@entity5197 (RAL) resistance is associated with the selection of integrase mutations at positions 92, 143, 148, and/or 155. A substantial proportion of RAL failures, however, occurs in the absence of these changes. An examination of RAL plasma concentrations may help in interpreting this observation. All early RAL virological failures seen at 22 clinics in Spain during 2009 were identified. @entity645 integrase sequences and RAL plasma trough concentrations (C(t)) were examined. A total of 106 @entity1 experiencing virological failure on RAL were identified. Only the earliest sample on failure was examined. Integrase sequences could be obtained for 89 (84%), of whom 30 (33.7%) depicted primary RAL resistance mutations (15 @entity23511 , eight @entity25425 /R, three @entity23512 , one @entity70312 , and three more than one of them). Another nine (10.1%) @entity1 showed only secondary changes. The remaining 50 @entity177 (56.2%) did not select any integrase change. RAL C(t) could be measured in 66 @entity1 at failure and in 21 of them before failure. In a control group of 37 @entity1 with viral suppression on RAL, detectable plasma levels were seen in all cases, with greater median RAL C(t) than in failures, either at the time of viral rebound (p<0.001) or before it (p=0.055). Moreover, median C(t) at the time of failure was greater in @entity1 selecting primary RAL resistance mutations than in the rest of the failures (p<0.001). Undetectable RAL C(t) was seen only in @entity1 failing RAL without integrase resistance mutations (64.1% of them). RAL failures in the absence of integrase resistance mutations mainly reflect poor drug compliance.

Plasma XXXX exposure influences the antiviral activity and selection of resistance mutations.

@entity1 :: ('9606', 'Species') :: ['patients'] @entity70312 :: ('p|SUB|E|92|Q', 'ProteinMutation') :: ['E92Q'] @entity645 :: ('57667', 'Species') :: ['HIV'] @entity177 :: ('MESH:D051437', 'Disease') :: ['RAL early failures'] @entity25425 :: ('p|SUB|Q|148|H', 'ProteinMutation') :: ['Q148H'] @entity23511 :: ('p|SUB|N|155|H', 'ProteinMutation') :: ['N155H'] @entity5197 :: ('MESH:C507898', 'Chemical') :: ['Raltegravir'] @entity23512 :: ('p|SUB|Y|143|R', 'ProteinMutation') :: ['Y143R']
@entity5197 :: (MESH:C507898,Chemical) :: ['raltegravir']
