Olanzapine in Chinese patients with schizophrenia or bipolar disorder: a systematic literature review

Abstract

BackgroundDespite the burden of schizophrenia and bipolar disorder in the Chinese population, country-specific data to guide practitioners regarding antipsychotic therapy are lacking. The primary aim of this systematic review was to examine evidence of the efficacy, effectiveness, and safety of olanzapine in Chinese populations.MethodsA systematic literature search was conducted using databases covering international and Chinese core journals using search terms related to schizophrenia and bipolar disorder, specified countries (People’s Republic of China, Hong Kong, Taiwan), and olanzapine treatment. Following initial screening, inclusion and exclusion criteria were applied to the search results to identify relevant studies from which data were extracted.ResultsA total of 489 publications were retrieved and 61 studies were identified for inclusion. Most studies were related to schizophrenia (n=54), with six studies related to bipolar disorder and one study related to both conditions. The quality of study methods and reporting in international journals was noticeably better than in Chinese language journals. Most studies included relatively small patient populations and were of short duration. The efficacy of olanzapine in Chinese populations was confirmed by multiple comparative and noncomparative studies that found statistically significant reductions in symptom measures in studies conducted for ≥6 weeks (schizophrenia) or ≥3 weeks (bipolar disorder). Findings related to effectiveness (treatment discontinuation, quality of life, and neurocognitive improvements) were generally consistent with those observed in non-Chinese populations. No new safety signals specific for Chinese populations were raised for olanzapine.ConclusionChinese and non-Chinese populations with schizophrenia or bipolar disorder treated with olanzapine display broadly similar responses. Differences between these populations, especially in relation to the relative efficacy of olanzapine versus other antipsychotics, may warrant further investigation via studies incorporating both populations. Use of local data to provide evidence for practice guidelines should be encouraged, and may promote ongoing improvements in the quality of research and study reporting.

Efficacy and safety of olanzapine for treatment of patients with bipolar depression: Chinese subpopulation analysis of a double-blind, randomized, placebo-controlled study

“…Further, the improvements with olanzapine treatment on key measures of depression such as MADRS, HAMD-17, and CGI-BP Depression were consistent with the findings of previous studies in patients with bipolar disorder 9,12,24. The safety profile of olanzapine in this subpopulation analysis was also consistent with that seen in the overall population and with the known safety profile of olanzapine, including data from studies in Chinese populations 13,15,24. These findings suggest the level of response to olanzapine in depressed Chinese patients with bipolar I disorder parallels that observed in non-Chinese patients.…”

“…A recent systematic review of the literature identified only seven studies, including four randomized controlled trials, that assessed the efficacy of olanzapine in Chinese populations with bipolar disorder 15. In terms of managing symptoms of mania, olanzapine has been shown to have similar efficacy to that of lithium in Chinese patients with bipolar disorder 15. In terms of managing depressive symptoms in Chinese patients with bipolar disorder, olanzapine appeared to be more effective than placebo but similar in efficacy to lithium 13,15.…”

“… 15 In terms of managing symptoms of mania, olanzapine has been shown to have similar efficacy to that of lithium in Chinese patients with bipolar disorder. 15 In terms of managing depressive symptoms in Chinese patients with bipolar disorder, olanzapine appeared to be more effective than placebo but similar in efficacy to lithium. 13 , 15 However, the evidence for the similar effect of olanzapine and placebo in managing depressive symptoms is derived from the international study by Tohen et al, 13 which included a mixed population in terms of race and ethnicity.…”

Switching to paliperidone extended release in patients with schizophrenia dissatisfied with previous olanzapine treatment

“…[16] Olanzapine, approved for the treatment of schizophrenia since 1998, is one of the most commonly used antipsychotic agents in China. [17] Although olanzapine has been shown to be effective in treating the positive and negative symptoms of schizophrenia, [18–20] earlier global studies have also reported undesirable metabolic effects with olanzapine. A pooled incidence of clinically significant weight gain (≥7%) was reported in 22% of patients on olanzapine, as reported in the US product label data of short-term treatment of generally 4 to 6 weeks.…”

Development of a population pharmacokinetic model of olanzapine for Chinese health volunteers and patients with schizophrenia

“… 2 In a study performed in China investigating 26 randomised controlled trials, a positive and negative syndrome scale assessment found a mean reduction value of 44.3 points with olanzapine treatment, suggesting that the drug has a positive effect for the treatment of schizophrenia. 3 The National Institutes of Mental Health-funded Clinical Antipsychotic Trials of Intervention Effectiveness study in the USA indicated that 74% of 1493 subjects terminated treatment with olanzapine within 18 months. The dropout rate among subjects who were first assigned to the olanzapine group was 68%, which was lower than the dropout rate for users of other atypical antipsychotic drugs, such as risperidone, quetiapine and ziprasidone.…”