Sepracor slumps as US FDA turns down antihistamine product Soltara

Sepracor, a specialist in the development of single-isomer drugs, sawits shares spiral downwards on March 7 after the US Food and Drug Administration determined that its antihistamine Soltara (tecastemizole) was not approvable on the grounds that the company had not conducted sufficient safety testing on the drug. The company's Nasdaq-listed shares fell a massive 59% to $19.64 on the day of the announcement.

Sepracor chief executive Timothy Barberich told a conference call that the FDA's decision came as a complete surprise. He added that the firm will now, alongside its efforts to advance the Soltara application, focus on driving the market share of its marketed asthma drug Xopenex (levalbuterol tartrate) and advancing its late-stage clinical candidates: the insomnia drug Estorra (esopiclone), a metered dose inhaler formulation of Xopenex, (R,R)-formoterol for asthma and sustained-release oxybutynin for overactive bladder. The latter three drugs are all due for filing in the USA at the end of this year or early next.

Sepracor said that the FDA had identified three sticking points in the dossier, two of which related to observations of side effects in animals that were not observed in humans, phospholipidosis and cardiomyopathy, while the third, and likely most important issue, concerned the need for additional assurance of the absence of any potential for QTc prolongation, a form of irregular heart beat.