What regimen would you recommend switching to in a situation involving a patient with evidence of virologic failure to her only regimen - ddI, d4T, nelfinavir - and a resistant genotype report as follows:
PPI: 46L, 71V, 30N, 88D
NRTI: 184V, 118I, 44D, 210W, 215Y, 41L?
Dr. David Katzenstein responds:
This patient has evidence of extensive nucleoside resistance, moderate PI resistance (predominantly to NFV) and likely is susceptible to NNRTIs. Considerations in the choice of a new regimen include the CD4 count, virus load and the patient's adherence and tolerance characteristics. If the goal of a new regimen is to suppress virus replication, I would recommend at this point a 3 class "salvage regimen." Based on the recent 384 results as well as the potential for lactic acidosis and neurologic toxicities, it would be best to discontinue ddI and d4T. Abacavir is not likely to be a particularly potent drug in the presence of multiple NRTI mutations.
Three-class regimen:
A boosted protease inhibitor (Kaletra, SQV+RIT, or IDV+RIT)
An NNRTI (EFV or NVP) and
Continuation of 3TC (300mg + tenofovir 300mg as qd dosing).
The simplest regimen is likely to be the most successful, and I would recommend Kaletra + EFV or NVP (see package inserts for dose adjustment in the presence of RIT) and 3TC+TDF as a single qd dose.
