Net revenue from our partners in connection with our collaboration and license agreements consisted of the following (in thousands):

	Three Months Ended March 31,
	2020		2019
Strategic Collaboration with Novartis	$	311	$	157,062
Vupanorsen (AKCEA-ANGPTL3-LRx) License Agreement with Pfizer		604		—
Total net revenue from partners	$	915	$	157,062

The following table presents the balance of our receivables and contract liabilities related to our collaboration and license agreements associated with our partners as of March 31, 2020 and December 31, 2019 (in thousands):

March 31,

2020

December 31,

2019

Receivables included in "Accounts receivable"

717

3,550

Contract liabilities included in "Deferred revenue"

718

1,322

During the three months ended March 31, 2020, we recognized the following revenue as a result of the change in the contract liability balances related to our collaboration and license agreements associated with our partners (in thousands):

Revenue recognized in current period from:

Three Months Ended

March 31, 2020

Amounts included in deferred revenue at the beginning of the period

604

In January 2017, we initiated a strategic collaboration with Novartis Pharma AG, or Novartis, for the development and commercialization of AKCEA-APO(a)-L_Rx and AKCEA-APOCIII-L_Rx. Under the terms of the Novartis collaboration, we agreed to complete a Phase 2 program, conduct an end-of-Phase 2 meeting with the U.S. Food and Drug Administration, or FDA, and provide initial quantities of the active pharmaceutical ingredient, or API, for each medicine. In March 2018, we extended our Phase 2 programs to include an expanded diverse population in which Novartis agreed to reimburse us for all costs. We recognized revenue of $0.3 million and $0.9 million for the three months ended March 31, 2020 and 2019, respectively, relating to the extended programs.

In February 2019, Novartis exercised its exclusive option to license AKCEA-APO(a)-L_Rx.Novartis is responsible for conducting and funding all future development, regulatory and commercialization activities for AKCEA-APO(a)-L_Rx. Novartis has full use of the license without any continuing involvement from us, therefore making the license distinct from other performance obligations. Accordingly, we recognized the related license fee of $150.0 million in full in February 2019 upon exercise. We issued 2,837,373 shares of our common stock to Ionis to satisfy the $75.0 million sublicense fee due to Ionis for Novartis’ option exercise under our development, commercialization and license agreement related to our cardiometabolic franchise, or Cardiometabolic License Agreement, with Ionis.

In the second quarter of 2019, we completed the development services performance obligation for AKCEA-APO(a)-L_Rx and all revenue allocated to this revenue stream was fully recognized as of June 30, 2019.

We are eligible to receive up to $675.0 million in additional milestone payments, including $25.0 million for the achievement of a development milestone, up to $290.0 million for the achievement of regulatory milestones and up to $360.0 million for the achievement of commercialization milestones. In connection with Novartis’ exercise of its option to exclusively license AKCEA-APO(a)-L_Rx, we and Novartis established a more definitive co-commercialization framework under which we and Novartis may negotiate the co-commercialization of AKCEA-APO(a)-L_Rx in select markets. Included in this framework is an option by which Novartis could solely commercialize AKCEA-APO(a)-L_Rx in exchange for Novartis paying us increased commercial milestone payments based on sales of AKCEA-APO(a)-L_Rx.

We will earn the next milestone payment of $25.0 million under this collaboration if Novartis reaches a specific level of enrollment related to the Phase 3 study for AKCEA-APO(a)-L_Rx. We are also eligible to receive tiered royalties in the mid-teens to low twenty percent range on net sales of AKCEA-APO(a)-L_Rx_. Novartis will reduce these royalties upon the expiration of certain patents or if a generic competitor negatively impacts the product in a specific country. We will share any milestone payments and royalties equally with Ionis. AKCEA-APO(a)-L_Rx was recently granted Fast Track Designation by the FDA as a potential treatment for people at significant risk for cardiovascular disease due to elevated levels of lipoprotein(a), or Lp(a).

In December 2019, we received written notice from Novartis electing not to exercise its option to license AKCEA-APOCIII-L_Rx and terminating the strategic collaboration solely in relation to AKCEA-APOCIII-L_Rx_.As such, the development services performance obligation relating to AKCEA-APOCIII-L_Rx no longer exists and all revenue allocated to the development services revenue stream was fully recognized as of December 31, 2019.

As a result of Novartis’ election not to exercise its option, we retain the rights to further develop and commercialize AKCEA-APOCIII-L_Rx. We are no longer entitled to any future license fees, milestone payments or royalties from Novartis relating to AKCEA-APOCIII-L_Rx.

We did not recognize any revenue relating to AKCEA-APO(a)-L_Rxor APOCIII-L_Rx during the three months ended March 31, 2020, compared to $156.2 million of revenue recognized during the three months ended March 31, 2019. As of March 31, 2020 and December 31, 2019, we did not have any remaining deferred revenue related to the strategic collaboration with Novartis on our condensed consolidated balance sheet.

In August 2018, we entered into a collaboration and license agreement with PTC Therapeutics, or the PTC License Agreement, to commercialize TEGSEDI and WAYLIVRA in Latin America and certain Caribbean countries, or the PTC Territory. In addition, in April 2019, we entered into a supply agreement with PTC Therapeutics providing them the option to purchase product from us subject to terms as described in the agreement. During the three months ended March 31, 2020, we recognized revenue of $0.4 million relating to the sale of TEGSEDI to PTC Therapeutics. This amount is included in net product revenue on our condensed consolidated statement of operations.

