NCT00422461 is a Phase 2 clinical trial of PF-00489791 in Hypertension, sponsored by Pfizer.

Who is sponsoring NCT00422461?

NCT00422461 is sponsored by Pfizer.

What drugs are being tested in NCT00422461?

Interventions in NCT00422461: placebo, PF-00489791, PF-00489791, PF-00489791.

What condition does NCT00422461 study?

NCT00422461 studies Hypertension.

Is NCT00422461 still recruiting?

NCT00422461 is currently completed. Last updated 11 October 2021.

Are results published for NCT00422461?

Yes — primary outcome results have been posted to ClinicalTrials.gov. See the outcomes section above for details.

Last reviewed 2021-10-11 · How we verify

NCT00422461

Name: Drug Landscape Pharmaceutical Database
Creator: Drug Landscape
Published: 2026-01-01
License: https://creativecommons.org/licenses/by/4.0/

A Dose Finding Study Of PF-00489791 In Patients With Mild To Moderate High Blood Pressure

Completed Phase 2 Results posted Last updated 11 October 2021

What this trial tests

Phase 2 trial testing placebo in Hypertension in 135 participants. Completed in 28 January 2008.

Timeline

27 February 2007

Primary endpoint
28 January 2008

28 January 2008

Quick facts

Lead sponsor	Pfizer
Phase	Phase 2
Status	Completed
Study type	INTERVENTIONAL
Allocation	randomized
Design	parallel
Masking	triple
Primary purpose	treatment
Enrollment	135
Start date	27 February 2007
Primary completion	28 January 2008
Estimated completion	28 January 2008
Sites	20 locations across United States

Drugs / interventions tested

placebo
PF-00489791 — full drug profile →
PF-00489791 — full drug profile →
PF-00489791 — full drug profile →

Conditions studied

Hypertension — all drugs for Hypertension →

Sponsor

Pfizer — full company profile →

Who can join

Adults 18 to 70, any sex, with Hypertension. Patients with the condition only — healthy volunteers not accepted.

Results — posted to ClinicalTrials.gov

Per-arm endpoint measurements with 95% confidence intervals where reported. Source: trial results section.

Change From Baseline in Mean Daytime Systolic Blood Pressure (SBP) as Measured by Ambulatory Blood Pressure Monitoring (ABPM) at Day 28 Primary · From 08:00 to 16:00 hours on Baseline (Day 0, 1 day prior to first double-blind dose of study drug) and Day 28

The ABPM device was automatically programmed to inflate at every 20 minutes from 05:00 until 21:59 hours and from 22:00 to 04:59 hours the device inflated every 60 minutes. 24-hour clock time was used. ABPM was performed in this study on Baseline, Day 1, 14 and 28. Mean daytime SBP was an average of SBP measurements taken between 08:00 and 16:00 hours by ABPM device on the specified time points. In this outcome measure change from baseline in mean daytime SBP at Day 28 is reported.

Group	Value	95% CI
Placebo	1.38	± 1.55
PF-00489791 4 mg	-1.42	± 1.12
PF-00489791 10 mg	-3.28	± 1.08
PF-00489791 20/40 mg	-5.59	± 1.54

Change From Baseline in Mean Daytime Diastolic Blood Pressure (DBP) as Measured by ABPM at Day 28 Secondary · From 08:00 to 16:00 hours on Baseline (Day 0, 1 day prior to first double-blind dose of study drug) and Day 28

The ABPM device was automatically programmed to inflate at every 20 minutes from 05:00 until 21:59 hours and from 22:00 to 04:59 hours the device inflated every 60 minutes. 24-hour clock time was used. ABPM was performed in this study on Baseline, Day 1, 14 and 28. Mean daytime DBP was an average of DBP measurements taken between 08:00 and 16:00 hours by ABPM device on the specified time points. In this outcome measure change from baseline in mean daytime DBP at Day 28 is reported.

