8. Gemma License Agreement

On July 31, 2024, the Company entered into a series of sublicense agreements with Gemma in connection with the outlicense of PBGM01 for the treatment of GM1 gangliosidosis, or GM1, PBKR03 for the treatment of Krabbe disease, or Krabbe, and PBML04 for the treatment of metachromatic leukodystrophy, or MLD, collectively the Outlicensed Programs, and such agreements, the Gemma Sublicenses. On May 7, 2025, the Company agreed to amend each of the Gemma Sublicenses to revise certain financial terms related to the Outlicensed Programs, or the Amended Gemma Sublicenses. Pursuant to the Amended Gemma Sublicenses, the Company is entitled to receive (i) an aggregate total of $15.0 million in initial payments for licenses and clinical product supply, of which $7.5 million was previously received, $2.5 million of which was due in May 2025, and $5.0 million of which is due in March 2026; (ii) an additional $5.0 million contingent on Gemma completing certain business milestones; (iii) up to an additional $114.0 million in development and commercial milestone payments; and (iv) single digit royalties as a percentage of annual worldwide net sales, in exchange for sublicenses to relevant intellectual property, transfer of regulatory dossiers and transfer of clinical trial materials and product supply related to the Outlicensed Programs. Gemma will be responsible for all payments due to the Trustees of the University of Pennsylvania’s, or Penn, under the Company’s research, collaboration and licensing agreement with Penn, or the Penn License Agreement, related to the Outlicensed Programs. On July 31, 2024, the Company also entered into a transition services agreement with Gemma, or the Transition Services Agreement, as amended by the First Amendment to the Transition Services Agreement, dated January 31, 2025, pursuant to which, the Company provided transitional services at cost to Gemma through May 31, 2025, and is entitled to reimbursement for transitional services performed retroactively from March 1, 2024, related to the transfer of the Outlicensed Programs. As of December 31, 2025, the Company has collected $7.5 million in initial payments, $4.8 million in transition services payments, and applied $1.5 million in amounts owed to Gemma for the Huntington’s disease program against amounts due to the Company for transition services under these agreements.

As Gemma has a limited history of operations, the Company will not recognize revenue under ASC 606 until the Company either (i) has received payment and there are no remaining obligations to transfer goods and services under the Amended Gemma Sublicenses and Transition Services Agreement (as payments received by Gemma are nonrefundable), or (ii) concludes that substantially all of the transaction price is collectible. As of December 31, 2025, the Company has received initial payments of $7.5 million associated with the aggregate $15.0 million of initial payments to be made under the Amended Gemma Sublicenses for licenses and clinical product supply and $4.8 million associated with the Transition Services Agreement and applied $1.5 million in amounts owed to Gemma for the Huntington’s disease program against amounts due to the Company for transition services under these agreements. The Company recorded these amounts ($13.8 million) as non-refundable sublicense and transition services payments on the balance sheet as of December 31, 2025, as the criteria set forth above have not yet been met.