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Sildenafil Therapy for Pulmonary Hypertension and Sickle Cell Disease

This study has been terminated.
(Subjects on drug were more likely to have severe pain crises requiring hospitalization.)
Information provided by (Responsible Party):
Mark Gladwin, National Heart, Lung, and Blood Institute (NHLBI) Identifier:
First received: June 26, 2007
Last updated: December 7, 2015
Last verified: December 2015
Results First Received: April 28, 2011  
Study Type: Interventional
Study Design: Allocation: Randomized;   Intervention Model: Parallel Assignment;   Masking: Double Blind (Participant, Investigator);   Primary Purpose: Treatment
Conditions: Sickle Cell Disease
Pulmonary Hypertension
Interventions: Drug: Sildenafil
Drug: Placebo

  Participant Flow

  Baseline Characteristics
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Population Description
Explanation of how the number of participants for analysis was determined. Includes whether analysis was per protocol, intention to treat, or another method. Also provides relevant details such as imputation technique, as appropriate.
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Reporting Groups
Sildenafil Subjects received oral sildenafil 20 mg three times daily for six weeks, followed by 40 mg three times daily for four weeks, followed by 80 mg three times daily for six weeks (as tolerated).
Placebo Subjects received matching oral dose of placebo 20 mg three times daily for six weeks, followed by 40 mg three times daily for four weeks, followed by 80 mg three times daily for six weeks (as tolerated).
Total Total of all reporting groups

Baseline Measures
   Sildenafil   Placebo   Total 
Overall Participants Analyzed 
[Units: Participants]
 37   37   74 
[Units: Years]
Mean (Standard Deviation)
 47  (13)   44  (14)   45  (13) 
[Units: Participants]
Female   23   23   46 
Male   14   14   28 
Ethnicity (NIH/OMB) 
[Units: Participants]
Hispanic or Latino   0   0   0 
Not Hispanic or Latino   32   37   69 
Unknown or Not Reported   5   0   5 
Race (NIH/OMB) 
[Units: Participants]
American Indian or Alaska Native   0   0   0 
Asian   0   0   0 
Native Hawaiian or Other Pacific Islander   0   0   0 
Black or African American   36   37   73 
White   0   0   0 
More than one race   0   0   0 
Unknown or Not Reported   1   0   1 
6 minute walk [1] 
[Units: Meters]
Mean (Standard Deviation)
 381  (75)   386  (75)   383  (75) 
[1] The distance walked in six minute was used to assess the exercise capacity of the patient at baseline.
Tricuspid regurgitant jet velocity (TRV) [1] 
[Units: M/s]
Mean (Standard Deviation)
 3.0  (0.5)   3.0  (0.3)   3.0  (0.3) 
[1] Tricuspid regurgitant jet velocity was measured by transthoracic Doppler Echocardiography.

  Outcome Measures
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1.  Primary:   Change in Exercise Capacity as Assessed by 6 Minute Walk.   [ Time Frame: Baseline to week 16/Imputed last visit. ]

2.  Secondary:   Change From Baseline in Pulmonary Hypertension at Week 16 as Assessed by Tricuspid Regurgitant Jet Velocity   [ Time Frame: 16 weeks ]

3.  Secondary:   Borg Dyspnea Score   [ Time Frame: baseline to 16 weeks ]

4.  Secondary:   Brain Natriuretic Peptide(BNP)Levels.   [ Time Frame: 16 weeks ]

  Serious Adverse Events

  Other Adverse Events

  Limitations and Caveats
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Limitations of the study, such as early termination leading to small numbers of participants analyzed and technical problems with measurement leading to unreliable or uninterpretable data
As a result of early termination due to safety findings, the study was underpowered to assess the effects of sildenafil therapy on the predetermined efficacy endpoints.

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