Group	Value	95% CI
Placebo	0.73	± 1.09
PF-00489791 4 mg	-1.97	± 0.81
PF-00489791 10 mg	-3.83	± 0.78
PF-00489791 20/40 mg	-6.23	± 1.09

Change From Baseline in Mean 24-Hour SBP and DBP as Measured by ABPM at Day 28 Secondary · Over 24 hours on Baseline (Day 0, 1 day prior to first double-blind dose of study drug) and Day 28

The ABPM device was automatically programmed to inflate at every 20 minutes from 05:00 until 21:59 hours and from 22:00 to 04:59 hours the device inflated every 60 minutes. 24-hour clock time was used. ABPM was performed in this study on Baseline, Day 1, 14 and 28. Mean 24-hour SBP and DBP was an average of SBP and DBP measurements, respectively, taken for 24 hours by ABPM device respectively. In this outcome measure change from baseline in mean 24-hour SBP and DBP at Day 28 is reported.

SBP

Group	Value	95% CI
Placebo	-0.53	± 1.53
PF-00489791 4 mg	-0.40	± 1.47
PF-00489791 10 mg	-5.28	± 1.55
PF-00489791 20/40 mg	-3.96	± 1.57

DBP

Group	Value	95% CI
Placebo	-0.13	± 1.07
PF-00489791 4 mg	-1.58	± 1.07
PF-00489791 10 mg	-3.94	± 1.09
PF-00489791 20/40 mg	-4.09	± 1.09

Minimum and Maximum SBP and DBP as Measured by ABPM Over 24 Hours on Baseline, Day 1, 14 and 28 Secondary · Over 24 hours on Baseline (Day 0, 1 day prior to first double-blind dose of study drug), Day 1, 14 and 28

The ABPM device was automatically programmed to inflate at every 20 minutes from 05:00 until 21:59 hours and from 22:00 to 04:59 hours the device inflated every 60 minutes. 24-hour clock time was used. ABPM was performed on Baseline, Day 1, 14 and 28. In this outcome measure maximum and minimum SBP and DBP values recorded by ABPM device over 24 hours on Baseline, Day 1, 14 and 28 are reported.

Maximum SBP: Baseline

Group	Value	95% CI
Placebo	176.65	± 12.38
PF-00489791 4 mg	179.68	± 12.40
PF-00489791 10 mg	184.58	± 15.30
PF-00489791 20/40 mg	177.45	± 15.42

Maximum SBP: Day 1

Group	Value	95% CI
Placebo	173.13	± 12.21
PF-00489791 4 mg	176.67	± 19.60
PF-00489791 10 mg	175.62	± 12.29
PF-00489791 20/40 mg	168.00	± 12.17

Maximum SBP: Day 14

Group	Value	95% CI
Placebo	177.58	± 14.53
PF-00489791 4 mg	177.90	± 21.59
PF-00489791 10 mg	179.60	± 11.75
PF-00489791 20/40 mg	176.52	± 16.68

Maximum SBP: Day 28

Group	Value	95% CI
Placebo	177.33	± 14.54
PF-00489791 4 mg	180.40	± 19.40
PF-00489791 10 mg	177.04	± 14.29
PF-00489791 20/40 mg	174.69	± 12.14

Minimum SBP: Baseline

Group	Value	95% CI
Placebo	117.88	± 11.79
PF-00489791 4 mg	114.38	± 12.65
PF-00489791 10 mg	122.52	± 11.66
PF-00489791 20/40 mg	115.30	± 13.60

Minimum SBP: Day 1

Group	Value	95% CI
Placebo	119.06	± 12.32
PF-00489791 4 mg	110.27	± 14.38
PF-00489791 10 mg	110.21	± 13.46
PF-00489791 20/40 mg	109.38	± 13.30

Minimum SBP: Day 14

Group	Value	95% CI
Placebo	113.82	± 12.76
PF-00489791 4 mg	114.31	± 13.59
PF-00489791 10 mg	114.07	± 11.99
PF-00489791 20/40 mg	111.94	± 10.52

Minimum SBP: Day 28

Group	Value	95% CI
Placebo	117.57	± 15.54
PF-00489791 4 mg	114.27	± 13.66
PF-00489791 10 mg	116.64	± 10.28
PF-00489791 20/40 mg	110.34	± 8.32

Change From Baseline in Cuff SBP and DBP at Day 28 Secondary · Baseline (pre dose value on Day 1 of treatment), Day 28

At Baseline and Day 28 visit, sitting cuff SBP and DBP was measured with the participant's arm supported at the level of the heart. The participant sat with feet flat on the floor for 5 minutes before the first BP was obtained. The BP measurement was done in duplicate approximately 5 minutes apart. The mean of duplicate measurements was recorded.

