Videx (Didanosine, ddI) Less Effective at Once-a-Day Dosing?

The recently suggested dose of Videx at 400mg, once a day (QD) has been called into question by new data. In prior studies, the 400mg QD dose was shown to have the same virologic suppression rates as the traditional 200mg twice-a-day dosing, at least up to 24 weeks. More recent results from study AI454-148, however, showed poorer virologic suppression at 48 weeks in subjects on a regimen of once-daily Videx, Zerit (d4T), and Viracept (nelfinavir) compared with subjects on a regimen of Epivir (3TC), Retrovir (AZT), and Viracept. The proportions of subjects with HIV RNA viral loads below 400 copies were 50% and 59%, respectively, while the proportions of subjects with HIV RNA viral loads below 50 copies were 34% and 47%, respectively. There are other studies being done to directly compare the once-daily versus the twice-daily dosing, but for now, the current recommended dosing of Videx is twice daily, because there is more evidence to support the effectiveness of this dosing regimen. According to Bristol-Myers Squibb, makers of Videx, once-daily dosing should be considered only for adult subjects whose management requires once-daily dosing of Videx.