The up-front payment was just $5 million, but a potential $225 million option and licensing deal between Opexa Therapeutics Inc. and Merck Serono SA to develop and commercialize Tcelna (imilecleucel-T), a personalized T-cell immunotherapy in multiple sclerosis (MS), could offer a win-win for the small biotech and for the biopharmaceutical division of Merck KGaA, of Darmstadt, Germany – provided the product crosses the finish line.