Cuff SBP

Group	Value	95% CI
Placebo	-4.60	± 1.88
PF-00489791 4 mg	-5.20	± 1.82
PF-00489791 10 mg	-4.97	± 1.89
PF-00489791 20/40 mg	-9.76	± 1.95

Cuff DBP

Group	Value	95% CI
Placebo	-1.33	± 1.27
PF-00489791 4 mg	-4.37	± 1.22
PF-00489791 10 mg	-5.82	± 1.27
PF-00489791 20/40 mg	-5.63	± 1.30

Change From Baseline in Cuff SBP and DBP at Day 31 Secondary · Baseline (pre dose value on Day 1 of treatment), Day 31

At Baseline and Day 31 visit, sitting cuff SBP and DBP was measured with the participant's arm supported at the level of the heart. The participant sat with feet flat on the floor for 5 minutes before the first BP was obtained. The BP measurement was done in duplicate approximately 5 minutes apart. The mean of duplicate measurements was recorded.

Cuff SBP

Group	Value	95% CI
Placebo	0.4	± 10.18
PF-00489791 4 mg	-0.6	± 11.39
PF-00489791 10 mg	-0.3	± 10.96
PF-00489791 20/40 mg	0.4	± 13.07

Cuff DBP

Group	Value	95% CI
Placebo	-0.7	± 6.76
PF-00489791 4 mg	-0.2	± 7.47
PF-00489791 10 mg	-0.8	± 7.58
PF-00489791 20/40 mg	0.3	± 7.86

Change From Baseline in Cuff Mean Arterial Pressure (MAP) at Day 28 Secondary · Baseline (pre dose value on Day 1 of treatment), Day 28

At Baseline and Day 28, sitting cuff MAP was measured with the participant's arm supported at the level of the heart. The participant sat with feet flat on the floor for 5 minutes before the first MAP was obtained. The MAP measurement was done in duplicate approximately 5 minutes apart. The mean of duplicate measurements was recorded.

Group	Value	95% CI
Placebo	-2.59	± 1.29
PF-00489791 4 mg	-4.54	± 1.26
PF-00489791 10 mg	-5.53	± 1.31
PF-00489791 20/40 mg	-7.06	± 1.34

Number of Participants With Treatment-Emergent Adverse Events (TEAEs) and Serious Adverse Events (SAEs) Secondary · Day 1 up to 14 days after last dose of study drug (maximum up to 42 days)

An adverse event (AE) was any untoward medical occurrence in a participant who received study drug without regard to possibility of causal relationship. An SAE was an AE resulting in any of the following outcomes or deemed significant for any other reason: death; initial or prolonged inpatient hospitalization; life-threatening experience (immediate risk of dying); persistent or significant disability/incapacity; congenital anomaly. Treatment-emergent AEs are events between first dose of study drug and up to 14 days after last dose that were absent before treatment or that worsened relative to

TEAEs

Group	Value	95% CI
Placebo	12
PF-00489791 4 mg	11
PF-00489791 10 mg	11
PF-00489791 20/40 mg	13

SAEs

Group	Value	95% CI
Placebo	1
PF-00489791 4 mg	1
PF-00489791 10 mg	0
PF-00489791 20/40 mg	0

Number of Participants With Clinically Significant Laboratory Abnormalities Secondary · Day 1 up to 14 days after last dose of study drug (maximum up to 42 days)

Criteria for laboratory abnormalities included: hemoglobin, hematocrit, red blood cell count, total neutrophils, total protein, albumin: \<0.8\* limit of normal (LLN). Platelets: less than (\<)0.5\* LLN, greater than (\>)1.75\* upper limit of normal (ULN); white blood cell, glucose: \<0.6\*LLN, \>1.5\*ULN, lymphocytes: \<0.8\*LLN; \>1.2\*ULN; basophils, monocytes, eosinophils, total protein, albumin, uric acid: \>1.2\*ULN; aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase: \>3.0\*ULN; blood urea nitrogen, creatinine: \>1.3\*ULN; sodium: \<0.95\*LLN, \>1.05\*ULN; potass

