Late last year, there were high hopes on Allergy Therapeutics' new version of ragweed allergy vaccine called Pollinex Quattro, which has entered the last stages of development. Unlike existing vaccine treatments which typically require between 16 and 50 injections, Quattro requires only four shots over three weeks. It's much more convenient, and thus a more welcome mode of treatment for those with pollen allergies (tree pollen, grass pollen or ragweed). Indeed, patients have been recruited and the trials have begun. So far, so good, until last month, one patient reported "a rare adverse event" and the clinical studies had been placed on hold by the United States Food and Drug Administration ('FDA') while the manufacturers investigates the issue.

So, although Pollinex Quattro is already being used in Europe, further safety studies will still have to be conducted and the date for launch of Ragweed in North America will be 12 months later than previously anticipated.