A Cohort Study of the Food Effect on Virological Failure and Treatment Discontinuation in Patients on HAART Containing Didanosine Enteric-Coated Capsules (FOODDIe Study)

BACKGROUND: Didanosine enteric-coated capsules (ddI-EC) should be taken under fasting conditions. However, the effect of food on the absorption of ddI-EC may not reduce exposure to the drug. METHOD: We performed an observational study to assess the effect on virological failure of taking ddI-EC with food. To be included, patients had to have begun their first ddI-EC-containing HAART regimen between June 1, 2001 and June 1, 2003. Primary endpoints were virological failure or discontinuation of the ddI-EC-containing regimen. RESULTS: 668 patients were included (119 patients were naïve, 172 switched from a different regimen, and 377 were part of rescue therapy). 296 patients were taking ddI-EC with food. After 71 weeks of follow-up, 162 discontinued ddI-EC in the fasting group and 120 in the fed group. 46 patients had virological failure (19 without food vs. 27 in the group with food). Adherence to therapy >80% was 79.7%. We fitted a multivariate Cox proportional hazard model and found a significant interaction between ddI-EC intake and adherence. The multivariate model showed that when adherence to HAART was poor (<80% of prescribed pills) taking ddI-EC with food significantly increased the risk of virological failure (hazard ratio [HR] 8.32, 95% CI 1.67-41.65), but this disappeared when adherence was 80%-95% (HR 0.27, 95% CI 0.04-1.53) or >95% (HR 0.57, 95% CI 0.12-2.77). CONCLUSION: When adherence is good (>80% of the prescribed doses), ddI-EC can be administered with food without an increase in virological failure or HAART discontinuation.