Pfizer has completed its cash tender offer for the biopharmaceutical company Icagen (Durham, North Carolina) after extending its initial deadline twice. The tender offer of $6 per share was originally scheduled to expire on Aug. 31, 2011, but had to be extended on both Sept. 1 and Sept. 2 after insufficient shares were tendered.

When the first offer expired, Pfizer was just short of the shares required to finalize the deal when only 4,044,035 of the necessary 4,151,466 shares were tendered, despite Icagen reaffirming its recommendations for shareholders to accept the offer on two occasions. After an extension until the end of Thursday, Sept. 1, Pfizer was still 39,799 shares short, but a second extension until 6:00 pm on Friday, Sept. 2 proved more successful. Approximately 4,617,045 shares have now been tendered, giving Pfizer a 54% ownership of the company.

Pfizer and Icagen announced their intentions to merge in July 2011. According to a letter to Icagen shareholders, the $6 offer represented a premium of 150% to the $2.40 closing price of Icagen stock on June 24, 2011. The offer was unanimously recommended by Icagen’s board of directors and the aggregate transaction, including the shares already owned by Pfizer at the time, was valued at approximately $56 million.

According to a press release from investment firms Merlin Nexus and New Leaf Venture Partners, however, the offer undervalues the company. In particular, the investors are disappointed that the acquisition was announced ahead of near-term milestones involving pain programs partnered with Pfizer.

In a letter written to Icagen’s board of directors, the firms estimate the “value of Icagen's pain programs alone at as much as $100–$165 million or $11–$19 a share.” The release also adds: “Pfizer advanced the first of Icagen's proprietary compounds (PF-05089771) into a Phase I single-dose escalation study in December 2010, and this trial was expected to have been completed in March 2011. According to the letter, ‘trial data are open to Pfizer as they are required to monitor safety. These data provide Pfizer with an unfair advantage not afforded to all investors to determine the value of this program’.”