The rejection of a Pharmaxis's new drug application for an asthma diagnosis product, Aridol, by the US Food and Drug Administration (FDA) had resulted in a severe decline of 6%this morning.

Shares of the Sydney-based biotechnology company have more than doubled this year, surpassing the 30 percent increase for the benchmark S&P/ASX 200 index.

However, the FDA's pulmonary-allergy drugs advisory committee voted to recommend approval for the drug in November and Aridol is approved for sale in Australia, Korea and major European countries.

Pharmaxis chief executive Alan Robertson said the letter and comments from the FDA provided disapproval for its lung-function test Aridol, giving a clear view of the regulator's requirements. Deficiencies at manufacturing and testing subcontractors, a labeling issue and post-marketing requirements are believed as the major reasons for the disapproval, Pharmaxis said. The company has said that it would work on the matters raised by FDA in their response.

The company claimed that Aridol is a lung function test to enable doctors to diagnose asthma by detecting the severity of a patient's inflammation, and accordingly prescribe the desired amount of medication for its control.