** United Therapeutics UTHR.O shares up 7.6% to $514.45 on Mon after announcing new $2 bln stock buyback
** Silver Spring, Maryland-based firm early Mon said board-authorized repurchase program includes initial $1.5 bln ASP (accelerated share repurchase) agreements with Citibank C.N
** Remaining amount of up to $500 mln will be available for additional buybacks at co's discretion
** Buyback announcement comes one week after co said its drug, ralinepag, to treat a rare lung condition cut the risk of the disease worsening in late-stage study
** UTHR markets other FDA-approved pulmonary arterial hypertension (PAH) treatments, including oral drug Orenitram, continuous infusion therapy, Remodulin and inhaler-based Tyvaso and Tyvaso DPI
** TD Cowen, which rates UTHR 'buy' with $575 PT, says in note it believes the timing of the ASR program signals management's confidence in executing across the commercial franchise
** UTHR has nearly $23 bln market cap, based on ~43.8 mln shares outstanding
** With move on the session, stock up 6% YTD vs ~4% drop in Nasdaq .IXIC. Shares are off ~4% from Feb 25 record intraday high of $537.19
** Avg rating of 15 brokerages is "buy"; median PT of $575 up from $525 a month ago, per LSEG data
(Lance Tupper is a Reuters market analyst. The views expressed are his own)
((lance.tupper@tr.com 1-646-279-6380))