The arrival of multiple generic copies last year proved a zero-sum gain for their branded counterparts, as prescribing for branded drugs declined 2.6% and fewer patients were started on them, a study shows.
New-patient starts with branded products decreased 17.7% from 2005 to 2006, according to an analysis from prescription data house Verispan.
Use of non-branded versions of such drugs as Merck’s cholesterol-reducer Zocor (simvastatin), as well as Pfizer’s antidepressant Zoloft (sertraline) and its antibiotic Zithromax (azithromycin), spiked after key patents on the drugs expired. Generically dispensed prescriptions increased 11.4% overall compared to 2005, according to the study, called Verispan Vector One: National.
Data provided to MM&M show that as of April of this year, new prescriptions written for generic simvastatin had increased nearly six-fold, as sales for the cheaper copies topped $1.8 billion in the 10 months since their arrival last June. Meanwhile, Zocor new scripts fell 87% during the period.
Moreover, in the six months following the introduction of generic simvastatin, patient compliance with the non-branded cholesterol reducer was nearly 3% better than compliance among those taking branded statins, Verispan said. The compliance metric is derived from measuring the time between start and refill dates.
Other events driving higher generic use included the Medicare prescription drug benefit, which launched in 2006 and brought greater price transparency on brand-name drugs. By the end of Medicare Part D’s first year, the proportion of total generics used by Part D patients had increased to 60%, a 5% rise over the beginning of the year, Verispan noted.
Generics continued to take the lion's share of Rx in the first two months of 2007, as total generic prescriptions were up 11.9% as compared to the same period last year while total branded Rx declined 2.6%. New scripts for branded products declined 4.3% during the period.