United Therapeutics Corp. took a hit Oct. 23 as FDA issued a “complete response” letter for its December 2011 NDA seeking approval for oral tresprostinil as monotherapy in pulmonary arterial hypertension (PAH) patients. Some Wall Street investment houses downgraded the Maryland specialty pharma’s stock, which tumbled 15.5% in trading Oct. 24, finishing the day down $8.30 to $45.00 per share.
Treprostinil already is the backbone of United’s business, which has posted solid annual sales growth in recent years. In injectable...