Swiss pharma company Actelion saw 9 per cent of its share value wiped out yesterday after a misinterpreted comment about one of its late-stage development drugs.
In a conference call to discuss the company's 2011 results, chief executive Jean-Paul Clozel alluded to deaths in the phase III SERAPHIN trial of macitentan - a successor to its top-selling Tracleer (bosentan) for pulmonary arterial hypertension (PAH).
This resulted in a newswire article which implied that there may be a problem with the programme, which is not due to generate results for several weeks.
SERAPHIN is looking at macitentan's ability to improve both morbidity and mortality in PAH patients, so deaths are expected and in fact are a signal to start concluding the trial in preparation for statistical analysis of the results.
Until the data is clarified the cause of the deaths will not be clear.
The reaction in Actelion's share price (which has started to recover ground today) reflects the importance attributed to macitentan in the face of pressure on Tracleer sales from rival PAH drug Letairis (ambrisentan) from Gilead Sciences.
Sales of Tracleer fell 7 per cent in 2011 to 1.52bn Swiss francs ($1.66bn), with Actelion's total revenues slipping by the same margin to 1.8bn francs.
Meanwhile, Letairis grew 22 per cent to $293m in the same period thanks to the approval of new labelling in the US which removed a warning about liver toxicity.
Action's revenues from Ventavis (iloprost), another PAH drug, also slipped 10 per cent to 106m francs, while turnover of Gaucher disease therapy Zavesca (miglustat) was flat at 69m francs.
The Swiss firm posted a net loss of 146m francs in 2011, swinging from a profit of 390m francs in 2010, and is expecting single-digit declines in product sales in 2012.
Clozel said that the company is now looking to its product pipeline - including macitentan - to restore the growth trajectory it has enjoyed in the last decade.
In addition to the phase III trial in PAH, Actelion has also started a pivotal study of macitentan in patients with ischemic digital ulcers associated with systemic sclerosis.
Other pipeline prospects include selexipag, another PAH candidate in phase III testing, oral multiple sclerosis therapy ponesimid in phase IIb, and asthma and allergic rhinitis drug setipripant in phase II.