In September 2008, the Committee for Medicinal Products for Human Use (CHMP) recommended European licensing approval of olanzapine long-acting injection for the maintenance treatment of adult patients with schizophrenia sufficiently stabilised during acute treatment with oral olanzapine. Final approval is usually granted within two to three months of the recommendation.
The benefits of the formulation were found to be:
- Its superiority over placebo in the treatment of schizophrenia as demonstrated in an 8-week, randomised, placebo-controlled superiority study that assessed changes in the Positive and Negative Syndrome Scale (PANSS) total scores.
- Non-inferior efficacy as compared with oral olanzapine in terms of exacerbation rates after 24 weeks.
The safety profile is similar to that for oral olanzapine with the exception of injection-related events. These include injection site pain, which occurs in about 5.5% of cases, and post-injection syndrome caused by inadvertent intravenous injection. The signs and symptoms of this syndrome are consistent with olanzapine overdose. Most patients develop sedation (ranging from mild in severity up to coma) and/or delirium. Other symptoms include extrapyramidal symptoms, ataxia and aggression.
Post-injection syndrome has been observed in 0.07% of injections and approximately 1.4% of patients. In most cases the initial signs and symptoms have appeared within 1 hour following injection and a complete recovery was reported to have occurred in all cases within 24–72 hours after the injection.
According to a Lilly Press release, a risk-management plan is to be put in place to identify and manage the post-injection syndrome. It will include a defined post-injection observation period and an extensive healthcare professional training and educational programme.
Use of this product may be limited by the need for patients to be observed for a set time after the injection has been administered. An observation period of three hours in a healthcare setting is likely to be required.  This formulation may be an option for a patient who has already responded to oral olanzapine, but for whom adherence is difficult. However, impact on the NHS may be limited.
More details on the clinical experience to date with olanzapine long-acting injection can be found in a recent review article.  General information on the treatment of schizophrenia can be found on the mental health section of NPC.