Swiss drugs major Roche has a 22-per cent increase in sales to $6 billion in the first quarter ended March 31, boosted by global demand for flu drug Tamiflu.

Sales of Tamiflu, being stockpiled by several countries as a precaution against any possible outbreak of bird flu, rose 37 per cent over the first quarter of last year with predictions of annual sales of Tamiflu reaching close to the billion-dollar mark in 2006.

Its cancer drugs, of which it is the leading global maker rose by 52 per cent year-on-year, led by demand for Avastin, effective in the treatment of colon, breast and lung cancers.

In December 2005 the New England Journal of Medicine, had suggested that the drug could become ineffective as the virus could develop more quickly than expected.