argenx reports full year 2019 financial results and provides fourth quarter business update - Topline data from Phase 3 ADAPT trial of efgartigimod in gMG expected in mid-2020 - Continued progress across broadest FcRn an

argenx reports full year 2019

financial results and provides fourth quarter business update

- Topline data from Phase 3 ADAPT trial of efgartigimod in gMG expected in mid-2020

- Continued progress across broadest FcRn antagonist pipeline with up to five Phase 3 trials to be ongoing in 2020

- Ended 2019 well-capitalized to advance late-stage pipeline with 1.3 billion in cash, cash equivalents and current financial assets

Breda, the Netherlands / Ghent, Belgium - argenx (Euronext & Nasdaq: ARGX), a clinical-stage biotechnology company

developing a deep pipeline of differentiated antibody-based therapies for the treatment of severe autoimmune diseases and cancer,

today announced its financial results for the full year 2019 and provided a fourth quarter business update and outlook for 2020.

"The significant achievements we

made throughout 2019 have provided the foundation for us to execute yet another exciting year ahead as we advance our argenx

2021' vision to become a global, integrated immunology company," commented Tim Van Hauwermeiren, CEO of argenx. "We

are progressing our entire FcRn pipeline across four indications with a fifth to be announced this year and are planning for

a 2021 launch of efgartigimod in gMG, which could be the first approved FcRn antagonist."

"We continue to build innovation

into every step of our development, highlighted by our collaborative Innovative Access Program translating immunology breakthroughs

into medicines, our unique trial designs incorporating input from our patients, and our integrated commercial thinking with the

launch of the first real-world evidence study in MG. We have demonstrated our ability to perform across our late-stage pipeline

and will prioritize maintaining this reputation for execution in 2020 with up to five registrational trials to be ongoing."

FOURTH QUARTER 2019 AND RECENT HIGHLIGHTS

argenx continues to execute on its "argenx

2021" vision to become a fully integrated, global immunology company, which includes the building of two initial commercial

franchises in neuromuscular disorders and hematology/oncology and the expanding of its global presence to support its anticipated

first commercial launch of efgartigimod in 2021.

Efgartigimod: First-in-class opportunity

across range of high-value autoimmune indications

Efgartigimod is a human IgG1 Fc fragment

engineered for optimal blocking of FcRn and targeted reduction of IgG autoantibodies. argenx expects to have up to five registrational

trials ongoing in 2020. Efgartigimod is currently being evaluated in four targeted indications where IgG autoantibodies are directly

pathogenic, including:

argenx has established proof-of-concept

in all three beachhead indications in neuromuscular disorders, hematology and dermatology therapeutic areas for efgartigimod.

Cusatuzumab: First-in-class opportunity

with potential in hematological malignancies

Cusatuzumab is an anti-CD70 monoclonal

antibody being developed under an exclusive global collaboration and license agreement with Janssen for the treatment of acute

myeloid leukemia (AML), high-risk myelodysplastic syndromes (MDS) and other hematological malignancies.

ARGX-117: First-in-class anti-C2 antibody expected to enter clinic in first quarter 2020

ARGX-117 is a complement-targeting antibody

against C2 with potential therapeutic applications in multiple autoimmune diseases.

Early-stage Pipeline

argenx continues to expand its early-stage

pipeline with first-in-class antibodies against immunologic targets:

YEAR 2019 FINANCIAL RESULTS (CONSOLIDATED)

DETAILS OF THE FINANCIAL RESULTS

Cash, cash equivalents and current financial assets totaled

1,335.8 million for the year ended December 31, 2019, compared to 564.6 million for the year ended December 31, 2018.

The increase in the year-end cash balance on December 31, 2019 resulted primarily from (i) the closing of the collaboration and

license agreement for cusatuzumab with Janssen which resulted in a $300 million upfront payment and a $200 million equity investment

in January 2019, and (ii) 479.0 million of net proceeds received from the global offering in November 2019.

Operating income increased by 53.4

million for the year ended December 31, 2019 to 82.6 million, compared to 29.2 million for the year ended December

31, 2018. The increase primarily related to (i) the partial recognition of the upfront payment and the recognition of research

and development service fees under the collaboration and license agreement for cusatuzumab with Janssen and (ii) the recognition

of the milestone payment following the initiation of a first-in-human clinical trial with ABBV-151 under the AbbVie collaboration.

Research and development expenses

totaled 197.7 million and 83.6 million for the years ended December 31, 2019 and 2018, respectively. The increase

is mainly the result of (i) increased external research and development expenses reflecting higher clinical trial costs and

manufacturing expenses related to the development of argenx's product candidate portfolio and (ii) higher personnel

expenses as a result of increased costs of the share-based payment compensation plans related to the grant of stock options

to its research and development employees and increased costs associated with additional research and development

Selling, general and administrative expenses totaled 64.6

million and 27.5 million for the years ended December 31, 2019 and 2018, respectively. The increase of 37.1 million

was principally due to an increase of personnel expense, resulting from (i) higher costs of the share-based payment compensation

plans related to the grant of stock options to argenx's selling, general and administrative employees and (ii) increased

costs associated with additional employees recruited to strengthen its selling, general and administrative activities, notably

in preparation of the potential commercial launch of efgartigimod in the U.S.

For the year ended December 31, 2019, financial income amounted

to 14.4 million compared to 3.7 million for the year ended December 31, 2018. The increase of 10.7 million primarily

related to an increase in the interest received on argenx's cash, cash equivalents and current financial assets.

Exchange gains totaled 6.1 million

for the year ended December 31, 2019 compared to 12.3 million for the year ended December 31, 2018 and were mainly attributable

to unrealized exchange rate gains on argenx's cash, cash equivalents and current financial assets position in U.S. dollars

due to the favorable fluctuation of the EUR/USD exchange rate.

The total comprehensive loss for the year

ended December 31, 2019 was 163.0 million compared to 66.6 million for the year ended December 31, 2018.

US SEC and statutory Financial Reporting

argenx's primary accounting standard

for quarterly earnings releases and annual reports is International Financial Reporting Standards (IFRS) as issued by the International

Accounting Standards Board (IASB). Quarterly summarized statements of profit and loss based on IFRS as issued by the IASB are

available on www.argenx.com.

In addition to reporting financial figures

in accordance with IFRS as issued by the IASB, argenx also reports financial figures in accordance with IFRS as adopted by the

EU for statutory purposes. The consolidated statement of financial position, the consolidated statements of profit and loss, the

consolidated statements of cashflow, and the consolidated statement of changes in equity are not affected by any differences between

IFRS as issued by the IASB and IFRS as adopted by the EU.

The consolidated statement of profit and

loss data of argenx SE as of December 31, 2019, as presented in this press release is unaudited.

argenx will publish its 2019

Annual Report based on IFRS as issued by the IASB and its 2019 Annual Report for statutory purposes based on IFRS as adopted by

the EU on March 24, 2020. These Annual Reports will be available on www.argenx.com.

EXPECTED 2020 FINANCIAL CALENDAR:

CONFERENCE CALL DETAILS

results will be discussed during a conference call and webcast presentation today at 3 pm CET/9 am ET. To participate in the conference

call, please select your phone number below and use the confirmation code 2484158. The webcast may be accessed on the homepage

of the argenx website at www.argenx.com or by clicking here.

Please dial in 5-10 minutes prior

to 3 pm CET/ 9 am ET using the number and conference ID below.

argenx is a global immunology company developing