2023 Neurocrine Collaboration
On January 8, 2023, we entered into a second collaboration agreement, or the 2023 Neurocrine Collaboration Agreement, with Neurocrine for the research, development, manufacture and commercialization of gene therapy products directed to the gene that encodes glucosylceramidase beta 1, or GBA1, for the treatment of Parkinson’s disease and other diseases associated with GBA1, or the GBA1 Program, and three new programs focused on the research, development, manufacture and commercialization of gene therapies designed to address central nervous system diseases or conditions associated with rare genetic targets, or the 2023 Discovery Programs, and, collectively with the GBA1 Program, the 2023 Neurocrine Programs.
Under the terms of the 2023 Neurocrine Collaboration Agreement, in February 2023 Neurocrine paid us an upfront payment of approximately $136.0 million and approximately $39.0 million for the purchase of 4,395,588 shares of common stock at a price of $8.88 per share. The 2023 Collaboration Agreement also provides for aggregate development milestone payments from Neurocrine for gene therapy products arising under the 2023 Neurocrine Programs, or the 2023 Collaboration Products, under (a) the GBA1 Program of up to $985.0 million and (b) each of the three 2023 Discovery Programs of up to $175.0 million for each 2023 Discovery Program. We may be entitled to receive aggregate commercial milestone payments for up to two 2023 Collaboration Products under the GBA1 Program of up to $950.0 million per 2023 Collaboration Product and for one 2023 Collaboration Product under each 2023 Discovery Program of up to $275.0 million per 2023 Discovery Program.
The 2023 Neurocrine Collaboration Agreement became effective on February 21, 2023. On February 23, 2023, we received the upfront payment, and the shares of our commons stock were issued and sold to Neurocrine pursuant to the applicable stock purchase agreement.
License Agreements
In October 2021, we entered into an option and license agreement with Pfizer, or the Pfizer Agreement, pursuant to which we granted Pfizer options to receive an exclusive license, or the Pfizer License Options, to certain TRACER Capsids to develop and commercialize certain AAV gene therapy candidates comprised of a capsid and specified Pfizer transgenes, or Pfizer Transgenes. Effective as of September 30, 2022, Pfizer exercised a Pfizer License Option with respect to a capsid for the specified Pfizer Transgene for potential treatment of a rare neurological disease. In connection with the exercise of the Pfizer License Option for a rare neurological disease, we granted Pfizer an exclusive, worldwide license, with the right to sublicense, under certain of our intellectual property, the rights to develop and commercialize rare neurological disease products utilizing the capsid candidate and incorporating the corresponding Pfizer Transgene, or the Pfizer Licensed CNS Products. Pfizer did not exercise its option to license a capsid for the potential treatment of a cardiovascular disease. As result, Pfizer’s right to exercise a Pfizer License Option for a cardiovascular disease has terminated in accordance with the terms of the Pfizer Agreement and all rights to capsids for that cardiovascular disease have reverted to us.
On July 28, 2023, Alexion, AstraZeneca Rare Disease, or Alexion, entered into a definitive purchase and license agreement for preclinical gene therapy assets and enabling technologies from Pfizer. Effective upon the closing of the transaction on September 20, 2023, Alexion acquired all of Pfizer’s rights under the Pfizer Agreement and became the successor-in-interest to Pfizer thereunder. We refer to the Pfizer Agreement following the acquisition, as the Alexion Agreement. The acquisition does not impact the material terms of the option and license agreement.
Under the terms of the Alexion Agreement, Pfizer has paid us an upfront payment of $30 million and a payment of $10 million in connection with the exercise of the Pfizer License Option, which we also refer to as the Alexion License Option, for a rare neurological disease during the fourth quarter of 2022. We are also eligible to receive specified development, regulatory, and commercialization milestone payments of up to an aggregate of $115 million for the first Pfizer Licensed CNS Product, which we also refer to as an Alexion Licensed CNS Product, to achieve the applicable milestone. On an Alexion Licensed CNS Product-by-Alexion Licensed CNS Product basis, we are also eligible to receive (a) specified sales milestone payments of up to an aggregate of $175 million per Alexion Licensed CNS Product and (b) tiered, escalating royalties in the mid- to high-single-digit percentages of annual net sales of each Alexion Licensed CNS Product. The royalties are subject to potential reductions in customary circumstances including patent claim expiration, payments for certain third-party licenses, and biosimilar market penetration, subject to specified