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Another Hypertension Trial: Verapamil vs. Hydrochlorothiazide or Atenolol

Therapy with a calcium-channel blocker, a diuretic, or a ß-blocker yielded similar outcomes. But was it appropriate to stop the trial early?

Results from the ALLHAT study reinforced the idea that diuretics should remain the standard of comparison for initial antihypertensive therapy (Journal Watch Jan 14 2003). Now, investigators report results from an industry-sponsored, multicenter, randomized trial (the CONVINCE trial) in which a controlled-onset, extended-release form of the calcium-channel blocker verapamil was examined.

More than 16,000 patients with hypertension and 1 or more additional cardiac risk factors were enrolled. Half received verapamil (180 mg daily); the rest received either hydrochlorothiazide (12.5 mg daily) or atenolol (50 mg daily), according to the investigators' judgment of which would be best for each patient. An algorithm dictated dose changes and addition of other drugs, when necessary.

Although the intended mean follow-up was 5 years, the sponsoring company stopped the trial "for commercial reasons" after a mean follow-up of 3 years. The 3-year incidence of the primary combined endpoint (myocardial infarction, stroke, or cardiovascular death) did not differ significantly between the 2 groups (4.9% with verapamil vs. 4.7% with hydrochlorothiazide/atenolol). Verapamil recipients were significantly more likely to develop heart failure (1.5% vs. 1.2%) and to die or be hospitalized due to bleeding (1.4% vs. 1.0%).

Comment: According to these results, initial antihypertensive therapy with verapamil might be similar -- but certainly is not better -- than initial therapy with a diuretic or a ß-blocker. Editorialists criticize the decision of the sponsoring drug company to terminate the study prematurely: They believe that any chance to generate useful new information was cut short, and that ethical considerations mandate the completion of clinical trials unless clear evidence favoring one treatment emerges while the trial is in progress.

— Allan S. Brett, MD

Published in Journal Watch General Medicine May 13, 2003

Citation(s):

Black HR et al. Principal results of the Controlled ONset Verapamil INvestigation of Cardiovascular End points (CONVINCE) trial. JAMA 2003 Apr 23/30; 289:2073-82.

• Original article (Subscription may be required)
• Medline abstract (Free)

Psaty BM and Rennie D. Stopping medical research to save money: A broken pact with researchers and patients. JAMA 2003 Apr 23/30; 289:2128-31.

• Original article (Subscription may be required)
• Medline abstract (Free)