Wednesday, January 24, 2007

BiDiL: is it really an African thing?

Here's an argument against BiDil and a response from the FDA.

BiDil for heart failure in black patients: implications of the U.S. Food and Drug Administration approval.

Ann Intern Med. 2007 Jan 2;146(1):52-6. Bibbins-Domingo K, Fernandez A.

Abstract: In 2005, the combination of hydralazine hydrochloride and isosorbide dinitrate was approved by the U.S. Food and Drug Administration (FDA) for treating heart failure in black patients. In departing from its long history of approving drugs for general clinical indications without regard to demographic classification, the FDA cited the need to address racial disparities in health as an important contributor to their decision. The authors argue that this decision, although perhaps well-intentioned, was based on flawed scientific interpretation of trial results that claimed differential drug response by race and ignored the considerable literature on the cause of racial disparities in health and health care. Because of its potential impact on future drug approvals, the FDA's decision is a setback in the scientific and policy discourse on medical therapeutics and race and specifically hinders the efforts aimed at eliminating health and health care disparities.

BiDil for heart failure in black patients: The U.S. Food and Drug Administration perspective

Temple R, Stockbridge NL.

Ann Intern Med. 2007 Jan 2;146(1):57-62

Abstract: Critics of the U.S. Food and Drug Administration (FDA) approval of the fixed combination of hydralazine hydrochloride, 37.5 mg, and isosorbide dinitrate, 20 mg, for treating heart failure in black patients have suggested that data were insufficient to distinguish treatment effects in black and white people; that distinctions based on race, rather than pathophysiology, were scientifically unreasonable; and that a "race-based" approval could be a commercial ploy to avoid a more expensive and prolonged full evaluation of a drug. The criticisms acknowledge that data supporting the approval came from a well-designed clinical trial in which self-identified black patients with heart failure who took hydralazine hydrochloride-isosorbide dinitrate with standard therapy experienced a statistically significant 43% (95% CI, 11% to 63%) reduction in mortality compared with those who took only the standard therapy. The criticisms do not always recognize that the decision to conduct the trial in only black patients reflected careful analyses of 2 previous trials in racially mixed patient populations that compared hydralazine hydrochloride-isosorbide dinitrate with placebo or with enalapril. Both trials showed little or no overall effect of hydralazine hydrochloride-isosorbide dinitrate in the mostly white patient population but hinted at a substantial effect in subsets of black patients. Perhaps most critically, the criticisms do not appreciate the urgency of strong scientific evidence of a substantial survival benefit in black patients. A serious attempt to avoid race-based approval by mandating study of a mixed population to identify a possible white patient-responder subset, particularly without a plausible hypothesis as to what that subset might be, would have required years of work, many thousands of patients, and wholly unreasonable delay in approval of a treatment whose effectiveness had been well-documented in the group for which it was intended.


1 comment:

Hank said...

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