Evidence of 3TC resistance after treatment interruptions

Anna Poppa
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This article is more than 23 years old.

Scottsdale, Arizona: According to two research groups, supervised treatment interruptions (STIs) in people taking 3TC-containing regimens, can result in the emergence of 3TC resistance. These data were presented at the Fifth Resistance Workshop in Arizona today.

The first study, from Bruce Walker’s lab at Massachusetts General Hospital and Havard Medical School, found the 3TC signature mutation M184V emerged during periods off therapy in one of fourteen people undergoing STIs after beginning anti-HIV therapy in acute infection. M184V was not detected in this person prior to treatment, nor when sequenced at day 3 of the first STI, but had emerged by day 21 (Tremblay).

A team from Badalona, Spain, similarly detected the 3TC mutation in two of twelve people participating in a study of STIs in chronically infected patients. M184V emerged at the end of the second and third STIs (Morales-Lopetegi).

Glossary

acute infection

The very first few weeks of infection, until the body has created antibodies against the infection. During acute HIV infection, HIV is highly infectious because the virus is multiplying at a very rapid rate. The symptoms of acute HIV infection can include fever, rash, chills, headache, fatigue, nausea, diarrhoea, sore throat, night sweats, appetite loss, mouth ulcers, swollen lymph nodes, muscle and joint aches – all of them symptoms of an acute inflammation (immune reaction).

half-life

The amount of time it takes for a concentration in blood to be reduced by 50%. After one half-life, the concentration of a drug in the body amounts to half the starting dose of any drug to be eliminated from the body.

Both groups hypothesise that 3TC’s long half-life may have been the cause of the problem. After stopping treatment, the drug remains at tapering levels in the blood for some time. These low levels create the right climate for selection of 3TC resistance mutations.

References

Tremblay C et al. HIV evolution during repeated supervised treatment interruptions following early antiretroviral treatment of acute infection. Antiviral Therapy 2001; 6(Supplement 1):17.

Morales-Lopetegi K et al. Selection of M184V mutation during repetitive cycles of structured antiretroviral treatment interruptions. Antiviral Therapy 2001; 6(Supplement 1):28.

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