Baraclude improves renal function in HBV after stopping Viread

BOSTON — Entecavir monotherapy is an effective rescue strategy for improving renal function in patients with hepatitis B virus infection after switching from therapy with Viread, according to findings presented at The Liver Meeting.

“Recently, tenofovir alafenamide showed better renal safety profile compared to tenofovir disoproxil fumarate. … We wanted to assess whether entecavir may be a safe and effective rescue strategy for chronic HBV patients developing kidney dysfunction during long-term tenofovir disoproxil fumarate treatment,” Mauro Viganò, MD, PhD, of the Ospedale San Giuseppe, University of Milan, Italy, said during his presentation in an HBV parallel session.

Viganò and colleagues evaluated 103 patients with chronic HBV consecutively switched from Viread (tenofovir disoproxil fumarate, Gilead Sciences; TDF) therapy, after developing renal toxicity after 35 months of monotherapy, to Baraclude (entecavir, Bristol-Myers Squibb). Of these, 40% had reduced doses of TDF during treatment.

Every 4 months the researchers measured serum creatinine, estimated glomerular filtration rate (eGFR) by MDRD, phosphate, fraction of phosphate re-absorption, dipstick urine analysis, alanine aminotransferase and virologic response by sensitive PCR assay.

At the initiation of entecavir therapy, 91% of patients had a eGFR less than 90 ml/minute; 72% had phosphate levels below 2.5 mg/dl; and 50% had fraction of phosphate re-absorption less than 0.80 mmol/L. Three-percent of patients had TDF-induced Fanconi syndrome and 3% of additional patients had proteinuria at urine analysis.

Over the course of 27 months of entecavir treatment, all parameters of renal function improved: creatinine improved from 1.26 to 1.11 mg/dL (P < .0001); eGFR from 54 to 65 mL/minute (P = .003); phosphate from 2.2 to 2.6 mg/dL (P < .0001); and fraction of phosphate re-absorption from 0.47 to 0.62 mmol/L (P < .0001).

Among patients who experienced reduced eGFR, hypophosphatemia and hyperphosphaturia, the researchers observed improvement of at least one parameter in 35%, 80% and 73% of cases. Normal values were achieved by 5%, 10% and 39% of patients, according to Viganò’s presentation.

The two patients with TDF-induced Fanconi syndrome completely normalized renal function after 16 and 24 months of entecavir therapy.

None of the patients experienced entecavir-related adverse events, Viganò said during his presentation.

“A TDF-to-entecavir switch improves glomerular an tubular function in most patients developing kidney dysfunction while on long-term TDF treatment,” Viganò said. “However, renal function fully recovered in 38% of the patients, only.” – by Melinda Stevens

Reference:

Viganò M, et al. Abstract 70. Presented at: The Liver Meeting; Nov. 11-15, 2016; Boston.

Disclosures: The researchers report no relevant financial disclosures.