7. Licenses Acquired

In accordance with ASC 730‑10‑25‑1, Research and Development, costs incurred in obtaining technology licenses are charged to research and development expense if the technology licensed has not reached technological feasibility and has no alternative future use. The licenses purchased by Fortress, Aevitas, Avenue, Cellvation, Checkpoint, Cyprium, Helocyte, Mustang and Tamid require substantial completion of research and development, and regulatory and marketing approval efforts in order to reach technological feasibility. As such, for the three and six months ended June 30, 2019 and 2018, the purchase price of licenses acquired was classified as research and development-licenses acquired in the Condensed Consolidated Statements of Operations as reflected in the table below:

Mustang

In May 2017, the Company entered into an exclusive license agreement with the City of Hope National Medical Center (“COH”) for the use of CS1-specific chimeric antigen receptor (“CAR”) engineered T cell (“CAR T”) technology. Pursuant to this agreement, the Company paid an upfront fee of $0.6 million and pays an annual maintenance fee of $50,000. Additional payments are due for the achievement of ten development milestones totaling $14.9 million and royalty payments in the mid-single digits are due on net sales of licensed products.

In May 2019 the Company expensed a non-refundable milestone payment of $0.2 million upon the first patient dosed in a Phase 1 clinical study of CS1.

In February 2019, Mustang announced that it partnered and entered into an exclusive worldwide license agreement with Nationwide Children’s Hospital (“Nationwide”) to develop the C134 oncolytic virus (MB‑108) for the treatment of glioblastoma multiforme (“GBM”). Mustang intends to combine MB‑108 with MB‑101 (IL13R2‑specific CART) to potentially enhance efficacy in treating GBM. Mustang paid $0.2 million in consideration for the license for exclusive, worldwide rights to develop and commercialize products that incorporate data, know-how and/or C134 virus that were developed at Nationwide. Additional payments are due to Nationwide upon achievement of development and commercialization milestones totaling $152.8 million. Royalty payments in the low-single digits are due on net sales of licensed products.

For the three and six months ended June 30, 2019 and 2018, Mustang recorded the following expense in research and development for licenses acquired: