Under the Progenics Purchase Agreement, the Company acquired rights to the HIV viral-entry inhibitor drug candidate PRO 140, a humanized anti-CCR5 monoclonal antibody, as well as certain other related assets, including the existing inventory of bulk PRO 140 drug product, intellectual property, certain related licenses and sublicenses, and FDA regulatory filings. In connection with purchase, the Company has one remaining milestone payment of $5.0 million, which will become due at the time of the first U.S. new drug application approval by the FDA or other approval for the sale of PRO 140. In addition, the Company will incur royalty payments of up to 5% on net sales during the period beginning on the date of the first commercial sale of PRO 140 until the later of (a) the expiration of the last to expire patent included in the acquired assets, and (b) 10 years, in each case determined on a country basis. During the year ended May 31, 2016 the Company paid a milestone obligation of $1.5 million owed to Progenics as a result of the first dosing in a U.S. Phase 3 trial. To the extent that the remaining milestone payment and royalties are not timely made, under the terms of the Progenics Purchase Agreement, Progenics has certain repurchase rights relating to the assets sold to the Company thereunder. As of the date of this filing, it is management’s conclusion that the probability of achieving the subsequent future scientific research milestone is not reasonably determinable, thus the future milestone payments payable to Progenics and its are deemed contingent consideration and, therefore, are not currently accruable. Payments to the third-party licensor and to Progenics are in addition to payments due under a Development and License Agreement, dated April 30, 1999 (the “PDL License”), between Protein Design Labs (now AbbVie Inc.) (“PDL”) and Progenics, which was assigned to the Company in the Progenics Purchase Agreement, pursuant to which the Company has an exclusive worldwide license to develop, make, have made, import, use, sell, offer to sell or have sold products that incorporate the humanized form of the PRO 140 antibody developed by PDL under the agreement the Company has paid various milestone obligations, with two remaining milestone payments of $0.5 million each, one payment of $0.5 million upon filing a BLA with the FDA or equivalent regulatory body and a second payment of $0.5 million, which will become due upon FDA approval or approval by anothernon-U.S. equivalent regulatory body. In addition, the Company will incur royalties of up to 3.5% of net sales for the longer of 10 years and the date of expiration of the last to expire licensed patent. Additionally, the PDL License provides for an annual maintenance fee of $150,000 or until annual royalties paid exceed that amount. To the extent the remaining milestone payment and royalties are not timely made, under the terms of the PDL License, AbbVie Inc. has certain termination rights relating to the Company’s license of PRO 140 thereunder. As of the date of this filing, it is management’s conclusion that the probability of achieving the subsequent future scientific research milestones is not reasonably determinable, thus the future milestone payments payable to PDL, Progenics and its

During the fourth quarter of fiscal 2019, the Company entered into a Master Services Agreement and Product Specific Agreement (collectively, the “Samsung Agreement”) with Samsung BioLogics Co., Ltd. (“Samsung”), pursuant to which Samsung will perform technology transfer, process validation, manufacturing and supply services for the commercial supply of leronlimab. In April 2019 the Company delivered to Samsung a purchase order for $33 million worth of process validation and technology transfer services related to the manufacture of leronlimab, with payments by the Company scheduled to be made throughout calendar 2020. Under the Samsung Agreement, the purchase order is binding and the Company is obligated to pay the full amount of the purchase order. Under the terms of the Samsung Agreement, the Company is obligated to make specified minimum purchases of leronlimab from Samsung pursuant to forecasted requirements which the Company will provide to Samsung. The first forecast will be delivered to Samsung by March 31, 2020. Thereafter, the Company must provide Samsung with a rolling quarterly forecast setting forth the total quantity of commercial grade leronlimab that the Company expects to require in the following years. The Company estimates that initial ramp-up costs to manufacture commercial grade leronlimab at scale could total approximately $60 million, with approximately $30 million payable over the course of calendar 2020, and approximately $30 million payable in the first quarter of 2021. Thereafter, the Company will pay Samsung per 15,000L batch according to the pricing terms specified in the Samsung Agreement. The Samsung Agreement has an initial term ending in December 2027 and will be automatically extended for additional two year periods unless either party gives notice of termination at least six months prior to the then current term. Either party may terminate the Samsung Agreement in the event of the other party’s insolvency or uncured material breach, and the Company may terminate the agreement in the event of a voluntary or involuntary complete market withdrawal of leronlimab from commercial markets, with one and half year’s prior notice. Neither party may assign the agreement without the consent of the other, except in the event of a sale of all or substantially all of the assets of a party to which the agreement relates