NCT00139750 is a Phase 2 clinical trial of CP-526,555 (varenicline) in Smoking Cessation, sponsored by Pfizer.

Who is sponsoring NCT00139750?

NCT00139750 is sponsored by Pfizer.

What drugs are being tested in NCT00139750?

Interventions in NCT00139750: CP-526,555 (varenicline).

What condition does NCT00139750 study?

NCT00139750 studies Smoking Cessation.

Is NCT00139750 still recruiting?

NCT00139750 is currently completed. Last updated 1 June 2007.

Last reviewed 2007-06-01 · How we verify

NCT00139750

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

A Double-Blind, Placebo-Controlled, Randomized, Multicenter Study Evaluating The Efficacy And Safety Of CP-526,555 In Smokers Motivated To Stop Smoking

Completed Phase 2 Last updated 1 June 2007

What this trial tests

Phase 2 trial testing CP-526,555 (varenicline) in Smoking Cessation in 600 participants. Completed in 1 February 2006.

Timeline

1 December 2004

1 February 2006

Quick facts

Lead sponsor	Pfizer
Phase	Phase 2
Status	Completed
Study type	INTERVENTIONAL
Allocation	randomized
Design	parallel
Masking	double
Primary purpose	treatment
Enrollment	600
Start date	1 December 2004
Estimated completion	1 February 2006
Sites	15 locations across Japan

Drugs / interventions tested

CP-526,555 (varenicline) — full drug profile →

Conditions studied

Smoking Cessation — all drugs for Smoking Cessation →

Sponsor

Pfizer — full company profile →

Who can join

Adults 20 to 75, any sex, with Smoking Cessation. Patients with the condition only — healthy volunteers not accepted.

What's being measured

Primary outcomes are the specific endpoints the trial is designed to prove or disprove.

4-week continuous quit rate (CQR) for Weeks 9-12

Sponsor's own description

The purpose of the study is to examine the safety and efficacy and dose-response relationship of three doses of CP-526,555 for 12 weeks compared with placebo for smoking cessation; including post-treatment follow-up of smoking status to one year from randomization. A small satellite protocol (A3051048) investigated safety of a second course of therapy in subjects who did not quit.

Publications & conference data

3 peer-reviewed publications reference this trial (live from Europe PMC):

Interventions for preventing weight gain after smoking cessation.
Hartmann-Boyce J, Theodoulou A, Farley A, Hajek P, et al · · 2021 · cited 40× · PMID 34611902 · DOI 10.1002/14651858.cd006219.pub4
Varenicline in smokers with diabetes: A pooled analysis of 15 randomized, placebo-controlled studies of varenicline.
Tonstad S, Lawrence D. · · 2017 · cited 27× · PMID 27223809 · DOI 10.1111/jdi.12543
Predictors of lapse and relapse to smoking in successful quitters in a varenicline post hoc analysis in Japanese smokers.
Nakamura M, Oshima A, Ohkura M, Arteaga C, et al · · 2014 · cited 15× · PMID 24811751 · DOI 10.1016/j.clinthera.2014.03.013

Verify or expand the search:

Other recruiting trials for Smoking Cessation

Currently open trials in the same condition.

NCT07420621 — Preliminary Effectiveness of Enhanced Text Message + Incentives · NA · recruiting
NCT07224087 — Development of a MHBC Intervention for Weight Loss and Smoking Cessation for Pre-Bariatric Surgery Patients · Phase 1 · recruiting
NCT07331519 — Integrating Smoking Cessation With Low-dose CT-screening for Lung Cancer · NA · recruiting
NCT07210567 — Mindfulness-based Ecological Momentary Intervention for Smoking Cessation Among Cancer Survivors · NA · recruiting
NCT07129590 — Trauma-Informed Care for Smoking Cessation for Pregnancy · NA · recruiting

Other Pfizer trials

Trials by the same sponsor.

NCT04982848 — Korea Post Marketing Surveillance (PMS) Study of Talzenna® · not yet recruiting
NCT06873191 — A Study to Learn More About Tukysa Once it is Out in the Korean Market · not yet recruiting
NCT07497854 — A Study to Learn About the Study Medicine NURTEC® ODT 75 mg After it is Released Into the Markets in Korea · not yet recruiting
NCT06507904 — A Study to Learn How Different Preparations of Osivelotor Taste and Enter the Blood With Food or Liquids or With an Anta · Phase 1 · not yet recruiting
NCT06864585 — A Study to Learn About the Study Medicine - Zavicefta in Patients With Sepsis or Loss of Kidney Function in Japan · not yet recruiting

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 NCT00139750 (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: 1 June 2007

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/NCT00139750.

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