Chugai, the Japanese manufacturer and distributor of the Roche flu drug, today said that Japan will only receive six million Tamiflu treatment courses, half of the 12 million that has been supplied in previous years to protect against a pandemic. The vast drop in supply is predominantly down to a decision by the Japanese government earlier this year to officially recommend that the use of Tamiflu in teenage patients be avoided. This move was prompted by reports of abnormal behaviour and self harming in younger patients after taking the flu drug, including two cases in February this year in which teenage patients taking Tamiflu to treat influenza were said to have "fallen to their deaths." While both Roche and Chugai maintain that no causal relationship between taking Tamiflu and the alleged psychiatric adverse effects has been established, the drug's prescribing information was nonetheless amended to include a warning pertaining to "incidences of self-injury and delirium," seizure and confusion. Over the course of 2005, Roche said that it received reports of 103 psychological reports during treatment of influenza with Tamiflu, including five deaths. None of these, the company said, had been proven to be the result of Tamiflu, with cases of neuropsychiatric events in patients taking the drug still very rare based on usage. The Japanese Ministry of Health, Labour and Welfare (MHLW) made its recommendation to restrict Tamiflu use in teens in March this year, essentially knocking out 20 per cent of the flu patient population for Roche/Chugai. The decision has, of course, also had a knock-on effect for other age groups, with the prescription rate having "changed substantially" following the governmental recommendation. While Chugai will only proactively supply the country with six million treatment courses, the firm said today that it also plans to develop an additional supply plan in case demand exceeds the company's expectations. Although Japan has opted out of full scale adoption of Tamiflu to protect against influenza, the drug is still currently the only antiviral treatment strongly recommended by the World Health Organization for the treatment of patients infected with the avian flu virus, H5N1. Bulk orders and soaring demand for the high profile flu drug prompted Roche to hike up production capacity a few years ago, upping capacity 15 fold between 2004 and 2006. However, with demand dwindling and the 'imminent' flu pandemic yet to arrive, the company realised that production was well in excess of demand and earlier this year announced plans to scale back manufacturing in line with current demand. According to Roche's financial results published three weeks ago, Tamiflu sales for the third quarter had plummeted 60 per cent compared to the same period last year, thanks to completion of pandemic stockpiling orders and the lack of any significant new orders. Figures for the year-to-date were only down two per cent on last year, but weren't helped by the restrictions on the use of the drug in Japan and the country's mild flu season. Roche has forecast Q4 sales of the drug to be in the CHF150m - 250m ($130m - $217m) range.