Background: Telithromycin (Ketek) was approved in April 2004 for the treatment of acute bacterial exacerbations of chronic bronchitis (ABECB), bacterial sinusitis, and community-acquired pneumonia. The approval of telithromycin was controversial due to trial irregularities, noninferiority study designs, and use of foreign safety data. Safety concerns involving hepatotoxicity, myasthenia gravis exacerbation, and visual disturbances were increasingly documented in the literature after approval. On February 12, 2007, the U.S. Food and Drug Administration (FDA) removed the bacterial sinusitis and ABECB indications and strengthened safety warnings for telithromycin.
Objective: To (1) assess the prevalence and distribution of on-label telithromycin utilization before and after the revisions of the product label and (2) assess the association of pivotal events in the life cycle of telithromycin with its use as reflected in pharmacy and medical claims.
Methods: Using retrospective administrative medical and pharmacy claims from a large midwestern commercial insurer with an eligible membership of 1.8 million members, individuals with a telithromycin claim during January 1, 2007, through April 13, 2007, were identified. Their medical claims within 30 days prior to or on the initial telithromycin claim were analyzed for the presence of an on-label diagnosis code. Monthly telithromycin and clarithromycin claim totals per million members from January 2004 through March 2007 were calculated. Claim totals were plotted to identify utilization trends in relation to the FDA health advisory for telithromycin on January 20, 2006, and the telithromycin label changes on February 12, 2007.
Results: The medical diagnosis analysis consisted of 507 members with 1 or more medical claims with dates of service within 30 days of at least 1 pharmacy claim for telithromycin. Using the original approved telithromycin indications, 52.3% (256 of 507) of telithromycin use was on-label. The most common on-label diagnoses were sinusitis (33.9%) and bronchitis (14.4%). A diagnosis of pneumonia was present for 3.9% of telithromycin utilizers. After the February 12, 2007, label change limiting telithromycin to community-acquired pneumonia, on-label use was 6.7% (12 of 179) of utilizers. Telithromycin claims were first detected in August 2004 and overtook the clarithromycin rate of 729 claims per million members in January 2005, reaching a peak rate of 940 claims per million members in January 2006. Telithromycin monthly claims remained higher than clarithromycin until April 2006, 3 months after the liver toxicity health advisory. In comparison with January 2006, the January 2007 telithromycin claims were 186 claims per million members, a decrease of 80%.
Conclusion: Despite revised FDA indications and safety warnings, fewer than 1 in 15 active telithromycin users have a medical claim consistent with the only currently approved indication (pneumonia). Pharmacy claims for telithromycin dropped substantially following reports of severe hepatotoxicity and strengthened safety warnings. The high prevalence of telithromycin off-label use despite hepatotoxicity and other safety risks is cause for continued concern.