Huntington’s Disease

Many experimental treatments aim to lower the clumps of mutant huntingtin protein that build up in the brain, but doctors need a way to see whether they are working. This study tested a radioactive tracer, [18F]CHDI-385, that lights up huntingtin aggregates on PET brain scans in mice. The tracer reliably detected the clumps, suggesting a similar scan in people could one day track whether a therapy is clearing the toxic protein, which would speed the testing of disease-modifying treatments.

The involuntary movements (chorea) of Huntington's disease are commonly treated with VMAT2 inhibitors, a group of drugs that includes tetrabenazine, deutetrabenazine and valbenazine. This analysis pooled results from several randomized trials to weigh how well these medicines reduce chorea and how safe they are. Overall the drugs meaningfully lessened involuntary movements, with generally manageable side effects. The review helps patients and doctors compare current symptom-easing options while researchers keep working toward treatments that slow the disease itself.

The length of the CAG repeat in the HTT gene largely sets when Huntington's disease begins, but people with the same length can still differ widely. Studying carriers of smaller expansions, researchers found that hidden spelling variations within the repeat, missed by standard tests, strongly influence age of onset and how the disease progresses. Detecting these variants could sharpen predictions for families and improve how future trials group participants, since two people with identical repeat counts may face very different timelines.

AMT-130 is an investigational one-time gene therapy for Huntington's disease. Delivered by a harmless virus placed directly into the brain's striatum during surgery, it carries genetic instructions designed to switch down production of the mutant huntingtin protein at its source. This review summarizes how AMT-130 works and the early clinical findings that have raised hopes it could become the first treatment to slow the disease rather than only ease symptoms. It remains experimental and is still being tested in trials.

Tominersen is an experimental antisense drug, given by spinal injection, that lowers the harmful huntingtin protein. Using data from treated patients, researchers modelled how the drug's level in spinal fluid relates to how much it reduces mutant huntingtin and shifts other disease markers. Mapping this dose-to-effect relationship helps explain earlier trial results and guides the choice of dose and schedule in ongoing studies, part of the effort to find a form of huntingtin-lowering that is both safe and effective.

This expert review, from leading Huntington's researchers, draws together current understanding of why the disease strikes in adulthood. A central theme is somatic expansion, the way the CAG repeat keeps growing inside vulnerable brain cells over decades until it triggers their death. The authors explain how this insight is reshaping treatment strategy, from lowering the mutant protein to slowing the repeat expansion itself, and outline the therapies now moving toward and through clinical trials.

PROOF-HD was a large phase 3 trial testing pridopidine, an oral drug that acts on the sigma-1 receptor, in people with early Huntington's disease. Across the whole study group, pridopidine did not significantly slow decline in daily function or the combined disease-rating score versus placebo at 65 weeks, and it was generally well tolerated. Although the main goals were not met, the detailed results inform how pridopidine and similar approaches are studied next. Discuss any treatment questions with your care team.

This landmark study measured the CAG repeat one cell at a time in human Huntington's brains and found a striking pattern: in the most vulnerable neurons the repeat quietly grows from around 40 to many hundreds over years, and cells only begin to sicken once it passes about 150. This suggests much of the disease's long silent phase reflects that slow DNA expansion, strengthening the case for therapies that stop the repeat from growing as a way to delay or prevent the loss of neurons.

Beta-blockers are inexpensive, widely used heart and blood-pressure medicines that calm the body's stress signalling. Analyzing the large Enroll-HD database, researchers found that people carrying the Huntington's mutation who took beta-blockers tended to be diagnosed later and to progress more slowly than closely matched people who did not. Because this is an observational comparison rather than a controlled trial, it cannot prove the drugs caused the benefit, but it makes beta-blockers a promising, testable candidate for slowing Huntington's.

