Four-year
Analysis of Tenofovir/Didanosine Combination Therapy Effects on Lymphocytes, CD4
and Viral Load Prior
studies and reports have suggested an increased risk of pancreatitis in patients
with declining immunologic and virological parameters using tenofovir
(Viread) [TDF] in combination with didanosine
(ddI; Videx). The
current study, presented in Toronto at AIDS 2006, is and ongoing prospective analysis
of an original cohort of 72 HIV patients from 2 clinics who have been receiving
TDF 300 mg in combination with ddI-EC 250 mg once daily. CD4%, CD4 number, absolute
lymphocyte count, PCR, and amylase and lipase were assessed. Results 
72 patients were evaluated having a mean age of 47yr, 72% males, 51% non-Caucasian,
15% HCV+, 10y HIV+, 46% AIDS;
88% were ARV-experienced (mean 7.4yr HAART) prior to TDF, and 67% were on boosted-PIs
(11% LPV/r) with TDF.
Median baseline values: CD4% 21.0, CD4# 393, lymphs 1847 cells/mm3, PCR 2456c/ml
After
a median 43 months on TDF, the median change (% change) from baseline was: CD4%
+3.5% (+17.6%), CD4# +56cells (+13.2%), lymphs +111cells (+6.0%), PCR -1.1 log
(-91.3%).
64% had CD4 cell increases (51.4% ?50 cells, 45.8% >100 cells), while
23.6% (n=17) had decreases of >100 CD4 cells and ?25% absolute lymphocyte
counts.
Factors associated with lymphocyte declines include higher baseline lymphs and
PCR, lower BL CD4%, male gender, longer duration HIV+, more prior years on HAART,
and greater # prior ARV.
90.3% achieved PCR <400c/ml, 83% sustained; 79% achieved PCR <50c/ml, 68%
sustained.
AE included hypophosphatemia >GR2 (6.9%), pancreatitis (4.2%), Fanconi-like
syndrome (4.2%), and Grade 2 peripheral neuropathy (1.4%).
6 pts (8%) discontinued TDF/ddI for pancreatitis (n=3), STI (n=2), and neuropathy
(n=1).
No patients permanently discontinued TDF for renal impairment.
Based
on these results, the authors conclude, "TDF/ddI 300/250 mg once-daily in
this highly-experienced population was generally safe and efficacious with potent
and durable viral suppression. Although lymphocytes and CD4 cells increased modestly
overall, decreases were observed in a subset of patients. No patients permanently
discontinued TDF for renal impairment." 08/18/06 Reference
P Greiger-Zanlungo, G Blick, D Dupree, and others. Tenofovir DF
can be used safely in combination with didanosine-EC 250mg: a four-year analysis
of effects on lymphocytes, CD4, and viral load. 16th International AIDS Conference.
August 13-18, 2006. Abstract CDB0507.
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