Tuesday, May 19, 2009

Studies--but not Editorials--Confirm Generic Equivalence

Playing catch-up on a study published last December (subscription required to access on line): Kesselheim and colleagues performed a systematic review of studies comparing generic to brand-name cardiovascular drugs in terms of clinical outcomes, published between 1984 and 2008. They also did a content analysis of editorials in medical journals on this topic, published during the same interval.

The overwhelming results of the 47 studies they reviewed were that generic and brand-name drugs performed the same. This was true both in drugs overall and also for drugs that are thought to be especially sensitive to small dosage and absorption differences ("narrow therapeutic index").

So, if you were to believe the studies, all is well, at least in cardiovascular drug land. You can save your money and buy the cheap generic drugs. Also, indirectly, we have some reassurance that the FDA's system of requiring bioequivalence data for generic drug approval ain't broke.

But the editorials told a very different story. Fully 53% of the 43 they reviewed expressed negative views about generic substitution, and only 28% actually encouraged use of generics.

As to why the editorial writers were so far out of step with the published trial results, Kesselheim et al. hazarded the hunch, "Another possible explanation is that the conclusions may be skewed by financial relationships of editorialists with brand-name pharmaceutical companies, which are not always disclosed." And we could here add--and what about the financial relationship between the medical journal and the brand-name drug company that fills it up with ads? If editorialists write biased and non-evidence-based screeds slamming generic drugs, somebody had to pick those guys in the first place, and somebody had to print the editorial after they wrote it.

Kesselheim AS, Misono AS, Lee JL, et al. Clinical equivalence of generic and brand-name drugs used in cardiovascular disease: a systematic review and meta-analysis. JAMA 300:2514-26, 2008.

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