Exhibit 21
SUBSIDIARIES OF THE REGISTRANT
EvoLung Inc., a Delaware Corporation
Lung Bioengineering Inc., a Delaware Corporation
Lung Biotechnology Hong Kong Limited, a Hong Kong Company
Lung Biotechnology Inc., a Delaware Corporation (formerly Lung LLC)
Lung Biotechnology (Nanjing) Co., Ltd., a Chinese Wholly Foreign-Owned Entity
Lung Rx Limited, a United Kingdom Company
Revivicor, Inc., a Delaware Corporation
United Therapeutics Europe, Ltd., a United Kingdom Company
Unither Biotech Inc., a Canadian Corporation
Unither Pharma, LLC, a Delaware Limited Liability Company
Unither Pharmaceuticals, LLC, a Delaware Limited Liability Company
Unither Telmed, Ltd., a Delaware Corporation
Unither Therapeutik GmbH, a German Company
Unither Virology, LLC, a Delaware Limited Liability Company
Unither.com, Inc., a Delaware Corporation
UTASIA Inc., a Delaware Corporation
1109 Spring Managing Holdings, LLC, a Delaware Limited Liability Company
1109 Spring Managing Member, LLC, a Delaware Limited Liability Company