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Dr KATE LLOYD, medical director, Pfizer Ltd, replies:

Mr Burrill accuses Pfizer of misleading and selective reporting in an advertisement concerning the ALLHAT trial. We strongly refute these allegations.

Amlodipine (Istin) in the United Kingdom is licensed for hypertension and is generally prescribed as add-on treatment to other antihypertensive medication.

Hypertension is a well-recognised surrogate for stroke but perhaps less well accepted as a surrogate for generalised cardiovascular morbidity and mortality. It may therefore be considered inappropriate to talk about any outcomes other than stroke in conjunction with amlodipine's effect in lowering blood pressure.

Mr Burril focuses on the heart failure data. In ALLHAT, heart failure was not a primary or secondary endpoint in its own right, but was part of a composite of "combined cardiovascular disease". There was no statistically significant difference between amlodipine and diuretic for this endpoint. In addition, there was no significant difference between amlodipine and diuretic in deaths due to heart failure.

The assertion, that placing patients on amlodipine therapy instead of a thiazide diuretic costs lives, is thus unfounded. As noted above, in this clinical trial, much as in United Kingdom clinical practice, approximately two-thirds of patients will be on combination medication rather than monotherapy to achieve blood pressure control to target.

A recent editorial in the BMJ¹ has reviewed the ALLHAT results. Pfizer's conclusions from the ALLHAT trial appear to be in line with the views of the editorial, which also comments: This finding [increased incidence of heart failure in the ACE inhibitor and calcium channel blocker arms of ALLHAT] must be viewed with caution. It is not surprising that patients randomised to diuretic got less oedema than those randomised to ACE inhibitor or calcium channel blocker."

It is for these reasons that we believe that our advertising represents a fair balance of the clinical outcomes of the ALLHAT study that we can discuss in the context of amlodipine promotion. Amlodipine, when used within its licence and according to its clinical data is a valuable drug in the treatment of hypertension.