Alternatives to Ribavirin

Taribavirin
Ribavirin has the risk of inducing severe anaemia. If this occurs then it is likely that the dose of ribavirin will be reduced, which in turn is thought to reduce the chances of achieving SVR. Taribavirin (formerly called viramidine) is a pro-drug of ribavirin that is converted to ribavirin in the liver rather than kidney. This potentially reduces the risk of anaemia and so it is hoped that less people will be forced to reduce their dosage. Taribavirin is taken orally.

In March 2008 the company released week 12 results from the trial and so far the results are looking better in 2 of the higher dose arms (click here to read the full report) with lower rates of anaemia than in the ribavirin arm. Side effects are similar except for diarrhea which was approximately twice as common in taribavirin patients as ribavirin patients. However, the diarrhea was generally mild and not treatment limiting for taribavirin or ribavirin patients

In 2007, the company began a Phase IIb study to evaluate higher doses of taribavirin than used in the VISER trials, while also employing a weight-based dosing regimen, consistent with the dosing regimen for ribavirin.