Mystery investment fund eyes $640M bid for struggling obesity drug maker Vivus

Vivus ($VVUS) has been through a lot over the past year, including an all-out proxy war, a myriad of exec exits and, most recently, a generic threat from Actavis ($ACT) to its flailing obesity drug Qsymia. And now? It appears to have an interested buyer, according to a regulatory filing.

Aspen Investments declared a 9.65% stake in the Mountain View, CA-based drugmaker Wednesday--and announced its desire to buy up the rest for $640 million. It's planning to submit a conditional offer to Vivus' board by June 13, Aspen said in a Securities and Exchange Commission filing. And it plans to finance that offer with help from "top-tier" investment banks, the fund said.

As TheStreet's Adam Feuerstein points out, the offer is a little mysterious. Aspen is a limited liability corporation registered in Delaware just a couple weeks ago, and the address corresponds to a house on the state's coast. And as the filing says, a majority of its stake in the company--which it built up between May 16 and May 23--is in forward purchase contracts, rather than shares.

Vivus has plenty to worry about while it waits for the official bid. As Actavis told the company earlier this month, it's already asked the FDA to approve its knockoff version and plans to bring a generic of Vivus' struggling weight-loss pill to market. And without a marketing partner for that drug, its sales are still sagging, with competitor Belviq from Arena Pharmaceuticals ($ARNA) hot on its heels.

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