Mitigating the Nocebo Effect in Biosimilar Use and Switching: A Systematic Review.

Background: In the context of biosimilar use and switching, a patient's negative perception of a biosimilar might trigger a nocebo effect, where negative expectations unrelated to its pharmacologic action may lead to worsened symptoms, resulting in less perceived therapeutic benefit or worsened adverse events. Considering the crucial role biosimilars have in reducing health care costs and expanding access to safe biologics globally, it is essential to develop and implement effective strategies to mitigate the possible occurrence of such nocebo effects.

Objective: The aim of this systematic literature review was two-fold: (i) to review strategies that have been applied and/or tested for minimising the nocebo effect in clinical practice, within and outside the context of biosimilar switching, and (ii) to propose recommendations on useful mitigation strategies to minimise the occurrence of the nocebo effect in the context of biosimilar switching.

Methods: Biomedical databases PubMed and Embase were screened up until the end of April 2023 with a search string consisting of the following search terms "nocebo", "biosimilar", "mitigation", "strategy", and "prevention" and related synonyms. The search strategy was supplemented by snowballing of the included studies. The quality of the studies was assessed using the Joanna Briggs Institute Critical Appraisal Checklist for Systematic Reviews and Research Syntheses, the Scale for the Assessment of Narrative Review Articles, and the Mixed Methods Appraisal Tool.

Results: Of the 1617 identified and screened records, 60 met the inclusion criteria. Among these, 10 (17%) were conducted within the context of biosimilar switching, 7 of which specifically tested strategies to mitigate the nocebo effect. Among the remaining 50 studies conducted outside the biosimilar switching context, 46 tested mitigation strategies. Across the included studies, 13 distinct mitigation strategies were identified, which can be employed within the context of biosimilar switching: (i) open non-verbal communication, (ii) positive framing, (iii) empathic communication, (iv) validating communication, (v) shared decision making, (vi) self-affirmation, (vii) education of patients and health care professionals about the nocebo effect, (viii) education of patients and health care professionals about biosimilars, (ix) soft-skills training for health care professionals, (x) personalised information, (xi) supporting information, (xii) multidisciplinary approach, (xiii) organisation of the switch.

Conclusion: This review has identified a set of strategies that have been tested to mitigate the nocebo effect, which can be applied by health care professionals in the context of biosimilar switching with the aim of mitigating the occurrence of a nocebo effect. We recommend implementing a combination of mitigation strategies for patients and health care professionals to utilise before, during, and after a switch. It should be noted that given the limited number of studies specifically testing nocebo mitigation strategies within the biosimilar switching context to date, it is not yet possible to draw definite conclusions about the effect size of each mitigation strategy individually or in combination.