What is 'resistance' or 'drug resistance'?
The appearance of resistance makes the HIV virus less sensitive to the antiviral activity of one
or more drugs. In the presence of an ineffective antiretroviral therapy, taken irregularly and/or at suboptimal doses, the viral
genome tends to change by replacing one or more aminoacids. These mutations lead to the synthesis of "mutated" viral enzymes, less
sensitive or resistant to the action of antiretroviral drugs directed against that particular enzyme, eg. reverse transcriptase,
protease and integrase.
What is 'multi-resistance'?
The progressive accumulation of mutations can lead to the phenomenon of multiresistance, that is
the loss of sensitivity to different classes of antiretroviral drugs. Virus-resistant carriers are defined as multi-resistant when
harbouring resistance to reverse transcriptase inhibitors, protease inhibitors and integrase inhibitors.
What are the factors that can contribute to multi-resistance?
There are several factors that can foster the onset of multiresistance: inadequate intake of the
antiretroviral therapy; poor tolerability or toxicity of the antiretroviral regimen, which promote poor adherence; exposure to suboptimal
antiretroviral therapy; ineffective regimens as best chance due to the lack of new therapeutic options.
What are the consequences of multi-resistance?
LPeople with HIV infection harbouring a multi-resistant virus constitute a "fragile" population for
several reasons. The availability of new therapeutic options to regain complete viral suppression is very limited and the presence of
a detectable viremia is associated with a progressive reduction of CD4+ lymphocytes and a significative risk of disease progression.
There are consequences also for the community: a detectable viremia, in fact, increases the risk of transmitting to another person a
multi-resistant virus, more difficult to treat.
How can multi-resistant patients be treated?
The construction of an effective therapy against a multi-resistant virus often requires the use
of combinations of antiretroviral drugs with adjusted doses. Currently it is also possible to benefit from some innovative drugs
inside clinical trials. For these reasons, careful and regular monitoring by Infectious Diseases specialists, together with an adequate
team of Virologists and Pharmacologists, is strongly recommended.