OBJECTIVES : This study aims to review the HTA and regulatory bodies’ perspective on use of adherence evidence for second-generation antipsychotics (SGAs) in schizophrenia, and identify assessment gaps in decision-making.

METHODS : A total of 19 SGAs were selected including orals and long-acting injectables (LAIs). Of the 21 HTA agencies, 10 agencies had assessed at least one drug of interest. Of these, 7 HTA agencies that had reports available in English were further reviewed, including: the United Kingdom (NICE), Canada (CADTH), France (HAS), Germany (IQWiG), Australia (PBAC), Scotland (SMC), and Wales (AWMSG). Statistical Review document for the drug by FDA and the European Public Assessment Report (EPAR) were also reviewed.

RESULTS : Adherence is directly related to improved health outcomes of antipsychotics in schizophrenia. Both HTA and regulatory bodies consider adherence evidence for schizophrenia treatment submissions and appraisals. As part of literature search 43 documents were reviewed. PBAC and HAS had recommended all the assessed drugs and others had placed some of the SGAs in not recommended and restricted use category. Of the 7 HTA agencies, 3 did not report or critiqued regarding adherence data. The remaining 2 HTA agencies reported reduced frequency of drug dosing being a positive factor for adherence and one reported it to be missing data. Additionally, longer time to discontinuation was considered favorable implying good adherence. The evidence gaps identified were non-availability of: RWE for adherence, adherence scale reliability, comparison data of adherence between LAIs and oral SGAs, and injection site reactions and pain. Measures of adherence were not consistent across the 7 HTA agencies included.

CONCLUSIONS : Although most assessments critiqued about adherence evidence or lack thereof, none strongly recommended future RWE research or monitoring of adherence. Further research is needed to inform how adherence evidence can be incorporated in the assessment of schizophrenia treatments by HTA and regulatory bodies.