Merck has a one-time option to license certain NGM pipeline programs – not including aldafermin, NGM395 and NGM386 – following human proof-of-concept trials under the terms of the companies' ongoing strategic collaboration. Upon exercising any such option, Merck would lead global product development and commercialization for the resulting products, if approved. Prior to Merck initiating a Phase 3 study for a licensed program, NGM may elect to either receive milestone and royalty payments or to co-fund development and participate in a global cost and revenue share arrangement of up to 50%. The agreement also provides NGM with the option to participate in the co-promotion of any co-funded program in the United States. In November 2018, Merck exercised its first option under the collaboration to license MK-3655, previously referred to as NGM313.