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, a practice often referred to as "product hopping".

A new study via @amcporg finds that the introduction of new formulations of drugs often delays the introduction of generic competitors by two or more years.

Researchers 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. Of the 17 reference drugs in the study, nine were followed up with a total of 21 new formulations before 2007, including new dosage forms (3), strengths (5), co-formulations (5) or a combination of two or more modifications (8). Generic entry was observed in 6 of 9 cases and occurred more than 2 years later for the new formulations in 3 of the cases.
 
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.