the countries of the world or (ii) seven years from the first commercial sale of each REGENX Rett and ALS licensed product. Upon expiration of the REGENX Rett and ALS License, the license granted to us becomes irrevocable, perpetual, royalty-free and fully paid-up. We have the right to terminate the REGENX Rett and ALS License upon a specified period of prior written notice. REGENX may terminate the REGENX Rett and ALS 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 REGENX Rett and ALS License, or, effective immediately, if we or our affiliates, or sublicensees commence any action against REGENX or its licensors to declare or render any claim of the licensed patent rights invalid or unenforceable. Either party may terminate the REGENX Rett and ALS License for material breach if such breach is not cured within a specified number of days. Upon termination of the REGENX Rett and ALS License, other than for REGENX’s material breach, we grant to REGENX 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 REGENX for the research, development and commercialization of products in any therapeutic indication.
Nationwide Children’s Hospital
In September 2016, we entered into exclusive license agreements with NCH, pursuant to which NCH granted us exclusive, worldwide licenses under certain patent rights to make, have made, use, sell, offer for sale and import any products covered by each license, or NCH licensed products, and a non-exclusive, worldwide license under certain technical information to develop and manufacture the NCH licensed products, in the field of therapies and treatments of Rett syndrome and ALS in human use, respectively. We refer to each of the Rett syndrome and ALS in human use licenses individually as a NCH License. The patent rights exclusively in-licensed from NCH and relevant to our contemplated Rett syndrome product are a currently pending patent application being pursued only in the United States. The patent application covers the use of the aaV9 vector delivered intrathecally for the treatment of Rett syndrome. If a patent issues from this patent application, it is expected to expire in 2029. The patent rights exclusively in-licensed from NCH and relevant to our contemplated ALS product are a currently pending patent application being pursued in the United States, Canada and Europe. The patent application claims the use of the AAV9 vector as a composition of matter and its use for the treatment of ALS. If a patent issues from this patent application, it is expected to expire in 2035. We have the right to subcontract the manufacturing of products using the licensed rights under each NCH License. We also have the right to sublicense the licensed technology under each NCH License to third parties through multiple tiers.
Each NCH License sets forth a development plan for our development of the licensed technology to make and sell NCH licensed products, including for the treatment of Rett syndrome and ALS in humans, as applicable, throughout the world. We are required, if commercially reasonable, to market NCH licensed products after regulatory approval, satisfy the market demand for such products in those countries in which we have obtained regulatory approval and where it is commercially reasonable to do so and continue to develop additional NCH licensed products within the applicable field. In the event we fail to comply with such obligations, subject to certain conditions, NCH has the right to either terminate the applicable NCH License or convert our license into a non-exclusive license with respect to the applicable NCH licensed product in the applicable country. We are responsible for all clinical trial costs under each NCH License.
We paid an initial fee of $0.2 million to NCH in connection with the NCH License for Rett syndrome and $0.1 million in connection with the NCH License for ALS in human use. We also must pay NCH an annual maintenance fee under each NCH License. Following the first commercial sale of an NCH licensed product under an applicable NCH License, we must begin paying NCH an aggregate low-single digit royalty on net sales of NCH licensed products by us, our affiliates and sublicensees during the term of such license. If we unsuccessfully challenge any of the licensed patents, the royalty rate increases from low single digits to mid-single digits, in the case of the NCH License for Rett syndrome, and to high-single digits, in the case of the NCH License for ALS in human use.
With certain exceptions, we are required to make certain development milestone-based payments to NCH under each NCH License. In addition, we must also pay NCH a portion of sublicensing revenue received from our sublicense of the rights to licensed technology at a mid-single digits percentage.
We do not have the right to control prosecution of the in-licensed patent rights under either NCH License, however NCH shall consult with us on material matters regarding the prosecution of such patent rights, and NCH has the first right to enforce any patents issuing from the in-licensed patent rights and if NCH does not enforce the rights within a certain