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Therapeutic substitution could significantly decrease prescription drug costs

Researchers estimated that an extra $73 billion was spent on brand-name drugs between 2010 and 2012, according to findings published in JAMA Internal Medicine.

Michael E. Johansen, MD, MS, of Ohio State University, Columbus, and Caroline Richardson, MD, of the University of Michigan, Ann Arbor, said that therapeutic substitution could help lower that cost discrepancy.

“The prescription drug market became notably more efficient after numerous states passed laws that allowed for generic substitution,” they wrote. “A similar but more controversial way to improve the efficiency of the pharmaceutical market is therapeutic substitution, which consists of substituting chemically different compounds within the same class for one another. Most physician organizations are opposed to therapeutic substitution and see it as an attack on physician autonomy. In addition, there are concerns regarding efficacy, adverse effects, drug interactions, and different indications for drugs within a class."

Johansen and Richardson conducted a cross-sectional study of 107,132 participants in the Medical Expenditure Panel Survey and their reported prescription medication use to estimate overall and out-of-pocket expenditures.

The researchers included 26 drug classes that contained both a generic or accessible over-the-counter drug and a brand-name drug without an available chemically equivalent generic in a given year.

Results showed that 62.1% (95% CI, 61.4-62.8) of participants reported using prescribed medicine between 2010 and 2012 and 31.5% (95% CI, 30.7-32.2) used medication from an included drug class. In addition, 16.6% (95% CI, 16-17.1) of participants used a brand-name drug, compared with 24% (95% CI, 23.4-24.7) of participants who used a generic and 9.1% (95% CI, 8.7-9.4) who used both.

The total expenditure for brand-name drugs was $147 billion (95% CI, 137-156), compared with $62.7 billion (95% CI, 58.9-66.5) for generic drugs. Johansen and Richardson estimated $73 billion (95% CI, 67.6-78.5) in total excess expenditure and $24.6 billion (95% CI, 22.6-26.5) in out-of-pocket excess expenditure between 2010 and 2012 was directly attributable to the overuse of brand-name drugs. That excess is equivalent to 9.6% of total and 14.1% of out-of-pocket prescription medicine expenses.

Although excess expenditure was prevalent throughout the market, the researchers identified areas of concentration on several drug classes, including proton pump inhibitors, statins, selective serotonin reuptake inhibitors, serotonin-norepinephrine reuptake inhibitors, atypical antipsychotics and angiotensin receptor blockers.

"There was a large amount of excess expenditure on branded drugs between 2010 and 2012 in classes that could have incorporated therapeutic substitution," Johansen and Richardson concluded. "Although therapeutic substitution is controversial, it offers a potential mechanism to decrease drug costs in a way that does not negatively affect quality of care."

The researchers recommended that, if the practice were to become commonplace, systems would have to allow for efficient communication between insurance companies, prescribers and pharmacies. – by Chelsea Frajerman Pardes

Disclosures: The researchers report no relevant financial disclosures.