Fostemsavir + Tenofovir Disoproxil Fumarate = Unknown or no reaction

Effect on Concentration

Fostemsavir
No change
Applies within class?
No
Tenofovir Disoproxil Fumarate
Increase
Applies within class?
No

Pharmacologic Effects

Fostemsavir
Effect
N/A
Applies within class?
No
Tenofovir Disoproxil Fumarate
Effect
N/A
Applies within class?
No

Interaction History

N/A

Last Updated 22-Nov-2022

Summary

There was no clinically relevant drug interactions found between fostemsavir and TDF in healthy subjects. The investigators concluded that no dose adjustment for either drug is necessary when co-administering two drugs.

Sources

Tenofovir disoproxil fumarate vs fostemsavir ^

Study Design

18 healthy subjects received fostemsavir (BMS-663068) 600 mg twice daily (BID) on Days 1-5, followed by tenofovir disoproxil fumarate (TDF) 300 mg once daily (QD) on Days 6-12. Subjects then administered fostemsavir 600 mg BID concomitantly with TDF 300 mg QD on Days 13-19. Serial blood samples were collected on Day 5 and 19. Samples for fostemsavir were collected pre-dose and up to 24 hours post-dose on Days 5 and 19; Samples for TDF were collected on Days 12 and 19.

Study Results

When patients were given fostemsavir (600 mg BID) together with TDF (300 mg QD) for 19 days, TDF had no significant effect on fostemsavir PK parameters. The geometric mean ratios (GMRs; fostemsavir + TDF / fostemsavir) [90% CIs] of fostemsavir were: 0.986 [0.861, 1.130] for Cmax and 1.004 [0.910, 1.107] for AUC.Coadministration with fostemsavir (600 mg BID) resulted in modestly increased pharmacokinetic (PK) parameters of TDF. GMRs (fostemsavir + TDF / TDF) [90% CIs] of TDF were: 1.18 [1.12, 1.25] for Cmax and 1.19 [1.12, 1.25] for AUC. The investigators considered these changes are not clinically significant since similar or greater magnitude of increase in tenofovir exposure was observed in coadministration of TDF and ritonavir-boosted protease inhibitor with no effects on safety or tolerability.

Study Conclusions

References

L Zhu, C Hwang, V Shah, et al. No clinically significant drug interaction when bms-663068, a novel hiv-1 attachment inhibitor, is coadministered with tenofovir disoproxil fumarate. abstract p_13. 13th International Workshop On Clinical Pharmacology Of Hiv Therapy. Barcelona, Spain. ; 2012.