NEWTON, Mass. ( TheStreet) -- Clinical Data ( CLDA) scored a big victory with the approval of a new antidepressant, sending the stock price soaring 68% to $25.17 on Monday. Many of the company's shareholders and supporters, however, are looking for an even bigger payday when Clinical Data sells itself to the highest bidder. A sale of Clinical Data is seen as an obvious and inevitable next step, many current shareholders believe, because the company's new antidepressant Viibryd is a $2-3 billion-a-year blockbuster that will prove irresistible to any of the large pharmaceutical firms desperate for new growth. Clinical Data bulls are doubly confident in a sale because they have Randall J. Kirk on their side of the negotiating table. Kirk, Clinical Data's chairman and largest shareholder with a 37% stake, is known as a consummate dealmaker. He became a billionaire after selling New River Pharmaceuticals to Shire ( SHPGY) for $2.6 billion in 2007, but previous to that, he had a hand in Johnson & Johnson's ( JNJ) $2.3 billion purchase of Scios in 2003. At Monday's close and using a fully diluted share count, Clinical Data is worth over $1 billion already even with Viibryd still three or four months away from a commercial launch. Yet, bulls like Wedbush Securities analyst Greg Wade believe the company could be bought for upwards of $2 billion, or $40-plus per share. An institutional investor in Clinical Data who asked to remain anonymous believes Clinical Data is worth more, perhaps as much as $60 a share. Nonsense, say Clinical Data bears, including short sellers who initiated positions Monday on the stock's run-up following Viibryd's approval. To the bear's eye, Viibryd is me-too antidepressant with tolerability issues of its own. Sure, the $12 billion U.S. antidepressant marketing is attractive but cheap generics are grabbing a larger share of the market and insurers will throw reimbursement roadblocks in Viibryd's way. Clinical Data will be lucky to do $300 million in peak Viibryd sales, the bears say. And while Kirk's money-making M&A track record is undeniable, bears say Shire was an obvious and desperate buyer for New River. With Viibryd, Kirk faces a tougher challenge and no obvious or desperate buyers. This makes Clinical Data look more like Savient Pharmaceuticals ( SVNT) or Vanda Pharmaceuticals ( VNDA) -- two small drug companies with stocks that spiked on drug approvals only to fall sharply in the following weeks and months. The former couldn't find a buyer and was forced to sell its gout drug solo; the latter found a partner, Novartis, to market its schizophrenia drug but so far, hardly anyone is prescribing it.