1 Adherence to ARV Therapy and Resistance HAIVN Havard Medical School AIDS Initiative in Vietnam.
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Transcript of 1 Adherence to ARV Therapy and Resistance HAIVN Havard Medical School AIDS Initiative in Vietnam.
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Adherence to ARV Therapy and Resistance
HAIVNHavard Medical School AIDS
Initiative in Vietnam
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By the end of this session, participants will be able to:Present the importance of good adherence to ARV therapyList the 5 main reasons leading to non adherenceDescribe 3 types of adherenceExplain the relationship between adherence and drug resistance
Learning Objectives
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Adherence
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Adherence means taking right drugs, in proper dose and on time
To achieve the best effect with ARV therapy, adherence rate is required to be above 95%• Example: If medications are prescribed
2 times a day, don’t forget more than 2 doses a month.
Definition
Common types of adherence
Howard AIDS 2002; Ickovics Antiviral Ther 2002; Moss CID 2004
Adh
eren
ce
Treatment time (month)
100%
0%0 12 24
Three types of patient’s adherence
Very good adherenceReduced adherenceNon adherence
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Any activity:support, or help to improve the health of people with HIV / AIDSpay attention to the care and treatment of people with HIV, including:
• Physical health status• Mental, psychosocial well-being
Extended definition of adherence
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Maximal inhibition of viral load Reduce drug resistance Ensure effect time of drug All above helps:
• Slow progression of HIV• Prolong survival
Goals of adherence to ARV drugs
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Drug resistance
Adherence: Definition
Adherence : according to Kaufman and Le Moing, WHO
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Patients who do not improve on• clinical• immunologic and • viral outcome
after starting ART therapy are considered not to respond to treatment
Non adherence: Definition
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Resistance leads to the failure of ARV therapy
Intolerance with ARV drugs aggravates the disease
Drug interactions causes ARV levels below the threshold of viral suppression
Non adherence: Causes
Drug resistance
Drug resistance is often, but not always due to non adherence
How does HIV drug resistance occur?
Resistant virus
Social/ personal issuesRegimen issue
ToxicityPoor quality drugs
Wrong doseHost genetics
Poor absorption
Rapid clearance
Poor activation
Drug interaction Transmission
Poor adherence
Insufficient drug level
Viral replication in the presence of drug
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HIV has an extremely high rate of replication
The new generation of virus is little different from the previous generation
Some structural changes can improve the ability of viral replication• When virus can multiply in the presence
of ARV drugs, it can be said that virus is resistant to drugs
How does HIV develop resistance?
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Level of drugs below the threshold of treatment
Wild-type virus
Resistant virus
Effect of non adherence to the development of viral mutations
The relationship between the level of adherence and the risk of drug
resistance
Williams & Fiedland, 1997
Ris
k of
dru
g re
sist
ance
% Adherence0 100
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Some comments: 50% of people living with HIV (not taking into account the current status of treatment) there is evidence for at least one drug resistance78% of people who have HIV treatment are resistant to at least one antiviral drug
Resistant HIV
CROSS-RESISTANCE: Resistance to a drug in a group often leads to resistance to another drug in that group!
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Drug resistant HIV can transmit: to new HIV infectionsas well as to co-infections
Risk of transmission
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ARV therapy failure is often, but not always, due to drug resistance
Failure of ARV therapy is expressed by:• Increased viral load• Reduced CD4 count + T cells• Progression to AIDS
ARV therapy failure
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Good adherence will reduce the risk of the development of ARV resistance
Drug resistance is a major problem• For individuals • For society
Why is adherence mentioned?
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Good adherence to ARV therapy is necessary but very difficult
Non adherence results in low drug concentration in the blood and allows the development of drug resistant HIV
ARV resistance leads to treatment failure
Transmission of drug-resistant virus from one person to another occurs and is a public health problem
Key points
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Thank youQuestion?