Definite-lived intangibles

On April 20, 2017, the Company completed its previously announced acquisition of all rights to Emflaza pursuant to the Asset Purchase Agreement, dated March 15, 2017, and amended on April 20, 2017, by and between the Company and Marathon. The assets acquired by the Company in the Transaction include intellectual property rights related to Emflaza, inventories of Emflaza, and certain contractual rights related to Emflaza. In accordance with ASU No. 2017-01, the Company determined that substantially all of the fair value is concentrated in the Emflaza rights intangible asset and as such accounted for the transaction as an asset acquisition under ASC 805-50 and recorded an intangible asset of $148.4 million.

The Emflaza rights intangible asset is being amortized to cost of product sales over its expected useful life of approximately 7 years on a straight line basis.

Marathon is entitled to receive contingent payments from the Company based on annual net sales of Emflaza beginning in 2018, up to a specified aggregate maximum amount over the expected commercial life of the asset. In accordance with the guidance for an asset acquisition, the Company will record the milestone payment when it becomes payable to Marathon and increase the cost basis for the Emflaza rights intangible asset.

For the twelve month period ended December 31, 2018, the Company recorded $14.4 million of milestone payments due to net sales of Emflaza, which were added to the cost basis for the Emflaza rights intangible asset and will be amortized prospectively on a straight-line basis over the remaining life of the asset. As of December 31, 2018, a milestone payable to Marathon of $6.0 million was recorded on the balance sheet within accrued expenses.

For the twelve month periods ended December 31, 2018 and 2017, the Company recognized amortization expense of $22.9 million and $15.4 million, respectively, related to the Emflaza rights intangible asset, resulting in accumulated amortization of $38.3 million as of December 31, 2018.The estimated future amortization of the Emflaza rights intangible asset is expected to be as follows:



	As of December 31, 2018
2019	$	24,283
2020	24,276
2021	24,277
2022	24,277
2023 and thereafter	27,418
Total	$	124,531

Indefinite-lived intangibles

In connection with the acquisition of Agilis (Note 3), the Company acquired rights to PTC-AADC, for the treatment of AADC deficiency. AADC deficiency is a rare CNS disorder arising from reductions in the enzyme AADC that result from mutations in the dopa decarboxylase gene. The Agilis platform also includes a gene therapy asset targeting Friedreich ataxia, a rare and life-shortening neurodegenerative disease caused by a single defect in the FXN gene which causes reduced production of the frataxin

protein. An investigational new drug ("IND") submission with the FDA for this program is expected in late 2019. Additionally, the Agilis platform includes two other gene therapy programs targeting CNS disorders, including Angelman syndrome, a rare, genetic, neurological disorder characterized by severe developmental delays.

In accordance with the acquisition method of accounting, the Company allocated the acquisition cost for the Merger to the underlying assets acquired and liabilities assumed, based upon the estimated fair values of those assets and liabilities at the date of acquisition. The Company classified the fair value of the acquired IPR&D as indefinite lived intangible assets until the successful completion or abandonment of the associated research and development efforts. The value allocated to the indefinite lived intangible assets was $576.5 million.

Goodwill

As a result of the Merger on August 23, 2018, the Company recorded $82.3 million of goodwill, which included a measurement period adjustment of $18.0 million recorded during the three month period ended December 31, 2018. This adjustment was related to the finalization of the fair values assigned to the intangible assets and corresponding deferred tax liability, the contingent consideration, and the deferred consideration. Refer to Note 3 for further details.

Collaboration and Licensing Agreement

On August 1, 2018, the Company entered into a Collaboration and License Agreement with Akcea for the commercialization of Tegsedi and Waylivra, and products containing those compounds in countries in Latin America and the Caribbean. Pursuant to the agreement, the Company paid Akcea an upfront licensing fee, which included an initial payment of $12.0 million. An additional $6.0 million is payable within 30 days after receipt of regulatory approval of Waylivra from the United States Food and Drug Administration or the European Medicines Agency, whichever occurs earlier. The Company evaluated the agreement under the guidance in ASC 730 and concluded that the acquired rights to commercialize the products had no alternative future use as of the date of the Merger. Accordingly, the $12.0 million was charged to research and development expense in the consolidated statements of operations for the twelve month period ended December 31, 2018. The Company recently filed a request for marketing authorizations for Tegsedi with ANVISA. Waylivra is currently under regulatory review in the EU.