Pharmaxis shares plunge on new Bronchitol setback

Shares in Pharmaxis (ASX:PXS) lost nearly half their value after the company revealed its phase III trial of Bronchitol in bronchiectasis failed to meet its primary endpoint.

Bronchitol caused only an 8% reduction in pulmonary exacerbation rates compared to the control over a 12-month treatment period - below the threshold for statistical significance.

But the study did meet secondary endpoints including safety and tolerability, a delay in time to first exacerbation, improved quality of life and reduced days on antibiotics.

“It is disappointing not to have achieved the primary endpoint in this trial,” Pharmaxis CEO Gary Phillips said. “We will therefore not be proceeding immediately with a regulatory submission for bronchiectasis.”

But he added that the topline trial results suggest that Bronchitol could prove to be more effective in a subgroup of bronchiectasis patients, allowing the company to commercialise the drug for that group.

“A full analysis will take some time, but encouragingly, available data suggests that Bronchitol performs better in some patients with high disease burden. Bronchiectasis is a heterogeneous disease and ... it seems likely that a clinically meaningful subgroup of Bronchitol patients can be identified.”

Pharmaxis shares fell 45.4% as the market reacted to the bad news, to reach $0.172 as of around 1.30 pm on Wednesday.

Bronchitol is a proprietary formulation of mannitol administered as a dry powder. It is designed to hydrate the lungs and assist with lung clearance.

Pharmaxis is also seeking approval for Bronchitol as a cystic fibrosis treatment. But the US FDA last month knocked back the company’s New Drug Application, recommending that Pharmaxis conduct a new clinical trial.