8-K

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15 (d) of the

Securities Exchange Act of 1934

Date of Report (Date of earliest event reported):  April 28, 2009

United Therapeutics Corporation

(Exact Name of Registrant as Specified in Charter)

Delaware (State or Other Jurisdiction of Incorporation)	000-26301 (Commission File Number)	52-1984749 (I.R.S. Employer Identification Number)
1110 Spring Street
Silver Spring, MD		20910
(Address of Principal Executive Offices)		(Zip Code)

Registrant’s telephone number, including area code:

(301) 608-9292

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

o Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

o Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

o Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

o Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Item 7.01.  Regulation FD Disclosure.

On April 28, 2009, United Therapeutics Corporation (the “Company”) issued a press release regarding a 90-day extension of the U.S. Food and Drug Administration’s pending review of its New Drug Application for inhaled treprostinil (Tyvaso).  A copy of the press release is attached hereto as Exhibit 99.1.

The information contained in this Current Report on Form 8-K, including Exhibit 99.1 attached hereto, shall not be deemed to be “filed” for the purposes of Section 18 of the Securities Exchange Act of 1934, as amended, or otherwise subject to liability under that section, nor shall it be deemed incorporated by reference into any filing under the Securities Act of 1933, as amended, except as shall be expressly set forth by specific reference in such filing.

Item 9.01.  Exhibits

(d)  Exhibits

Exhibit No.	Description of Exhibit
99.1	Press release dated April 28, 2009

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SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

	UNITED THERAPEUTICS CORPORATION
Dated: April 28, 2009	By:	/s/ Paul A. Mahon
	Name:	Paul A. Mahon
	Title:	General Counsel

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Exhibit Index

Exhibit No.	Description of Exhibit
99.1	Press release dated April 28, 2009

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EX-99.1

Exhibit 99.1

For Immediate Release

Contact: Andrew Fisher

(202) 483-7000

Afisher@unither.com

U.S. FOOD AND DRUG ADMINISTRATION EXTENDS ACTION DATE FOR INHALED TREPROSTINIL (TYVASO) NEW DRUG APPLICATION BY

THREE MONTHS

Silver Spring, MD, April 28, 2009:  United Therapeutics Corporation (NASDAQ: UTHR) announced today that the U.S. Food and Drug Administration (FDA) will require additional time to complete its review of the New Drug Application (NDA) for Tyvaso™ (inhaled treprostinil).  In a notice received today, the FDA extended the Prescription Drug User Fee Act (PDUFA) date from April 30, 2009, to July 30, 2009.  United Therapeutics previously disclosed the likelihood of this delay in a press release dated March 16, 2009.

The three-month extension was triggered by United Therapeutics’ April 2009 submission to the FDA of the results of a human factors study, which was considered a major amendment to the NDA.  In March 2009, the FDA notified United Therapeutics that it required human factors testing to validate the instructions for use of the Optineb® nebulizer in order to complete its evaluation of the Tyvaso NDA. “We look forward to working with the FDA as it completes its review of our human factors study submission,” said Roger Jeffs, Ph.D., United Therapeutics’ President and Chief Operating Officer.  “We made every effort to conduct and submit the study as quickly as possible.”

“We are most appreciative of the FDA’s input as we work toward our goal of bringing Tyvaso to market,” said Martine Rothblatt, Ph.D., United Therapeutics’ Chairman and Chief Executive Officer. “This news will provide considerable hope to the thousands of pulmonary hypertension patients struggling with existing treatments.”

About United Therapeutics

United Therapeutics Corporation is a biotechnology company focused on the development and commercialization of unique products to address the unmet medical needs of patients with chronic and life-threatening cardiovascular and infectious diseases and cancer.

 Forward-looking Statements

Statements included in this press release concerning the FDA’s pending review of our Tyvaso NDA, the expected duration of such review and our goal of bringing Tyvaso to market are “forward-looking statements” within the meaning of the safe harbor contained in the Private Securities Litigation Reform Act of 1995. These forward-looking statements are qualified by the cautionary statements, cautionary language and risk factors set forth in our periodic reports and documents filed with the Securities and Exchange Commission, including our most recent Annual Report on Form 10-K, Quarterly Reports on Form 10-Q, and current reports on Form 8-K, which could cause actual results to differ materially from anticipated results.  We are providing this information as of April 28, 2009, and assume no obligation to update or revise the information contained in this press release whether as a result of new information, future events or any other reason. [uthr-g]

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