No Tamiflu-suicide link yet, states EMEA

European drug regulators remain adamant that there is as yet no clear causal relationship between Roche's anti-flu drug, Tamiflu, and the alleged suicidal deaths of two adolescents in Japan.

However, concerns over potentially harmful psychiatric side effects linked to the use of Tamiflu continue to permeate global markets, whose governments are likely in the throes of stockpiling millions of doses in preparation for a feared flu pandemic.

It is no surprise for Roche or drug regulators that psychiatric side effects, such as delirium, disorientation and other abnormal behaviour, could be linked to Tamiflu, as there were ìalready some reports at the time of [European] approval in 2002,î a spokesman for the European Medicines Agency (EMEA) confirmed this week.

However, while the Japanese Health Ministry saw fit to issue an official warning of potential risks in June 2004, neither the EMEA nor the Food and Drug Administration (FDA) in the US - both of which saw the same pool of data, supplied by Roche, as Japan's authorities - have taken the same course of action.

ìThat said, we're not simply sitting by,î the EMEA told Pharmaceutical Marketing. ìIn August 2005 we wrote to Roche and asked them to continue monitoring closely all reports on Tamiflu-related psychiatric disorders, which the company has done since the product's launch in Europe in 2002.î

The regulator added that the suspected suicide deaths of the two Japanese men have not, according to official reports, been classified as suicides. ìThe adolescents were exhibiting abnormal behaviour, but the incidents are not being treated as suicide. It is very difficult to identify whether someone suffering from influenza has consciously committed suicide, or whether they were in a confused state and [in the case of one of the men] were hit by a vehicle.î

The risk of suicide or other serious psychiatric disturbances does not appear on the drug's labelling at present, yet the EMEA noted that, should the adverse reports reveal any convincing new evidence of such risks, it may well take further action.

ìIt could come from the data. What would need to happen is the establishment of the causal relationship; that has not yet been identified.î

In July this year, a full review of Tamiflu's safety was conducted by the European regulator, which found that half of all adverse event reports came from Japan and ìof 48 reports of serious psychiatric disorders, 28 came from Japan and 20 came from four other countriesî -?France, Germany, the US and Canada.

ìWe are unclear as to why there is this reporting imbalance,î said the EMEA spokesman. ìIt may be usage, it may be other factors. It is unclear.î

Neither Roche nor drug regulators have issued any extra warnings or messages regarding the stockpiling of Tamiflu by governments both inside and outside Europe, in anticipation of a major flu outbreak.

ìThe industry will continue to keep it under review, but at the moment there is no change,î commented the EMEA spokesman.