The following table summarizes our recognized intangible assets as a result of the arrangements described in the following sections:


	June 30, 2022				December 31, 2021
	Weighted-average Estimated Useful Lives	Amount			Weighted-average Estimated Useful Lives	Amount
		(in thousands)				(in thousands)
Gross amount	12.5 years	$	32,500		12.8 years	$	47,500
Less accumulated amortization			(2,592	)			(2,566	)
Net book value		$	29,908			$	44,934

Amortization expense recorded as part of cost of license revenue and products sold for the three and six months ended June 30, 2022 was $0.6 million and $1.2 million, respectively. Amortization expense during the comparative periods was not material. Future amortization expense is $1.2 million for the remainder of 2022, $2.4 million for each of the years from 2023 to 2026 and $19.1 million thereafter.

In January 2018, QED entered into a License Agreement with Novartis International Pharmaceutical, Inc. (“Novartis”), pursuant to which QED acquired certain intellectual property rights, including patents and know-how, related to infigratinib for the treatment of patients with FGFR-driven diseases. If certain substantial milestones are met, QED could be required to pay up to $60.0 million in regulatory milestone payments, $35.0 million in sales-based milestone payments, and pay royalties of up to low double-digit percentages on net sales. Following the approval by the U.S. Food and Drug Administration (“FDA”) of TRUSELTIQTM in May 2021, we paid a one-time regulatory milestone payment to Novartis of $20.0 million. We capitalized such payment as a finite-lived intangible asset and amortize the amount over its estimated useful life on a straight-line basis.

In June 2018, our subsidiary Origin Biosciences, Inc. (“Origin”) entered into an Asset Purchase Agreement (the “Origin-Alexion APA”) with Alexion Pharma Holding Unlimited Company (“Alexion”) to acquire intellectual property rights, including patent rights, know-how, and contracts, related to the ALXN1101 molecule. Pursuant to the Origin-Alexion APA, Origin could be required to pay up to $18.8 million if a certain condition is met. Such a condition was met in 2021, resulting in a one-time final payment of $15.0 million, which we capitalized as a finite-lived intangible asset and amortize it over its estimated useful life on a straight-line basis. In addition, under the Origin-Alexion APA, Origin could also be required to pay up to $1.0 million in regulatory-based milestone payment, $17.0 million in sales-based milestone payments and royalties of up to low double-digit percentages on net sales.

In connection with the Asset Purchase Agreement entered into between Origin and Sentynl Therapeutics, Inc. (“Sentynl”) in March 2022 (the “Origin-Sentynl APA”, see Note 12), Sentynl assumed the obligation to pay sales-based milestone payments and royalties to Alexion that occur subsequent to the closing of the Origin-Sentynl APA when they become due. Origin will continue to be responsible for a regulatory-based milestone payment of up to $1.0 million when it becomes due. As a result of the Origin-Sentynl APA, we also derecognized the associated intangible asset with a net book value of $13.5 million as this was part of the assets that were transferred to Sentynl.

In November 2018, QED and Foundation Medicine, Inc. (“FMI”) entered into a companion diagnostics agreement relating to QED’s drug discovery and development initiatives. Pursuant to the agreement, QED could be required to pay $12.5 million in regulatory approval milestones over a period of four years subsequent to the FDA approval of a companion diagnostic for TRUSELTIQ in patients with cholangiocarcinoma. The FDA approved the companion diagnostic for TRUSELTIQ in May 2021, which resulted in the capitalization of $12.5 million as a finite-lived intangible asset to be amortized over its estimated useful life on a straight-line basis. We paid the first installment due to FMI of $1.5 million during the second quarter of fiscal year 2022 and as of June 30, 2022, the remaining amount due is presented in our condensed consolidated balance sheet in “Other accrued liabilities” for $2.5 million and “Other long-term liabilities” for $8.5 million. As of December 31, 2021, the amount due to FMI is presented in our condensed consolidated balance sheet in “Other accrued liabilities” for $1.5 million and “Other long-term liabilities” for $11.0 million. Refer to Note 11 for related discussion on the amount due to FMI.