Safety and tolerability of switching to asenapine from other antipsychotic agents: pooled results from two randomized multicenter trials in stable patients with persistent negative symptoms in schizophrenia

Background: In clinical practice, clinicians often need to switch antipsychotic medications in patients with schizophrenia to optimize treatment outcomes. Here, we describe the safety and tolerability of switching existing antipsychotic treatments to asenapine or olanzapine monotherapy using various switching regimens. Methods: Data were pooled from 949 patients in two 26-week randomized double-blind studies. Patients with persistent negative symptoms of schizophrenia, stable for at least 5 months prior to screening and 1 additional month before randomization, were randomized to and treated with either asenapine (n = 485) or olanzapine (n = 464), and were tapered off existing antipsychotic(s) at variable rates within 28 days. Results: Prior to randomization, most patients were treated with second-generation antipsychotics (SGAs) (asenapine: 79.6%; olanzapine: 78.2%) and first-generation antipsychotics (FGAs) (31.1%; 29.7%), while depot formulations were used by 12.4% and 11.4%, respectively. Median time to taper off previous antipsychotics was 7 days, with approximately 40% of patients abruptly discontinuing their previous medication. Similar percentages of patients in each group reported at least one adverse event (AE) (asenapine: 76.9%; olanzapine: 75.2%). The majority of AEs occurred within the first 28 days. The most frequently reported AEs were somnolence, insomnia, and headache. The incidence of AEs in patients switching from SGAs, FGAs, or depot medications was similar between asenapine and olanzapine (77.5% vs 74.6%, 75.5% vs 79.7%, 85.0% vs 86.8%, respectively). AEs were more frequent in subjects previously treated with two antipsychotics (asenapine: 79.4%; olanzapine: 83.9%) versus one antipsychotic (asenapine: 76.3%; olanzapine: 72.2%) in the switch period. Conclusion: The presented data from post hoc pooled analyses may provide practical guidance for physicians switching partially stabilized patients with schizophrenia and persistent negative symptoms to asenapine or olanzapine.