In a study of mice, an experimental drug developed at the University of Virginia reversed paralysis and vision loss caused by a disease that mimics multiple sclerosis. The drug, called kamuvudine-9 or K-9, has not been tested as an MS treatment in people. The results were published in Science Translational Medicine.
The finding stands out because current MS medicines mainly aim to prevent new inflammatory attacks rather than restore function already lost. Still, many treatments that work in mice fail in human trials, and people living with MS should not change their treatment based on this research.
The Mouse Study Results
Researchers induced an MS-like disease in mice and waited until symptoms were visible before starting treatment, according to the National Institutes of Health, which funded the work. The mice then received K-9 for two weeks. Treated animals were protected from further neurologic decline and recovered from earlier movement problems and vision loss.
No other group of mice, including those given a standard approved MS drug, recovered nearly as much. The drug appeared to protect nerve fibers and their insulating myelin sheaths, which MS damages. It also halted the rise in neurofilament light chain, a blood marker of nerve damage.
K-9 is a modified version of nucleoside reverse transcriptase inhibitors, or NRTIs, a class of drugs approved for HIV and hepatitis B. Those drugs also block the inflammasome, part of the innate immune system that can trigger cell death in the brain and spinal cord. The researchers believe K-9's benefits likely came from preventing the inflammasome from activating. K-9 is described as a nontoxic derivative of NRTIs.
The team had earlier shown that K-9 protected retinal structure and function in mice with retinal detachment.
Why Mouse Results Are Only a First Step
The disease in these mice resembles MS but is not the same as the human condition. Mouse models often respond to drugs that later fail in people because of differences in biology, disease timing, and dosing. The researchers themselves emphasize that controlled clinical trials will be needed to learn whether the recovery seen in mice applies to humans.
The team also analyzed health data from more than 3 million patients and found lower rates of MS and MS relapses among people taking NRTIs. That analysis shows an association only, and NRTIs are different molecules from K-9. "Though NRTIs are different molecules, they too block inflammasome activation," lead developer Dr. Jayakrishna Ambati said in the NIH release.
Readers should also know about financial interests. Ambati is a co-founder of Inflammasome Therapeutics, the company developing K-9 and a related drug, K-8. That does not make the research wrong, but it is one reason independent replication and human trials matter.
Current Status of K-9 in Human Testing
K-9 is not new to people. It has already been tested in clinical trials for eye conditions, including diabetic macular edema and thyroid eye disease, and the related drug K-8 has shown promise for late-stage macular degeneration. Harvard researchers are also evaluating K-9 for ALS, UVA Today reported.
The authors hope to move K-9 into clinical studies for MS and other neurodegenerative diseases. No MS trial of K-9 has been announced publicly, and even if one begins soon, it would likely take years to learn whether the drug is safe and effective for people with MS.
Guidance for People Living with MS
People with MS should keep taking prescribed disease-modifying therapy and should not seek out HIV medications or unapproved compounds based on this research. Stopping an MS medication without medical guidance can raise the risk of relapse.
Those interested in future studies can ask their neurologist about clinical trials or search ClinicalTrials.gov for multiple sclerosis studies. Trial participation usually involves eligibility screening, travel and time commitments, so it helps to ask what costs are covered before enrolling.
New or worsening symptoms, such as sudden vision loss, weakness, numbness or trouble walking, should be reported to a clinician promptly because they may signal a relapse. Sudden weakness on one side or trouble speaking may be a stroke and requires a 911 call.
The UVA findings add to growing interest in the inflammasome as a treatment target. For now, a promising mouse result has earned a closer look in human trials, not a place in treatment.
Key Questions Answered
What did the UVA study find?
In mice with an MS-like disease, the experimental drug K-9 reversed paralysis and vision loss and protected nerve fibers and myelin.
Has K-9 been tested for MS in people?
No. It has been tested in people for some eye conditions, but not as an MS treatment. Human trials would be needed.
How is K-9 different from current MS drugs?
Current MS drugs mainly prevent new inflammatory attacks. K-9 targets the inflammasome and, in mice, appeared to restore lost function.
Is K-9 related to HIV drugs?
Yes. It is a modified, nontoxic derivative of a class of HIV and hepatitis B drugs called NRTIs.
Do the researchers have financial ties to the drug?
Lead developer Dr. Jayakrishna Ambati co-founded Inflammasome Therapeutics, the company developing K-9.
Should people with MS change their treatment?
No. Keep taking prescribed therapy and discuss questions about new research or clinical trials with a neurologist.
Published by Medicaldaily.com
