NuPathe has one product that might bring quick cash - Zecuity, a migraine medicine delivered through a patch.
NuPathe said in several 2012 filings with the Securities and Exchange Commission and in conference calls with financial analysts that it was seeking a buyer, while cutting costs and delaying the launch of Zecuity long enough to keep functioning.
On Dec. 23, Endo offered $105 million, with provisions for paying more if the drug met regulatory and sales milestones.
On Monday, Teva offered at least $149 million, with similar provisions for future payments, according to NuPathe's Wednesday filing with the SEC. Teva confirmed the offer. On the news, NuPathe shares soared 35.6 percent, or $1.15, to close at $4.38.
Endo's first payment was based on a stock price of $2.85 per share. Teva's first payment is based on a stock price of $3.65 per share. Teva also said it would make "additional payments of up to $3.15 per share" if Zecuity met sales goals.
NuPathe CEO Armando Anido and the NuPathe board had approved the Endo offer before the December announcement and said in a statement that it was good for stockholders. While he didn't retreat from that in Wednesday's SEC filing, he did say the offer from Teva was good enough that the NuPathe board had a fiduciary responsibility to consider it.
Anido also said that Teva, like Endo, is prepared to loan NuPathe money to cover "ongoing operations," pending the close of a merger agreement and that Teva would pay the termination fee involved in the Endo agreement.
An Endo spokesman declined to comment.
Meanwhile, Reuters reported that South Korean media s said Teva, Roche, and AstraZeneca were among the companies bidding for Celltrion Inc., a large drugmaker in that nation. Celltrion said last week that its largest shareholder was in talks with interested parties to sell a controlling stake in the company. Reuters said a Celltrion spokesman declined to comment.