The N155H is one of the major resistance pathway to the first-generation INI, and is often associated with secondary resistance mutations. In the study of Anstett et al., L74M, E92Q, T97A, E157Q and G163R resistance mutations were introduced into NL4.3 subtype B HIV-1 vectors harboring N155H and R263K in tandem . They found that the addition of T97A, E157Q or G163R mutation somewhat improved the affinity of the double-mutant N155H-R263K for its target DNA substrate, while the presence of L74M or E92Q had a negative effect on this step. This work showed that the compensatory mutations, that evolve after N155H selection under continued DTG or RAL/EVG pressure, are unable to improve enzyme efficiency, resistance level or viral infectivity in an N155H-R263K background .