April 5, 2011
In March 2011, the FDA approved a new formulation of the NNRTI Viramune (nevirapine). Viramune XR is a new 400mg, once-a-day extended release tablet, which hopefully will improve adherence for many people. This FDA approval is based upon results from the prospective 48-week VERxVE study (1,048 people) and a 24-week study called TRANxITION (443 people).
Anyone new to therapy who starts Viramune must scale up the drug to avoid serious allergic reactions, regardless of their desire for this new once-a-day dosing or the old twice-a-day dose. For the first two weeks, everyone should start 200mg of Viramune just once a day.
On day 15, the dose is increased to 400mg per day, more than likely as one 400mg XR pill once a day or as one 200mg pill taken twice a day. However, if a rash is present during the 14-day lead-in, Viramune XR should not be started on day 15. The lead-in dose should not be continued beyond 28 days, at which point another regimen should be decided.
Anyone already taking a 200mg Viramune pill twice a day can safely switch the new extended release pill.
Viramune or Viramune XR should not be started in women with CD4s above 250 or in men with CD4s above 400, unless the benefits outweigh the risks — though the patient should be carefully monitored for allergic reactions.
The VERxVE study showed nearly the same side effects from the new extended release tablet, with liver problems in about 6% of the people on Viramune XR vs. 9% on the twice-a-day pill. Severe or life-threatening rash occurred in 1% of those on either regimen. A total of 80% on Viramune XR had undetectable viral loads compared to 75% on the twice-a-day dose. CD4s increased an average of 206 cells on XR and 191 cells on the twice-a-day dose.
Comparable results on undetectable viral loads and CD4 increases were also seen in the TRANxITION study.