PTC Therapeutics details terms of Sangamo gene therapy asset deal

PTC Therapeutics and Sangamo Therapeutics signed an asset purchase agreement on August 25, 2026, under which PTC will acquire Sangamo's rights to ST-920, a one-time administered AAV gene therapy product candidate for Fabry disease, and assume certain specified liabilities of Sangamo.¹ Under the terms disclosed, PTC will pay $111 million upfront, with up to $100 million more available through contingent milestone payments.¹

Of that milestone total, $80 million would be paid if the FDA grants accelerated approval of a biologics license application for ST-920 for Fabry disease, based on results from Sangamo's Phase 1/2 "STAAR" study and its related long-term follow-up trial, while $20 million would follow full FDA approval based on the same studies, whether that comes as part of the original submission or through later conversion of an accelerated approval.¹

The transaction arises from Sangamo's Chapter 11 case. PTC had previously said it was selected as the winning bidder for ST-920 in a competitive bankruptcy auction tied to Sangamo's Chapter 11 proceeding.¹

Closing is contingent on several conditions. These include approval from the U.S. Bankruptcy Court for the District of Delaware, expiration or termination of the waiting period under the Hart-Scott-Rodino Act, and each party's accuracy on representations and performance of its obligations.¹ A bankruptcy court hearing on the deal is scheduled for September 10, 2026.¹

The agreement includes standard termination rights. These cover situations such as missed bankruptcy process deadlines or unfavorable court rulings, and either company can walk away if closing has not happened by October 15, 2026, subject to specified exceptions.¹

PTC agreed to use commercially reasonable efforts to reach the contingent milestone events.¹ The full agreement will be filed as an exhibit to PTC's quarterly report for the period ending September 30, 2026.¹