Subsequent event	12 Months Ended
Dec. 31, 2022
Subsequent event
Subsequent event	15. Subsequent events 2023 Neurocrine Collaboration On January 8, 2023, the Company entered into 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 (“GBA1”) for the treatment of Parkinson’s disease and other diseases associated with GBA1 (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 (the “2023 Discovery Programs” and, collectively with the GBA1 Program, the "2023 Neurocrine Programs”). Under the terms of the 2023 Neurocrine Collaboration Agreement, Neurocrine paid to the Company an upfront payment of approximately $136.0 million (the “Upfront Collaboration Payment”) and approximately $39.0 million as consideration (the “Share Consideration”) for an equity purchase of 4,395,588 shares of the Company’s common stock (the “Shares”) in February 2023. The 2023 Collaboration Agreement also provides for aggregate development milestone payments from Neurocrine for gene therapy products arising under the 2023 Neurocrine Programs (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. The Company 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, upon expiration of the applicable waiting period under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended. On February 23, 2023, the Company received the Upfront Collaboration Agreement and the Share Consideration and issued and sold to Neurocrine the Shares pursuant to the applicable stock purchase agreement. In connection with the execution of the 2023 Neurocrine Collaboration Agreement, the Company amended and restated their existing investor agreement on January 8, 2023 (the “2023 Neurocrine Amended and Restated Investor Agreement”), providing for standstill and lock-up restrictions and a voting agreement with respect to shares of the Company owned by Neurocrine. Novartis Option Exercises Effective as of March 1, 2023, Novartis exercised its Novartis License Options to license novel capsids generated from the Company’s TRACER capsid discovery platform for use in gene therapy programs against two undisclosed Initial Novartis Targets. With Novartis’ option exercise on two Initial Novartis Targets, the Company will receive a $25.0 million option exercise payment during the first half of 2023, and is eligible to receive associated potential development, regulatory, and commercial milestone payments, as well as mid- to high-single-digit tiered royalties based on net sales of the Novartis Licensed Products incorporating the Novartis Licensed Capsids. The two Initial Novartis Targets licensed are distinct from targets in the Company’s internal and partnered pipeline. In addition, over the next 18 months, Novartis retains the right to expand the agreement to include options to license capsids for up to two Additional Novartis Targets, subject to their availability, for a fee of $18.0 million per Additional Novartis Target. Under such an expansion, the Company would be eligible to receive a $12.5 million license option exercise fee for each Additional Novartis Target exercised, as well as future potential milestone payments per Additional Novartis Target and tiered mid- to high-single digit royalties on the Novartis Licensed Products incorporating the Novartis Licensed Capsids. Novartis elected not to license a capsid for one Initial Novartis Target under the Novartis Agreement prior to the expiration of the applicable Novartis License Option. As a result, the non-exclusive research license that we granted to Novartis in connection with this Initial Novartis Target has terminated, the Novartis Research Term for this Initial Novartis Target has expired, and we are no longer eligible to receive development, regulatory, and commercial milestone payments or royalties in connection with this Initial Novartis Target. All capsid rights with respect to that Initial Novartis Target have returned to the Company.

Subsequent event

12 Months Ended

Dec. 31, 2022

15. Subsequent events

2023 Neurocrine Collaboration

On January 8, 2023, the Company entered into 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 (“GBA1”) for the treatment of Parkinson’s disease and other diseases associated with GBA1 (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 (the “2023 Discovery Programs” and, collectively with the GBA1 Program, the "2023 Neurocrine Programs”).

Under the terms of the 2023 Neurocrine Collaboration Agreement, Neurocrine paid to the Company an upfront payment of approximately $136.0 million (the “Upfront Collaboration Payment”) and approximately $39.0 million as consideration (the “Share Consideration”) for an equity purchase of 4,395,588 shares of the Company’s common stock (the “Shares”) in February 2023. The 2023 Collaboration Agreement also provides for aggregate development milestone payments from Neurocrine for gene therapy products arising under the 2023 Neurocrine Programs (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. The Company 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, upon expiration of the applicable waiting period under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended. On February 23, 2023, the Company received the Upfront Collaboration Agreement and the Share Consideration and issued and sold to Neurocrine the Shares pursuant to the applicable stock purchase agreement.

In connection with the execution of the 2023 Neurocrine Collaboration Agreement, the Company amended and restated their existing investor agreement on January 8, 2023 (the “2023 Neurocrine Amended and Restated Investor Agreement”), providing for standstill and lock-up restrictions and a voting agreement with respect to shares of the Company owned by Neurocrine.

Novartis Option Exercises

Effective as of March 1, 2023, Novartis exercised its Novartis License Options to license novel capsids generated from the Company’s TRACER capsid discovery platform for use in gene therapy programs against two undisclosed Initial Novartis Targets. With Novartis’ option exercise on two Initial Novartis Targets, the Company will receive a $25.0 million option exercise payment during the first half of 2023, and is eligible to receive associated potential development, regulatory, and commercial milestone payments, as well as mid- to high-single-digit tiered royalties based on net sales of the Novartis Licensed Products incorporating the Novartis Licensed Capsids. The two Initial Novartis Targets licensed are distinct from targets in the Company’s internal and partnered pipeline. In addition, over the next 18 months, Novartis retains the right to expand the agreement to include options to license capsids for up to two Additional Novartis Targets, subject to their availability, for a fee of $18.0 million per Additional Novartis Target. Under such an expansion, the Company would be eligible to receive a $12.5 million license option exercise fee for each Additional Novartis Target exercised, as well as future potential milestone payments per Additional Novartis Target and tiered mid- to high-single digit royalties on the Novartis Licensed Products incorporating the Novartis Licensed Capsids.

Novartis elected not to license a capsid for one Initial Novartis Target under the Novartis Agreement prior to the expiration of the applicable Novartis License Option. As a result, the non-exclusive research license that we granted to Novartis in connection with this Initial Novartis Target has terminated, the Novartis Research Term for this Initial Novartis Target has expired, and we are no longer eligible to receive development, regulatory, and commercial milestone payments or royalties in connection with this Initial Novartis Target. All capsid rights with respect to that Initial Novartis Target have returned to the Company.