spondylitis Disease Activity Index score increased from 3.8 to 4.3, the mean DAS28-CRP in rheumatoid arthritis and psoriatic arthritis patients remained stable at 2.2 from baseline to month 6; CRP and anti-infliximab antibody levels also did not change.

“If immunogenicity would have caused CT-P13 discontinuation, we would have expected to find more patients with objectively active disease and/or allergic reactions,” the study authors wrote.

Three of the authors reported receiving speaking and consultancy fees from several pharmaceutical companies. The study was not supported by an outside grant.