This paper analyses generic-to-branded drug switch-back patterns in the statin class.Methods
Utilizing LifeLink™ Anonymized Patient Level Data (APLD) from IMS Health, 17.3 million unique treated patients over a 2-year period from July 2006 to June 2008 were analysed. Switch-backs to branded drugs were analysed for patients who started on a branded drug and were switched to a generic statin, or for patients who started therapy on a generic drug.Key findings
A total of 538 000 patients, or 3.1% of the total number of treated patients, engaged in switch-backs, of which 69 000 and 469 000 patients are bioequivalent and therapeutic switch-backs, respectively. Excluding 9.7 million patients never on generic drugs, 7.1% of the remaining 7.6 million patients engaged in switch-backs. Switch-back patterns increased with greater patient health risk such as increasing age and co-morbidities. Higher patient doses of simvastatin increased switch-back rates, from about 10% at the 5 and 10 mg doses to 16% at the 80 mg dose. Among switch-back patients, 37% had high cardiovascular risk based on the number of co-morbidities. Switch-backs increased with physician specialty status.Conclusions
Managed care controls play a significant role in encouraging initial brand-to-generic substitution which in turn results in switch-back patterns for some classes of patients. Future research considerations and policy implications are discussed. The results suggest that while generic drugs seem to be as good as branded drugs most of the time, this may not always be true. Thus, a universal policy approach mandating generic utilization for all patients, particularly when driven on purely cost grounds, is not appropriate.