Keryx Biopharmaceuticals (KERX) shares have tumbled in trading today after the company announced that an interruption in the supply of Auryxia (ferric citrate) tablets is imminent due to a production-related issue converting active pharmaceutical ingredient to finished drug product. The company expects to make Auryxia available to patients when supply of Auryxia is back to adequate levels. The company expects to restore adequate supply of Auryxia and to make Auryxia available to patients during the fourth quarter of 2016. KERX though has withdrawn its 2016 financial guidance due to the development. KERX also reported its second-quarter financial results, posting a loss of $0.42 per share. The company's revenue for the quarter was $9.29 million, up 270.1% on a year-over-year basis. Revenue beat consensus forecast by $0.72 million.