There is a considerable commercial opportunity for developers of antipsychotic drugs, according to market analysts Datamonitor, which claims that this class of drugs dominates the US market and boasted a global value of approximately $22 billion in 2008. Further growth is expected thanks to a pipeline of novel and reformulated atypical antipsychotics, but company success will be driven by experience as well as product innovation.

Success is expected for Johnson & Johnson's Invega Sustenna, a follow on to the company's Risperdal Consta formulation, which is delivered as an intramuscular injection. The new product is a ready-to-use formulation and offers an improved dosing regime.

"Invega Sustenna delivers uninterrupted compliance to patients and will provide an alternative to the long-established brands such as Zyprexa (Eli Lilly), Seroquel (AstraZeneca) or Risperdal to become the next multibillion dollar antipsychotic," Trung Huynh, a central nervous system analyst at Datamonitor, explained in a statement released by the firm.

Meanwhile, Schering-Plough has recently received FDA backing for Saphris for schizophrenia and bipolar disorder — the backing for bipolar disorder is especially significant because it has a larger market by patient number prescribing than schizophrenia. According to Datamonitor, sales in bipolar disorder will be "critical" to the drug's success. "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 favourable side-effect profile, Saphris has only comparable efficacy and a similar mechanism of action to that of existing brands," said Huynh.

In the case of Johnson & Johnson, it's not only innovation that will help the product's success; the company also has the necessary experience and network to launch the product. According to Huynh, smaller firms may not be so fortunate. "Small to mid-sized pharma that lack experience and funds will struggle to launch their drugs without an experienced partner in this competitive market; a factor that will severely limit penetration if their respective drugs eventually reach the market," said Huynh.

Undifferentiated oral products will also struggle to compete against the leading brands, but Datamonitor believes that, in the current antipsychotic drug market, capturing just 5% by becoming the second- or third-line alternative will still earn blockbuster revenues. The press statement from Datamonitor said: "Ultimately, the challenge for pipeline developers is innovation in terms of efficacy, tolerability and compliance, which will convince psychiatrists to prescribe new antipsychotics instead of established brands they are familiar with in the near term, and generic versions of these brands from 2012 onwards."

www.datamonitor.com