While HAART remains the main course of any treatment menu for CMC, experimental approaches may be useful on the side or even alone. Some block toxins pumped out by HIV-infected immune cells that likely cause neuron death; others protect the neurons from the damage done by those poisons.
- Memantine, a drug approved in Germany to treat Parkinson’s disease and dementia in the elderly, is thought to work by blocking the neurotoxin quinolinic acid. A federal trial for people with CMC is nearing completion.
- Lexipasant, an experimental drug believed to block another neurotoxin, platelet activating factor, showed a trend toward cognitive improvements in a small study of people with CMC. A larger trial by DevCo begins soon.
- CPI-1189 has been shown to counter tumor necrosis factor (TNF), a chemical secreted by activated immune cells that can injure neurons. A federal trial of this drug for CMC was recently concluded, and results are due soon.
- Antioxidants are believed to protect neurons from injury by reducing levels of cell-damaging “free radicals,” which are produced by the immune system’s anti-HIV response and implicated in similar conditions such as Alzheimer’s. Selegiline (a.k.a deprenyl), approved for Parkinson’s, has demonstrated improvements in CMC symptoms in two small studies; a larger federal trial of the patch version is now enrolling. Gingko biloba, an herbal extract, has proved effective in rolling back symptoms of early-stage Alzheimer’s dementia. Some practitioners have reported benefits for their patients with CMC.
- Peptide T, the first computer-designed antiretroviral and the first HIV fusion inhibitor, has been shown to prevent neuron death by blocking gp120, a potent HIV toxin; the drug also reduces TNF. Results of a federal trial published in 1998 showed that HIVers with CMC who took Peptide T for six months had “overall cognitive improvement,” while “overall deterioration was more common among the placebo group.” But a widely publicized 1995 federal press release based on incomplete results of the same study claimed “there was no evidence that Peptide T had an effect.”
- Nimodipine (Nimotop), a calcium-channel blocker approved for treating cerebral hemorrhages, was thought to counteract the toxic effects of gp120, but has proved disappointing as a CMC treatment.