Group	Value	95% CI
Placebo	10
PF-00489791 4 mg	9
PF-00489791 10 mg	11
PF-00489791 20/40 mg	10

Change From Baseline in Heart Rate at Baseline, Day 1, 7, 14, 21, 28 and 31 Secondary · Baseline (pre dose value on Day 1 of treatment), Day 1, 7, 14, 21, 28, 31

Sitting heart rate was measured with the participant's arm supported at the level of the heart. The participant sat with feet flat on the floor for 5 minutes before the heart rate was measured. The heart rate was measured for a minimum of 30 seconds, and the average of two measurements was recorded. Heart rate was measured in beats per minute.

Baseline

Group	Value	95% CI
Placebo	71.5	± 8.76
PF-00489791 4 mg	69.2	± 8.43
PF-00489791 10 mg	67.9	± 8.63
PF-00489791 20/40 mg	68.3	± 7.90

Change at Day1

Group	Value	95% CI
Placebo	0.5	± 6.04
PF-00489791 4 mg	1.8	± 6.64
PF-00489791 10 mg	4.8	± 7.42
PF-00489791 20/40 mg	5.7	± 8.14

Change at Day 7

Group	Value	95% CI
Placebo	-0.3	± 5.92
PF-00489791 4 mg	1.5	± 7.44
PF-00489791 10 mg	3.2	± 9.60
PF-00489791 20/40 mg	4.6	± 8.47

Change at Day 14

Group	Value	95% CI
Placebo	-1.2	± 5.35
PF-00489791 4 mg	-0.1	± 8.08
PF-00489791 10 mg	1.6	± 8.23
PF-00489791 20/40 mg	4.0	± 7.15

Change at Day 21

Group	Value	95% CI
Placebo	0.5	± 7.27
PF-00489791 4 mg	2.9	± 9.18
PF-00489791 10 mg	-0.3	± 8.55
PF-00489791 20/40 mg	4.9	± 8.70

Change at Day 28

Group	Value	95% CI
Placebo	-0.0	± 7.77
PF-00489791 4 mg	0.5	± 7.78
PF-00489791 10 mg	0.8	± 9.31
PF-00489791 20/40 mg	3.4	± 9.38

Change at Day 31

Group	Value	95% CI
Placebo	-1.4	± 8.85
PF-00489791 4 mg	-0.3	± 8.17
PF-00489791 10 mg	0.7	± 8.76
PF-00489791 20/40 mg	4.8	± 8.26

Number of Participants With Clinically Significant Electrocardiogram (ECG) Findings Secondary · Day 1 up to 14 days after last dose of study drug (maximum up to 42 days)

Following ECG parameters were evaluated: QT interval, QTc interval, RR interval, PR interval, QRS complex and heart rate. Clinical significant ECG findings were determined by the investigator's discretion.

Group	Value	95% CI
Placebo	1
PF-00489791 4 mg	0
PF-00489791 10 mg	0
PF-00489791 20/40 mg	0

Adverse events — posted to ClinicalTrials.gov

Time frame: Day 1 up to 14 days after last dose of study drug (maximum up to 42 days). Reporting threshold: 0%. Adverse-event reports describe events observed during the trial — not all are caused by the drug.

Placebo

Serious: 1/34 (3%)

Deaths: 0/34

PF-00489791 4 mg

Serious: 1/34 (3%)

Deaths: 0/34

PF-00489791 10 mg

Serious: 0/32 (0%)

Deaths: 0/32

PF-00489791 20/40 mg

Serious: 0/33 (0%)

Deaths: 0/33

Serious adverse events (2 terms)

Reaction	System	Placebo	PF-00489791 4 mg	PF-00489791 10 mg	PF-00489791 20/40 mg
Post-traumatic stress disorder	Psychiatric disorders	—	—	—	—
Stomach discomfort	Gastrointestinal disorders	—	—	—	—

Other adverse events (53 terms — click to expand)

