8-K

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):  March 21, 2006

United Therapeutics Corporation

(Exact Name of Registrant as Specified in Charter)

Delaware	000-26301	52-1984749
(State or Other	(Commission	(I.R.S. Employer
Jurisdiction of	File Number)	Identification Number)
Incorporation)

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:

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

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

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

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

Item 8.01.  Other Events.

On March 21, 2006, United Therapeutics Corporation issued a press release announcing that the United States Food and Drug Administration (FDA) has approved a supplemental New Drug Application (sNDA) for Remodulin^® (treprostinil sodium) Injection in satisfaction of the FDA’s Subpart H accelerated approval requirement for a Phase 4 post-marketing study to confirm the clinical benefit of Remodulin.  A copy of this press release is attached hereto as Exhibit 99.1.

 Item 9.01.  Exhibits

(d)  Exhibits

Exhibit No.	Description of Exhibit
99.1	Press release dated March 21, 2006

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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: March 21, 2006		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 March 21, 2006

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EX-99.1

Exhibit 99.1

For Immediate Release

For Further Information Contact:

Andrew Fisher at (301) 608-9292

Email: Afisher@unither.com

UNITED THERAPEUTICS ANNOUNCES FDA APPROVAL OF

EXPANDED LABEL INDICATION AND SATISFACTION OF

SUBPART H ACCELERATED APPROVAL COMMITMENT

Silver Spring, MD and Research Triangle Park, NC, March 21, 2006:  United Therapeutics Corporation (NASDAQ:UTHR) announced today that the United States Food and Drug Administration (FDA) has approved a supplemental New Drug Application (sNDA) for Remodulin^® (treprostinil sodium) Injection.  The sNDA was filed by United Therapeutics in satisfaction of the FDA’s Subpart H accelerated approval requirement for a Phase 4 post-marketing study to confirm the clinical benefit of Remodulin.  The initial approvals of both subcutaneous and intravenous use of Remodulin were contingent upon United Therapeutics’ completion of that study.

The Phase 4 study, which was successfully completed last year, involved the transition of patients from Flolan to either Remodulin or placebo.  In the trial, 13 of 14 patients (93%) randomized to Remodulin were able to successfully transition from Flolan and complete the study without the need to re-institute Flolan therapy, compared to only 1 of 8 patients (13%) randomized to placebo (p = 0.0002).

“We are pleased to have successfully completed our Subpart H accelerated approval efficacy commitment,” said Roger A. Jeffs, Ph.D., President and Chief Operating Officer of United Therapeutics.  “This study confirms the clinical benefit of Remodulin in pulmonary arterial hypertension patients, provides expanded labeling specific to Flolan transition, and removes Remodulin’s conditional approval status.”

Based on these positive Phase 4 study results, the FDA has expanded Remodulin’s labeling to include the following:  “Remodulin is indicated to diminish the rate of clinical deterioration in patients requiring transition from Flolan; the risks and benefits of each drug should be carefully considered prior to transition.”  Previously, Remodulin had been approved as a continuous subcutaneous infusion or intravenousinfusion (for those not able to tolerate a subcutaneous infusion) for the treatment of pulmonary arterial hypertension in patients with NYHA Class II-IV symptoms to diminish symptoms associated with exercise.

In clinical trials, the most common side effects reported with subcutaneous Remodulin therapy included infusion site pain (85%) and infusion site reaction (83%).  Infusion site symptoms were sometimes severe (39%), and could require prescription narcotics (32%), or could lead to discontinuation of Remodulin (7%).  Other adverse events included headache (27%), diarrhea (25%), nausea (22%), rash (14%), jaw pain (13%),

vasodilatation (11%), dizziness (9%), edema (9%), pruritus (8%) and hypotension (4%).   Among patients (n=38) treated for 12-weeks with intravenous Remodulin in an open-label study, two patients experienced either line infections or sepsis.  Other events potentially related to the mode of infusion include arm swelling, paresthesias, hematoma and pain.  Remodulin is a potent pulmonary and systemic vasodilator and should be used only by clinicians experienced in the diagnosis and treatment of pulmonary arterial hypertension.  Reduction in blood pressure caused by Remodulin may be exacerbated by drugs that by themselves alter blood pressure, such as diuretics, antihypertensive agents, or vasodilators.  Abrupt cessation or sudden large reductions in dosage of Remodulin may result in worsening of pulmonary arterial hypertension symptoms and should be avoided.

United Therapeutics is a biotechnology company focused on the development and commercialization of innovative therapeutic products for patients with chronic and life-threatening cardiovascular, cancer and infectious diseases.