, general counselmark r. sullivan, general counseloffice : 215 # # # - # # # - # # # # mobile : 856 # # # - # # # - # # # # * * * @ * * * exhibit 10. 58july 24, 2020via email : * * * @ * * * & * * * @ * * * jim neal, ceobob maddox, corporate counselxoma corporation2200 powell street, suite 310emeryville, ca 94608re : non - exclusive license agreement, dated as of november 30, 2001 ( the “ agreement ” ), by and between xoma ( us ) llc as assignee from xoma ireland limited ( the “ licensor ” ) and viventia bio inc. as assignee from viventia biotech inc. ( the “ company ” ) dear jim and bob : as you are aware, viventia bio inc. is a wholly - owned subsidiary of sesen bio, inc. under the terms of the agreement the licensor licensed to the company certain intellectual property rights and the company is utilizing those rights in connection with the development and commercialization of licensed products such as vb4 - 845, also known as vicineum, a locally - administered targeted fusion protein. as you may also be aware, the company is in the process of seeking partners for the development and commercialization of this licensed product outside the united states. in connection therewith, the company proposes to memorialize certain understandings and modifications to the agreement as set forth in this letter agreement ( the “ letter agreement ” ) to assist the company in its partnering efforts, which will benefit both the licensor and the company. 1. section 2. 1 of the agreement shall be deleted in its entirety and replaced with the following : “ 2. 1grant. subject to the terms and conditions of this agreement, xoma hereby grants to viventia and its affiliates a non - exclusive, non - transferable ( except as permitted under section 10. 2 ), worldwide license under the licensed technology to make, have made, use, import, offer for sale and sell licensed products in the field and the limited right to grant third party sublicenses to make, have made, use, import, offer for sale and sell licensed products developed pursuant to the agreement. any such third party sublicense will be consistent with the terms and conditions of this agreement,