Reaction	System	Placebo	PF-00489791 4 mg	PF-00489791 10 mg	PF-00489791 20/40 mg
Headache	Nervous system disorders	—	—	—	—
Dyspepsia	Gastrointestinal disorders	—	—	—	—
Back pain	Musculoskeletal and connective tissue disorders	—	—	—	—
Oedema peripheral	General disorders	—	—	—	—
Arthralgia	Musculoskeletal and connective tissue disorders	—	—	—	—
Diarrhoea	Gastrointestinal disorders	—	—	—	—
Gastrooesophageal reflux disease	Gastrointestinal disorders	—	—	—	—
Pain in extremity	Musculoskeletal and connective tissue disorders	—	—	—	—
Dizziness	Nervous system disorders	—	—	—	—
Hypoaesthesia	Nervous system disorders	—	—	—	—
Rash	Skin and subcutaneous tissue disorders	—	—	—	—
Left ventricular hypertrophy	Cardiac disorders	—	—	—	—
Dry eye	Eye disorders	—	—	—	—
Eyelid oedema	Eye disorders	—	—	—	—
Ocular hyperaemia	Eye disorders	—	—	—	—
Retinal haemorrhage	Eye disorders	—	—	—	—
Constipation	Gastrointestinal disorders	—	—	—	—
Dysphagia	Gastrointestinal disorders	—	—	—	—
Mucous stools	Gastrointestinal disorders	—	—	—	—
Nausea	Gastrointestinal disorders	—	—	—	—
Vomiting	Gastrointestinal disorders	—	—	—	—
Chest pain	General disorders	—	—	—	—
Fatigue	General disorders	—	—	—	—
Pyrexia	General disorders	—	—	—	—
Bronchitis	Infections and infestations	—	—	—	—
Conjunctivitis infective	Infections and infestations	—	—	—	—
Eye infection	Infections and infestations	—	—	—	—
Gastroenteritis	Infections and infestations	—	—	—	—
Nasopharyngitis	Infections and infestations	—	—	—	—
Upper respiratory tract infection	Infections and infestations	—	—	—	—
Urinary tract infection	Infections and infestations	—	—	—	—
Viral labyrinthitis	Infections and infestations	—	—	—	—
Blood pressure increased	Investigations	—	—	—	—
White blood cells urine positive	Investigations	—	—	—	—
Increased appetite	Metabolism and nutrition disorders	—	—	—	—
Muscle spasms	Musculoskeletal and connective tissue disorders	—	—	—	—
Musculoskeletal pain	Musculoskeletal and connective tissue disorders	—	—	—	—
Myalgia	Musculoskeletal and connective tissue disorders	—	—	—	—
Neck pain	Musculoskeletal and connective tissue disorders	—	—	—	—
Dizziness postural	Nervous system disorders	—	—	—	—

Most-reported serious reactions: Post-traumatic stress disorder, Stomach discomfort.

Data from ClinicalTrials.gov NCT00422461 adverse events section.

Sponsor's own description

The purpose of this study is to evaluate the safety and blood pressure lowering effect of different doses of PF-00489791 in patients with mild to moderate high blood pressure

Publications & conference data

1 peer-reviewed publication reference this trial (live from Europe PMC):

Established and emerging therapeutic uses of PDE type 5 inhibitors in cardiovascular disease.
Tzoumas N, Farrah TE, Dhaun N, Webb DJ. · · 2020 · cited 71× · PMID 31721165 · DOI 10.1111/bph.14920

Verify or expand the search:

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Verify against primary sources

ClinicalTrials.gov — authoritative US registry record
WHO ICTRP — international registry index
EU Clinical Trials Register
Sponsor press releases (Google)

Data sources for this page

Trial protocol + status: ClinicalTrials.gov NCT00422461 (US National Library of Medicine, public domain)
Publications: Europe PMC API search by NCT ID, retrieved 10 June 2026
Drug + disease cross-links: matched in real time against Drug Landscape's normalised drug + company + condition tables
Sponsor: as reported to ClinicalTrials.gov by Pfizer
Last refreshed: 11 October 2021

Drug Landscape aggregates and links these public records for informational use only. Always verify against the primary source before clinical or regulatory decisions. Canonical URL: https://druglandscape.com/trial/NCT00422461.

Primary sources · FDA · ClinicalTrials.gov · EMA · SEC EDGAR · ChEMBL · Wikidata · full sourcing