Binding kinetics of darunavir to human immunodeficiency virus type 1 protease explain the potent antiviral activity and high genetic barrier.
The high incidence of cross-resistance between human immunodeficiency virus type 1 (HIV-1) protease inhibitors (PIs) limits their sequential use. This necessitates the development of PIs with a high genetic barrier and a broad spectrum of activity against PI-resistant HIV, such as tipranavir and darunavir (TMC114). We performed a surface plasmon resonance-based kinetic study to investigate the impact of PI resistance-associated mutations on the protease binding of five PIs used clinically: amprenavir, atazanavir, darunavir, lopinavir, and tipranavir. With wild-type protease, the binding affinity of darunavir was more than 100-fold higher than with the other PIs, due to a very slow dissociation rate. Consequently, the dissociative half-life of darunavir was much higher (>240 h) than that of the other PIs, including darunavir's structural analogue amprenavir. The influence of protease mutations on the binding kinetics was tested with five multidrug-resistant (MDR) proteases derived from clinical isolates harboring 10 to 14 PI resistance-associated mutations with a decreased susceptibility to various PIs. In general, all PIs bound to the MDR proteases with lower binding affinities, caused mainly by a faster dissociation rate. For amprenavir, atazanavir, lopinavir, and tipranavir, the decrease in affinity with MDR proteases resulted in reduced antiviral activity. For darunavir, however, a nearly 1,000-fold decrease in binding affinity did not translate into a weaker antiviral activity; a further decrease in affinity was required for the reduced antiviral effect. These observations provide a mechanistic explanation for darunavir's potent antiviral activity and high genetic barrier to the development of resistance.
Dierynck
Inge
I
Tibotec BVBA, Mechelen, Belgium. idierinc@tibbe.jnj.com
De Wit
Mieke
M
Gustin
Emmanuel
E
Keuleers
Inge
I
Vandersmissen
Johan
J
Hallenberger
Sabine
S
Hertogs
Kurt
K
D000595:Amino Acid Sequence; D000069454:Darunavir; D024921:Drug Resistance, Multiple, Viral; D024882:Drug Resistance, Viral; D016333:HIV Protease / Q000235:genetics* / Q000378:metabolism*; D017320:HIV Protease Inhibitors / Q000378:metabolism* / Q000494:pharmacology; D015497:HIV-1 / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics; D006801:Humans; D007700:Kinetics; D008826:Microbial Sensitivity Tests / Q000379:methods; D008969:Molecular Sequence Data; D009154:Mutation; D013449:Sulfonamides / Q000378:metabolism* / Q000494:pharmacology
D017320:HIV Protease Inhibitors; D013449:Sulfonamides; D016333:HIV Protease; D000069454:Darunavir