In May 2019, we received $6.0 million from PTC Therapeutics as a result of regulatory approval of WAYLIVRA in Europe. We paid Ionis a $3.0 million sublicense fee under our Cardiometabolic License Agreement and recorded it as a cost of license in our condensed consolidated statement of operations. In October 2019, we received $4.0 million from PTC Therapeutics as a result of regulatory approval of TEGSEDI in Brazil. We paid Ionis a $2.4 million sublicense fee under our development, commercialization, collaboration and license agreement with Ionis dated March 2018, or the TTR License Agreement, and recorded it as a cost of license in our condensed consolidated statement of operations. After receiving regulatory approval for WAYLIVRA and TEGSEDI, we deemed the milestone consideration probable, therefore we updated the transaction price to include these payments and accordingly, we recognized the $6.0 million and $4.0 million as license revenue during the second and fourth quarter of 2019, respectively. Prior to receiving regulatory approvals, we fully constrained these payments because regulatory approvals are not within our control.

We are eligible to receive an additional $4.0 million for the achievement of a regulatory milestone and royalties in the mid-twenty percent range on net sales of TEGSEDI and WAYLIVRA in the PTC Territory.

PTC Therapeutics’ obligation to pay royalties to us begins on the earlier of 12 months after the first commercial sale of a product in Brazil or the date that PTC Therapeutics recognizes revenue of at least $10.0 million in the PTC Territory. PTC Therapeutics will reduce these royalties upon the expiration of certain patents or if a generic competitor negatively impacts the market share of the product in the PTC Territory. Milestone payments and royalties that we are eligible to receive from PTC Therapeutics for TEGSEDI are split 60% to Ionis and 40% to Akcea in accordance with our TTR License Agreement. All WAYLIVRA milestone payments and royalties that we are eligible to receive from PTC Therapeutics are split equally with Ionis in accordance with our Cardiometabolic License Agreement. PTC Therapeutics is solely responsible for the commercialization of the products in the PTC Territory at its sole cost and expense, including the pursuit and maintenance of applicable regulatory approvals. Unless earlier terminated, the PTC License Agreement will continue in effect until the date on which the royalty term and all payment obligations with respect to all products in all countries in the PTC Territory have expired.

In October 2019, we entered into a license agreement with Pfizer, or the Pfizer Vupanorsen License Agreement, for the development and commercialization of vupanorsen (previously referred to as AKCEA-ANGPTL3-L_Rx). Under the terms of the Pfizer Vupanorsen License Agreement, we granted Pfizer an exclusive license to further develop, manufacture and commercialize vupanorsen worldwide, subject to our potential participation in co-commercialization. We are responsible for completing a Phase 2 study and providing quantities of API for vupanorsen.

We received a $250.0 million upfront payment in the fourth quarter of 2019 from Pfizer. We issued 6,873,344 shares of our common stock to Ionis as payment of the $125.0 million sublicense fee due under our Cardiometabolic License Agreement with Ionis.

At commencement of the Pfizer Vupanorsen License Agreement, we identified the following three distinct performance obligations:

We considered the manufacturing capabilities of Pfizer and the fact that manufacturing services are not proprietary and can be provided by another third party to conclude that the license has stand-alone functionality and is distinct. Further, the development activities and the supply of API are distinct because Pfizer or another third party could provide these items without our assistance.

We determined the transaction price for the Pfizer Vupanorsen License Agreement to be $250.0 million comprised of the upfront payment we received. None of the development or regulatory milestone payments under this agreement were included in the upfront transaction price as all future payments were fully constrained.

Based on the distinct performance obligations under the Pfizer Vupanorsen License Agreement, we allocated the $250.0 million transaction price based on the relative stand-alone selling prices of each of our performance obligations as follows:

We are recognizing revenue related to each of our performance obligations as follows:

•

We recognized the full amount related to the license and related know-how in the fourth quarter of 2019 because Pfizer, upon the date of closing, had full use of the license and related know-how without any continuing involvement from us. Additionally, we did not have any further performance obligations related to the license after the license was transferred to Pfizer;

•

We are satisfying the development services performance obligation for vupanorsen as the research and development services are performed. The development services performance obligation consists of us completing the Phase 2 clinical trial in non-alcoholic fatty liver disease. We expect development services related to this trial to be completed by mid-2020. We recognize revenue related to development services performed using an input method by calculating costs incurred to date at each period end relative to total costs expected to be incurred. Pfizer is responsible for conducting and funding all future development, regulatory and commercialization activities for vupanorsen once we complete the Phase 2 program; and

In addition, we are eligible to receive up to $1.3 billion in milestone payments, including up to $205.0 million for the achievement of development milestones, up to $250.0 million for the achievement of regulatory milestones and up to $850.0 million for the achievement of commercialization milestones. We will achieve the next milestone payment of $75.0 million when Pfizer advances vupanorsen_. We are also eligible to receive tiered royalties in the mid-teens to low twenty percent range on net sales of vupanorsen. Pfizer will reduce these royalties upon the expiration of certain patents or if a generic competitor negatively impacts the product in a specific country. We will share any milestone payments and royalties equally with Ionis.

During the three months ended March 31, 2020, we recognized $0.6 million of revenue that was in our beginning deferred revenue balance. Our condensed consolidated balance sheet at March 31, 2020 and December 31, 2019 included deferred revenue of $0.7 million and $1.3 million, respectively, related to our development services obligation under the Pfizer Vupanorsen License Agreement.