prosecution of the in‑licensed patent applications, and our rights to enforce the in‑licensed patents are subject to certain limitations.
Under the amendment to the REGENXBIO SMA License, we are permitted to transfer the REGENXBIO SMA License without REGENXBIO’s consent in connection with a change of control of us, subject to the transferee or successor agreeing in writing to be bound by the terms of the REGENXBIO SMA License and the payment to REGENXBIO of the first and second anniversary fees of $30.0 million and $30.0 million, as well as the first $40.0 million in milestone fees, to the extent not already paid. Under the original REGENXBIO SMA License, any assignment by us without REGENXBIO’s prior written consent had been prohibited.
Our license agreement with REGENXBIO will expire upon the expiration, lapse, abandonment or invalidation of the last claim of the licensed intellectual property in all the countries of the world. We have the right to terminate the REGENXBIO SMA License upon a specified period of prior written notice. REGENXBIO may terminate the REGENXBIO SMA License if we or our affiliates become insolvent, if we are greater than a specified number of days late in paying money due under the REGENXBIO SMA License, or, effective immediately, if we or our affiliates, or sublicensees commence any action against REGENXBIO or its licensors to declare or render any claim of the licensed patent rights invalid or unenforceable. Either party may terminate the REGENXBIO SMA License for material breach if such breach is not cured within a specified number of days. Upon termination of the agreement, other than for REGENXBIO’s material breach, we grant to REGENXBIO a non‑exclusive, perpetual, irrevocable, worldwide, royalty‑free, transferable, sublicenseable license under patentable modifications and improvements to any vector claimed by the licensed patents for use by REGENXBIO for the research, development and commercialization of products in any therapeutic indication.
Asklepios Biopharmaceutical, Inc.
In May 2015, we entered into a non‑exclusive license agreement with Asklepios Biopharmaceutical, Inc., or the AskBio License. Pursuant to the license agreement, AskBio granted us a non‑exclusive, worldwide license under certain patent rights and know‑how owned or controlled by AskBio, including certain patent rights owned by the University of North Carolina and licensed to AskBio, and relating to its self‑complementary DNA technology to develop, make, have made, use, sell, offer to sell, import, export and distribute any products covered by the AskBio License, or AskBio licensed products, for the treatment of SMA in humans. The in‑licensed patent rights are issued patents in the United States, and in Canada and Europe. There are two in‑licensed patent families. The first patent family expires in November 2019 worldwide. The second patent family includes three issued United States patents with expiry dates between May 2021 and August 2023. The foreign counterparts expire in 2021. The patents relate to self‑complementary technology and include claims to viral particles based on such technology, methods of manufacturing such viral particles, and methods of use in treatment. We have the right to sublicense the licensed technology to third parties with AskBio’s prior approval. We assign to AskBio all right, title and interest in and to defined improvements to the licensed technology that we make and all patent rights covering those improvements. In return, we receive a non‑exclusive, worldwide, royalty‑free, transferable, sublicenseable, irrevocable, perpetual license to practice such improvements.
The AskBio License required us to pay AskBio a one‑time upfront license fee of $1.0 million and an ongoing annual maintenance fee of $0.1 million each year during the term of the license agreement. We are also required to pay up to a total of $0.6 million in clinical development milestone payments and $9.0 million in sales based milestone payments.
Under the terms of the AskBio License, we are required to pay AskBio annual tiered royalties based on the aggregate net sales of AskBio licensed products on a field‑by‑field basis starting at percentages in the low‑single digits and increasing to mid‑single digits. The royalties are payable on a country‑by‑country basis until the last to expire of the valid claims within the licensed patents that cover the AskBio licensed product in such country. These royalty rates are subject to reductions in specified circumstances, including, in the event we exercise our option to make a specified one‑time royalty option fee payment of $3.0 million to AskBio as further detailed in the AskBio License. We must also pay AskBio a low‑double digit percentage of all consideration we receive from our sublicense of the licensed technology.