Pipeline antipsychotic drugs to drive next market evolution

Antipsychotic pipeline developers have been in the spotlight in recent weeks with the announcement of the US Food and Drug Administration's approval of Johnson & Johnson's Invega Sustenna (paliperidone palmitate), FDA panel backing for Schering-Plough's Saphris (asenapine) and the end of Lundbeck and Solvay's collaboration for development of bifeprunox. With a global value of around $22 billion in 2008 - and the leading drug class in the USA - the commercial opportunity for antipsychotics is considerable. According to independent market analyst Datamonitor, the novel and reformulated pipeline atypical antipsychotics will be the engine that drives the growth potential of this developed market forward.

Indication expansion propels growth

Since the introduction of clozapine, the first atypical antipsychotic to treat schizophrenia, the growth of this class has been rapid. Offering improved efficacy, tolerability and superior side effects profile compared to typical antipsychotics, the launch of atypical antipsychotics further evolved the treatment of schizophrenia. However, the real growth driver has been the breakdown of the 'stigma' of using antipsychotics and expansion into different indications such as schizoaffective disorder, anxiety and depression. The broad clinical profile of atypical antipsychotics allows them to target a spectrum of psychiatric indications, increasing access to a wider variety and larger number of patients and therefore driving sales prescriptions and revenues. Pursuing indication expansion, AstraZeneca's Seroquel (quetiapine) and Eli Lilly's Zyprexa (olanzapine) became the biggest selling antipsychotics in 2008 with global sales of $5.5 billion and $5.4 billion, respectively.

Saphris' FDA advisory board backing for both schizophrenia and bipolar disorder is significant, as bipolar disorder is an even larger market by patient number prescribing than schizophrenia. Sales in bipolar disorder will be critical to the drug's success, says Datamonitor central nervous system analyst Trung Huynh. 'In this increasingly competitive environment, new market entrants need to stand out to make a significant impact on established brands and generic antipsychotics and despite a favorable side-effect profile, Saphris has only comparable efficacy and a similar mechanism of action to that of the existing brands,' he added. 'Datamonitor forecasts sales of around $600million by 2013, after which Saphris will be competing for prescriptions with generic versions of leading brands - Zyprexa and Seroquel,' he says.