Prolonged-release schizophrenia drug gets EU approval

The new drug is a formulation of paliperidone, a derivative of risperidone - the active ingredient in J&J's leading schizophrenia drug Risperdal, which brought in $4.2bn (€3.1bn) in sales over 2006.

The new Invega product is formulated using OROS oral delivery technology, created by a fellow J&J subsidiary, ALZA.

The technology makes use of osmosis to achieve precise, controlled drug delivery for up to 24 hours, and can be used with a range of compounds including those that are poorly-or highly soluble and liquid formulations.

According to ALZA, the technology can be used to deliver high drug doses meeting high drug-loading requirements, and can result in enhanced bioavailability, reduced variability and can be adapted to provide patterned drug delivery.

Invega is the first and only treatment for schizophrenia to employ the osmotic delivery system, which delivers paliperidone in a consistent manner over 24 hours, resulting in smooth release of the drug through the day with minimal peaks and troughs in plasma concentrations.

The drug is also not extensively metabolised by the liver, according to the company, and is excreted largely unchanged through the kidneys.

This essentially means that it is not expected to cause any clinically significant drug-drug interactions with drugs metabolised by the liver.

According to the company the new drug provides strong efficacy, a proven safety and tolerability profile and improved patient functioning.

Invega was approved in the US at the end of last year, the first new prescription treatment or schizophrenia to be approved by the US Food and Drug Administration (FDA) since 2003.

The company carried out trials of the drug involving over 1,600 patients with acute schizophrenia in 23 countries, and performed particularly well on the 'Personal and Social Performance' (PSP) scale used to measure patients' ability to function in their daily life.

As a result, Invega prolonged-release tablets will be the first schizophrenia treatment approved in the EU to include improved social functioning in the product labelling.

Risperdal (risperidone), another Johnson & Johnson drug also marketed by Janssen-Cilag, is one of the company's leading products, approved by the FDA for the treatment of schizophrenia back in 19993.

However, despite showing healthy sales growth over 2006, the Risperdal compound patent is due to expire in the US in December this year.

The company has submitted paediatric data to the FDA in order to extend exclusivity through to June 2008, but the loss of the patent protection is likely to have a significant impact on sales and revenues as competing products enter the market.

The approvals for Invega, therefore, come at a good time, providing the company with a period of overlap for Invega to take root and help alleviate the hit the company's coffers could take when Risperdal loses that market exclusivity.

According to Johnson & Johnson, an even longer-acting version of Invega is not far behind.

The new treatment, containing paliperidone palmitate, will be administered by injection once every four weeks, with a new drug application for the product expected to be filed by the end of 2007.