Besifovir on par with tenofovir for hepatitis B virus, but safer
Besifovir dipivoxil maleate (BSV) for hepatitis B virus (HBV) infection produces lasting effects and is as good as tenofovir disoproxil fumarate (TDF), according to the results of a phase III trial. However, BSV has a better safety profile with respect to bone and renal outcomes.
The noninferiority trial randomized 197 patients with chronic HBV infection to groups given BSV 150 mg (n=99) or TDF 300 mg (n=98) for 48 weeks. Researchers analysed virologic responses to therapy (HBV DNA <69 IU/mL or 400 copies/ml), bone mineral density (BMD) and renal outcomes.
Main efficacy outcome was the proportion of patients with a virologic response at week 48. After 48 weeks, TDF was switched to BSV 150 mg for another 48 weeks.
Virologic response occurred in 80.9 percent of patients on BSV and in 84.9 percent on TDF at week 48, indicating the noninferiority of BSV to TDF. At week 96, 87.2 percent of patients in the BSV–BSV arm and 85.7 percent in the TDF–BSV arm achieved virologic response.
At week 48, significant between-group differences were noted in hip and spine BMD, in favour of BSV. However, estimated glomerular filtration rate was significantly lower in the TDF group. At 96 weeks, BMD and estimated glomerular filtration rate were comparable between the BSV-BSV and TDF-BSV arms.
The present data suggest that BSV may improve bone and kidney safety in HBV treatment, researchers said.
A relatively new oral acyclic nucleotide phosphonate, besifovir is rapidly absorbed when taken orally. Escalating doses of besifovir produce linear increase of the plasma concentration, with >60 mg doses effective for inhibiting HBV in humans. It is generally safe in terms of renal and bone toxicity, with the most common adverse event being carnitine depletion.