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New Formulations Can Delay Generic Drug Entry, Study Finds

Posted 31 January 2019 | By Michael Mezher 

New Formulations Can Delay Generic Drug Entry, Study Finds

A new study in the Journal of Managed Care & Specialty Pharmacy finds that the introduction of new formulations of drugs often delays the introduction of generic competitors by two or more years.
The study, authored by researchers at Harvard Medical School and Brigham and Women's Hospital's Program on Regulation, Therapeutics and Law (PORTAL), tracked 17 small molecule drugs approved in 2002 over the course of 15 years to see how the introduction of new formulations of those drugs affected the timing of generic competition.
While new formulations of drugs can provide benefits to patients, in some cases new formulations are introduced toward the end of a drug's patent or exclusivity protections, a practice often referred to as product hopping.
"These new formulations can expand patient treatment options, but they may also be protected by later-expiring patents or data exclusivities, which can lead to later generic entry for the new formulations compared with the original product," the authors write.
For instance, the authors cite new formulations of United Therapeutics' pulmonary arterial hypertension drug treprostinil that introduced oral and inhaled versions as an example of a product where the subsequent formulations provided tangible benefits to patients.
But for other products the benefit of new formulations is less clear. The authors point to Abbott's cholesterol drug Tricor (fenofibrate), writing, "facing loss of exclusivity on its 67mg, 134mg and 200mg capsule versions … Abbott introduced 54mg, 160mg and 200mg tablet formulations of the drug in 2001. These new formulations 'had no demonstrated incremental benefit on surrogate or patient outcomes' but generated more than $9 million in sales for the company over the next 8 years."
Of the 17 reference drugs the authors looked at for the study, nine were followed up with a total of 21 new formulations, including new dosage forms (3), strengths (5), co-formulations (5) or a combination of two or more modifications (8).
Most of the new formulations (11) were introduced within the five-year exclusivity period for the original version of the drug, though one-third (7) of the new formulations were introduced ten or more years later.
On average, the authors found that generics were launched 12.2 years after the reference products' original approval. However, generic competitors to the new formulations tended to launch later than the generic versions of the original reference product.
"The average market exclusivity garnered by new formulation products beyond the time of generic entry for their respective reference products overall (including those that garnered no additional time) was 1.2 years," the authors write.
But not all of the products with new formulations led to later generic launches. For three of the drugs, atomoxetine, ezetimibe and olmesartan, the generic versions of the original and new formulations launched around the same time.
"The patterns we found indicate that a considerable subset of these drugs were developed into new formulations with the prospect of patient benefit, as well as prolonged consumption of costly brand-name products," the authors write.
The authors also say that reproducing the study for other drug cohorts could help lawmakers "reexamine these practices and install guardrails to ensure that sufficient incentives exist for reasonable formulation innovation, as well as timely entry of low-cost generics."


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