Drug resistance acquired in rare cases of HIV infection during treatment with pre-exposure prophylaxis (PrEP) quickly disappears after drug discontinuation, the researchers report on Aids. Use of ultra-sensitive tests six months after seroconversion and abandonment of PrEP in failure, did not find any remaining resistant copies.
Studies have shown that the risk of PrEP resistance development is very low, but it is a major concern for anyone starting PrEP during acute infection unrecognized, comment the authors. "Our data show that resistance in these selected cases decays rapidly to levels below the highly sensitive detection of these assays."
PrEP with tenofovir and emtricitabine (Truvada) Or tenofovir (Viread) Alone is highly effective in preventing infection with HIV. However, resistance to these antiretrovirals have been detected in individuals who started PrEP not recognized during acute HIV infection, and very rarely in HIV-infected patients receiving Prep.
Such resistance may limit future treatment options for HIV. So it is important to determine whether it is important or necessary to persist after cessation of treatment. To answer this question, researchers of the study Partnes about PrEP designed a longitudinal study involving nine patients with anti-HIV drug resistance (with K65R mutations, K70E and / or M18IV) detected during seroconversion. The stored blood samples were tested to see if it was transmitted or acquired resistance because of Prep. Ultra-sensitive assays were used to monitor resistant strains of the virus six, twelve and 24 months after the cessation of PrEP.
Blood samples that were filed with RNA of HIV-positive people, antibody-negative were available prior to seroconversion to four of the nine patients. None of these patients showed resistance mutations before seroconversion, suggesting that the resistance was acquired pre-exposure prophylaxis treatment because instead of being transmitted.
PrEP was stopped immediately after detection of seroconversion. Ultrasensitive assays were used to see if the resistance persisted after pre-exposure prophylaxis be removed.
The resistant virus levels were reduced - or fallen - to below the limit of detection in all patients six months after treatment was discontinued and remained undetectable 24 twelve-month follow-up after.
"Resistance related to PrEP PrEP drops rapidly after cessation," the researchers comment. "For six months after seroconversion (after PrEP was discontinued), resistance mutations K65R, K70E and / or M184IV who were present at seroconversion were no longer detected, even with highly sensitive resistance testing."
Only one patient started antiretroviral therapy (ART) within 40 months after seroconversion. This patient initiated treatment in 33 months, with a combination of nevirapine / emtricitabine and tenofovir. Viral load was approximately 19.000 copies / ml. Three months after the start of ART this patient had an undetectable viral load.
Researchers were called for future studies to examine whether PrEP associated with resistance affects subsequent treatment response.
Translated by Claudio Souza's original During acquired drug resistance HIV PrEP rapidly disappears after medication is discontinued.
Reviewed by Mara macedo
Written po Michael Carter
Published: December 14 2015