The Company has a license agreement with a third-party licensor covering the licensor’s “system  technology with respect to the Company’s use of proprietary cell lines to manufacture new PRO 140 material. The Company accrues an annual license fee of £300,000 (approximately US$365,000 utilizing current exchange rates), which is payable annually in December. The December 2018 payment date was extended to April 15, 2019 and the December 2017 date payment was extended to March 15, 2018. Future annual license fees and royalty rate will vary depending on whether the Company manufactures PRO 140, utilizes the third-party licensor as a contract manufacturer, or utilizes an independent party as a contract manufacturer. The licensor does not charge an annual license fee when it serves as the manufacturer. In addition, the Company will incur royalties of up to 2% of net sales when the Company commences their first commercial sale, which will continue as long as the license agreement is maintained.