Cholesterol-Lowering Atherosclerosis Study (CLAS)

December 12, 2013 updated by: National Heart, Lung, and Blood Institute (NHLBI)
To determine whether combined therapy with the lipid lowering agents colestipol hydrochloride plus niacin would produce significant change in coronary, carotid, and femoral artery atherosclerosis and coronary bypass graft lesions as determined by angiography. Also, to determine possible correlations between lesion changes and plasma lipid and lipoprotein cholesterol levels and to explore interrelationships of atherosclerosis change in femoral, coronary, and carotid arteries.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

BACKGROUND:

The Lipid Research Clinics Coronary Primary Prevention Trial and the Coronary Drug Project had shown that morbidity and mortality from ischemic heart disease were reduced by blood cholesterol-lowering therapy. Although blood cholesterol reduction ameliorated experimental atherosclerosis in animal models, the two largest human studies with angiographic observation of arterial lesion change, the NHLBI Type II Coronary Intervention Study and a study by Cohn et al, had not demonstrated significant treatment effects. Favorable, but inconclusive, treatment trends were observed in four unrandomized angiographic trials and one trial too small for evaluation of randomized groups.

The clinical trial was supported by a subproject within a program project grant.

DESIGN NARRATIVE:

CLAS-I was randomized and selectively-blinded. Screening for the trial consisted of five clinic visits, at which baseline data, including angiographic data, were obtained and a prerandomization trial of the study drugs was conducted. One hundred eighty-eighty subjects were randomized to either 30 grams (g) of colestipol hydrochloride plus 3 to 12 g of niacin daily or to placebo. Both groups received diet intervention. The drug group received less than 125 milligrams (mg) of cholesterol daily, 22 percent of energy as fat, 10 percent as polyunsaturated fat, and 4 percent as saturated fat. The placebo group received less than 250 mg of cholesterol per day, 26 percent of energy as fat, 10 percent as polyunsaturated fat, and 5 percent as saturated fat. The different diet composition for drug and placebo groups was to enhance the differential in blood cholesterol responses between the two groups. Study subjects and clinic staff were blinded to the prerandomization study drug trial lipid responses. Subjects were blinded to treatment assignments. Subjects and staff were not blinded to on-trial lipid values. The primary endpoint, the global change score, was change in atherosclerosis observed by angiography of native coronary arteries and aorta coronary bypass grafts. Evaluation of study end-points was performed by staff and consultants who were blinded to treatment group assignments, as well as to the temporal ordering of angiographic data. Subjects were seen monthly for the first six months and then at two-month intervals. A repeat angiogram was performed at two years. Of the 188 randomized subjects, 162 completed the study.

On completion of CLAS-I, participants not requiring further bypass surgery were invited to continue in CLAS-II for an additional two years on their previously assigned treatment. Blinded study methods were maintained; there was no crossover between treatments. One hundred thirty-eight subjects continued in CLAS-II; 103 completed a third angiogram before the CLAS-I outcome was known and CLAS-II terminated. The CLAS-II clinical procedures, lipid, lipoprotein-cholesterol, and apolipoprotein analyses were the same as in CLAS-I. The CLAS-II angiographic and file evaluation procedures exactly replicated those in CLAS-I.

The study completion date listed in this record was obtained from the Query/View/Report (QVR) System.

Study Type

Interventional

Phase

  • Phase 3

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

40 years to 59 years (Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

Male

Description

Non-smoking men, ages 40 to 59, with progressive atherosclerosis confirmed by angiography, who had coronary bypass surgery at least three months prior to the study admission date, and who had entry fasting blood cholesterol levels in the range of 185

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

National Heart, Lung, and Blood Institute (NHLBI)

Investigators

  • Stanley Azen, University of Southern California
  • David Blankenhorn, University of Southern California

Publications and helpful links

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General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

June 1, 1980

Study Completion (Actual)

November 1, 1994

Study Registration Dates

First Submitted

October 27, 1999

First Submitted That Met QC Criteria

October 27, 1999

First Posted (Estimate)

October 28, 1999

Study Record Updates

Last Update Posted (Estimate)

December 13, 2013

Last Update Submitted That Met QC Criteria

December 12, 2013

Last Verified

May 1, 2000

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 502
  • P01HL023619 (U.S. NIH Grant/Contract)

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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