The following abstract was in the recent (February) Retroviral conference. I believe there are others:
Abstract 419 / Session 54
Viral Load and CD4+ T Cell Changes in Patients Failing Potent Protease Inhibitor Therapy.
DEEKS S*, . BEATTY G., COHEN PT, GRANT R, VOLBERDING P., UCSF AIDS Program, SF CA; Gladstone Institute of Virology, SF CA.
Objective: To describe CD4 and viral load (VL) changes in patients who fail potent protease inhibitor (PI) therapy.
Patients: 79 patients with evidence of virologic failure to potent PI therapy were identified through a retrospective cohort study. For all patients analyzed, nucleoside analogues were not modified when PI therapy was initiated. Virologic failure was defined as the 2 most recent VL assays > 500 (bDNA), both measured after seek 20 of therapy. Analysis was performed based on the CD4 and VL at the last visit (median time on potent PI therapy 14.2 months).
Results: Despite a median duration of 8.9 months since developing evidence of virologic failure, the median CD4 T cell count remained 103 cells/mm2 above the pre-PI baseline. In 58 patients with an evaluable baseline VL, 9 had no evidence of virologic response to PI therapy (defined as < 0.5 log decrease at each visit), 26 had a potent but transient response (defined as > 1 1og decrease at nadir with return to within 0.5 log of baseline) and 15 had a durable response (defined as a persistent 1 log decrease in VL below baseline). Median duration on PI therapy in this latter group was 10.9 months. For the 37 patients who achieved undetectable levels of viral RNA (<500), the median time to first detectable VL was 7 mo (range 2.4-16.5 mo).
Conclusion: Despite ongoing viral replication for > 6 months, CD4 T cells remained elevated in most patients failing potent PI therapy. A significant proportion of patients have a durable virologic response to PI therapy, despite evidence of continued viral replication. Genotypic analysis is currently being performed on a subset of patients. |
