Valopicitabine (NM283) 200mg/day demonstrated comparable antiviral activity to the results obtained in the 800mg/day-containing arms in a preliminary analysis of an ongoing phase IIb clinical trial in treatment-naive genotype 1 patients at 12 weeks of treatment.
To date in this clinical trial, the 200mg/day dose has also demonstrated improved tolerability compared to the 800mg/day dose.
“More than 70% of patients receiving this regimen achieved viral clearance at week 12 utilizing the Amplicor assay’s lower limit of quantification of 600 copies/mL, which is substantially higher than we generally see in clinical practice in HCV genotype 1 patients,” noted Dr Douglas Dieterich, professor of medicine at the Mt Sinai School of Medicine, New York and an investigator in the study.
In the 200mg/day arm, 87% of patients achieved an early virologic response (EVR), defined as greater than or equal to 2 log10 (100-fold) reduction in virus after 12 weeks of treatment, compared to 88% in the pooled 800mg/day arms.
At 12 and 16 weeks, 71% and 73%, respectively, of patients in the 200mg/day arm reached undetectable virus levels below 600 copies/mL compared to 73% and 74% in the pooled 800mg/day arms.
After 12 and 16 weeks, 45% and 62%, respectively, of patients in the 200mg/day arm reached undetectable virus levels below 20 copies/mL, compared to 56% and 61% in the pooled 800mg/day arms.
In addition, through 12 weeks of treatment, in the ongoing phase IIb clinical trial, discontinuations in the 200mg/day arm occurred at a rate significantly less than the higher dosing regimens, at 6% and 22%, respectively. Through week 12, a total of 24 patients discontinued for adverse events, with two occurring in the 200mg/day arm.
Idenix is developing valopicitabine, and other hepatitis drug candidates, in collaboration with Novartis Pharma.