The meta-analysis in the December 3 edition of JAMA looks set to reignite debate about the value of brandname medicines where generic equivalents are available.
JAMA notes that a number of editorials have suggested that that doctors should not consider generics and branded medicines interchangeable, even though the generic has been deemed ‘bioequivalent’ by the US Food and Drug Administration (FDA).
“There is concern among patients and physicians that brand-name drugs may be clinically superior to generic drugs,” said the authors, headed by William Shrank of Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts.
Conceptually, some patients and even some doctors have difficulty believing that a generic that costs a tenth of the cost of the brandname version can be as effective, even though the FDA has reviewed and approved a data dossier indicating just that.
But “evidence does not support the notion that brand-name drugs used in cardiovascular disease are superior to generic drugs,” conclude the authors.
They looked at 47 articles covering nine subclasses of cardiovascular medications in their analysis, and found that in almost all cases the generics performed as well as the branded medicines in randomised clinical trials.
Clinical equivalence was seen in seven of seven studies on beta-blockers, 10 of 11 trials involving diuretics, and five of seven trials of calcium channel blockers. Similarly, 100 per cent of the studies of antiplatelet agents, angiotensin-converting enzyme (ACE) inhibitors, and alpha-blockers found the drugs were interchangeable.
The same applied for drug with a narrow therapeutic index drugs. Clinical equivalence was reported in one trial involving class 1 antiarrhythmic agents and five out of five trials of warfarin.
Despite this body of clinical evidence, the authors say that a majority (53 per cent) of 43 editorials reviewed in the analysis expressed a negative view of generic drug substitution.
Ken Johnson, senior vice president of industry body Pharmaceutical Research and Manufacturers of America (PhRMA), said that the idea that brandname medicines drive up the cost of medicines is “fatally flawed.”
“The US already has one of the highest rates of generic drug use in developed countries,” he pointed out, with nearly seven out of every 10 prescriptions filled with a generic drug according to IMS data.