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Good HBV Response to Tenofovir After Lamivudine Failure
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5th European HIV Drug Resistance Workshop
Cascais, Portugal
March 30, 2007
Mark Mascolini
HBV infection in 15 people coinfected with HIV responded to tenofovir after virologic failure of lamivudine (3TC) in a study reported by clinicians from the Infectious and Tropical Disease Institute in Brescia, Italy [1]. One person responded to tenofovir plus emtricitabine (FTC) and entecavir after failure of 3TC, then entecavir, and emergence of three mutations.
The study involved 40 HBV/HIV-coinfected people taking 3TC for the first time as part of an antiretroviral regimen. Twenty-five of them maintained undetectable HBV DNA for a median 1245 days (interquartile range [IQR] 34 to 2649 days) after starting 3TC. Twenty-three of these 25 added tenofovir to 3TC, while 2 switched from 3TC to tenofovir. All 25 continued to respond with an undetectable HBV DNA for a median follow-up of 72 weeks (range 3 to 234 weeks).
In the other 15 people 3TC failed to control HBV replication. Thirteen of these 15 added tenofovir to 3TC, while the other 2 replaced 3TC with tenofovir. Twelve of the 15 had HBV genotype D and 3 had genotype A. All 15 now have an undetectable HBV load after a median follow-up of 120 weeks (range 18 to 216 weeks).
HBV genotyping revealed the 180M + 204V/I mutations in most of the 15 patients with virologic failure on 3TC, although 3 had the triple mutant 173V + 180M + 204V, which may permit HBV to escape vaccination. One entecavir-naive person infected with HBV subtype D had the 233V mutation, which confers resistance to entecavir. This person regained control of HBV when tenofovir replaced lamivudine. One person responded to tenofovir plus emtricitabine and entecavir after failure of lamivudine, then entecavir, and emergence of a triple HBV resistance mutation.
Although combination therapy should be the standard of care for HBV, the Brescia team concluded, treatment sequencing with tenofovir added to or following 3TC worked in their population after 3TC failure.
Reference
1. Quiros-Roldan E, Calabresi A, Lapadula G, et al. HBV resistance-response relationship in HIV patients under tenofovir containing treatment after failure to lamivudine. 5th European HIV Drug Resistance Workshop. March 28-30, 2007. Cascais, Portugal. Abstract 85.
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