HIV AIDS News [International Conference on AIDS (12th: 1998: Geneva, Switzerland)]

efavirenz Penetrates HIV Sanctuaries
In addition to its outstanding and durable potency, efavirenz -- like
CRIXIVAN -- has been shown to cross the blood-brain barrier and penetrate the
cerebrospinal fluid (CSF), a sanctuary where HIV hides and reproduces. This is
important, because many antiretroviral therapies are incapable of such
penetration, enabling HIV to continue to replicate within the CNS. Studies have
shown that efavirenz not only penetrates into the CSF, but achieves
concentrations which may suppress HIV replication.
Researchers presented data showing that six HIV-infected patients taking
efavirenz in dual and triple combinations had undetectable levels of viral load in
plasma and CSF (<400 copies/ml) at the recent 8th Annual Neuroscience of HIV
Infection, Basic Research and Clinical Frontiers meeting sponsored by
Northwestern Medical School. CSF drug levels and viral load were measured in
those patients who took efavirenz in combination with either CRIXIVAN, or with
AZT and 3TC, for a mean duration of 26 weeks.
"These early results demonstrating the ability of efavirenz to penetrate the
CSF are exciting," said Dr. Isaacs. "They suggest that in CRIXIVAN + efavirenz
there is a formidable combination antiretroviral treatment."
CRIXIVAN + efavirenz -- Preventing Resistance
Another major obstacle for HIV/AIDS therapy has been the ability of the
virus to mutate and produce strains that are resistant to the drugs being used to
treat it. If the virus is allowed to replicate in the presence of a drug, it will
become resistant to that drug and eventually treatment will fail. Some
antiretroviral drugs have a low barrier to resistance, requiring only one or two
mutations of the virus to prevent the drug from working effectively.
Because of its high potency, the combination of efavirenz + CRIXIVAN
suppresses viral replication very effectively, thereby restricting viral mutations.