Opexa Therapeutics, Inc. (NASDAQ: OPXA) today announced the execution of an agreement with Merck Serono, a division of Merck, Darmstadt, Germany, for the development and commercialization of Tcelna ™ (imilecleucel-T), a potential first-in-class personalized T-cell therapy for patients suffering from multiple sclerosis (MS). Tcelna (imilecleucel-T) is being developed by Opexa and currently is in a Phase IIb clinical trial in patients with Secondary Progressive MS (SPMS). Potential payments to Opexa from the option and license agreement could total $225 million based upon the successful development and commercialization of Tcelna for MS. Tcelna (imilecleucel-T) is being developed as a personalized therapy specifically tailored to each patient’s individual disease profile and has been evaluated in Phase I and II clinical studies in MS that included SPMS patients. Tcelna (imilecleucel-T) has received Fast Track Designation from the United States Food and Drug Administration as a potential treatment for SPMS. Under the terms of the agreement, Opexa will receive an upfront payment of $5 million for granting an option to Merck Serono for the exclusive license of the Tcelna (imilecleucel-T) program for the treatment of MS. The option may be exercised prior to or upon completion of Opexa’s ongoing Phase IIb clinical trial in patients with SPMS. Upon exercising this licensing option, Merck Serono would pay an upfront license fee of either $25 million or $15 million (depending upon whether certain conditions are met), and in return receive worldwide development and commercial rights to Tcelna (imilecleucel-T) in MS, excluding Japan. After exercising the option Merck Serono would be wholly responsible for funding clinical development, subject to Opexa’s co-funding option, as well as regulatory and commercialization activities for the MS program. Additional financial considerations of the agreement include development and commercial milestone payments to Opexa of up to $195 million and a tiered royalty rate from the high single digits to the mid-teens based on net sales payable to Opexa. The potential payments to Opexa could, therefore, total $225 million excluding royalty payments.