August 29, 2011

Dear Icagen Stockholder:

As you are aware, Pfizer, Inc. is offering to pay you $6 net per share in cash for each share of Icagen common stock that you own. In order to satisfy the minimum condition of Pfizer's offer, which must be achieved for you to receive your cash payment from the tender offer, it is essential that you tender your shares regardless of the number of shares you own.   The tender offer is scheduled to expire at 12:00 midnight at the end of August 31, 2011, New York City time, unless extended.

On Friday, August 26, 2011, Pfizer delivered a letter to your Board of Directors restating that $6.00 was their best and final price.The tender offer is conditioned upon, among other things, at least a majority of Icagen's outstanding shares on a fully-diluted basis being tendered. The letter we received from Pfizer stated that the $6.00 offer price would not be raised, even if we fail to reach this condition. 

 IF THE MINIMUM CONDITION OF AT LEAST A MAJORITY OF ICAGEN'S OUTSTANDING SHARES ON A FULLY DILUTED BASIS IS NOT REACHED, THERE IS NO ASSURANCE THAT PFIZER WILL EVER ENGAGE IN A FUTURE TRANSACTION TO ACQUIRE YOUR SHARES.

Your Board of Directors unanimously recommends that stockholders accept the Pfizer offer and tender their shares in the offer. The $6 offer represents a premium of 150% to the $2.40 closing price of Icagen stock on June 24^th, the day before we announced we had entered into negotiations regarding a possible strategic transaction.

If you have any questions regarding the Pfizer offer or need help in tendering your shares, please call either Morrow & Co., LLC at (800) 276-3011, or MacKenzie Partners, Inc. at (800) 322-2885.

On behalf of the directors and management of Icagen, thank you for the support you have given Icagen over the years.

Sincerely,

P. Kay Wagoner, Ph.D.

President and Chief Executive Officer

*** If you have already tendered your Icagen shares, thank you for your support.***

About Icagen

Icagen, Inc. is a biopharmaceutical company based in Research Triangle Park, North Carolina, focused on the discovery, development and commercialization of novel orally-administered small molecule drugs that modulate ion channel targets. Utilizing its proprietary know-how and integrated scientific and drug development capabilities, Icagen has identified multiple drug candidates that modulate ion channels. The Company is conducting research and development activities in a number of disease areas, including epilepsy, pain and inflammation. The Company has two clinical stage programs in epilepsy and pain. To learn more about Icagen, please visit our website at www.icagen.com.

The Icagen, Inc. logo is available at http://www.globenewswire.com/newsroom/prs/?pkgid=5735

Important Information about the Tender Offer

The description contained in this press release is neither an offer to purchase nor a solicitation of an offer to sell securities. Any offers to purchase or solicitation of offers to sell will be made only pursuant to a tender offer statement and a solicitation and recommendation statement filed with the Securities and Exchange Commission ("SEC"). The tender offer statement (including an offer to purchase, a related letter of transmittal and other tender offer documents) and the solicitation/recommendation statement contain important information that should be read carefully before making any decision to tender securities in the tender offer. Those materials have been made available to the Company's stockholders at no expense to them. In addition, all of those materials (and all other tender offer documents filed with the SEC) are made available at no charge on the SEC's website at www.sec.gov.

source:Icagen