Brain cells in Huntington's disease struggle to make enough energy early on. Triheptanoin is a specially designed oil that feeds the cell's energy-producing machinery. In this phase 2 trial in France and the Netherlands, patients with early Huntington's took triheptanoin or placebo for six months, and researchers tracked shrinkage of a key brain region (the caudate) along with movement scores. The results help clarify whether boosting brain energy metabolism can affect disease measures and whether the approach is worth pursuing further.

Some earlier animal and post-mortem studies suggested that a chemical route called the kynurenine pathway is disturbed in Huntington's disease, making it a possible treatment target. To test this in living patients, researchers measured six kynurenine-pathway chemicals in the spinal fluid and blood of 141 people with HD and 75 healthy controls from the HDClarity study. They found no significant differences between the groups and no link to disease severity. This careful negative result helps redirect drug-development effort away from a pathway that does not appear to be dysregulated in people with HD.

Juvenile-onset Huntington's disease, which begins in childhood or adolescence, has been thought to involve early developmental delay, but that idea rested on retrospective chart reviews. Here, parents of children with juvenile HD and of gene-negative comparison children completed detailed birth-and-milestone questionnaires. There were no significant differences in prematurity, birth weight, birth complications, or motor and verbal milestones, even among children with very large CAG expansions. The findings suggest juvenile HD does not show up as developmental delay before movement symptoms begin, reassuring families and refining how doctors understand this severe early-onset form.

Huntington's disease damages the brain as the mutant huntingtin protein clumps inside neurons, so clearing those aggregates is a key treatment goal. This study tested an experimental small molecule, LM11A-31, which acts on a receptor called p75NTR. In lab-grown human cells and two HD mouse models, the drug switched on the cell's waste-recycling system (autophagy) and reduced huntingtin aggregates in the striatum, the brain region hit hardest in HD. By helping neurons clear the toxic protein, this approach points toward a possible disease-modifying therapy, though it remains at the preclinical stage.

The HTT gene normally carries a short stretch of CAG repeats; a large expansion causes Huntington's disease. This German study asked whether repeat lengths below the disease threshold affect mental health. Comparing thousands of people with depression or anxiety against healthy controls, it found that full HD-range mutations were not more common, but certain combinations of shorter repeat lengths on the two gene copies were linked to anxiety risk and to subtle differences in the basal ganglia brain structures, especially with age. The work hints that normal-range HTT variation may gently influence mood and brain anatomy.

Genetic counseling is required before Huntington's disease gene testing, but travel and cost put it out of reach for many. This US randomized trial compared counseling delivered by video (telegenetic) with in-person counseling; each participant experienced both. Satisfaction was uniformly high (a median 10 out of 10) with no meaningful difference between formats, and the main advantage of video counseling was saving travel time. Interestingly, most people already showing HD symptoms still preferred meeting in person. The results support video counseling as a way to widen access to HD testing.

Huntington's disease is caused by an expanded CAG repeat in the HTT gene, and researchers are racing to turn that understanding into treatments. This review surveys the pipeline of small-molecule drugs being developed for HD, explaining how each candidate is built and what it targets in the disease's biology. Only two drugs, tetrabenazine and deutetrabenazine, are currently approved (both for the involuntary movements called chorea), but several more are in clinical trials. It offers families a clear map of the experimental medicines that may reach the clinic.

Chorea, the involuntary dance-like movements of Huntington's disease, can be eased by drugs called VMAT2 inhibitors. This US study tracked how two of them, deutetrabenazine (approved for HD chorea and tardive dyskinesia) and valbenazine, spread into real-world prescribing between 2017 and 2020. Prescriptions rose steadily each year, with neurologists leading for deutetrabenazine and psychiatrists for valbenazine. Understanding how a new HD treatment reaches patients, and what influences doctors to adopt it, helps ensure that people who could benefit actually gain access to it.

What is it actually like to live with Huntington's disease? This Spanish study across 17 movement-disorder clinics asked 102 people with HD directly, using questionnaires on quality of life, life satisfaction, mood, stigma, and daily function. Most had motor symptoms, and many also faced behavioral or psychiatric difficulties; depression affected about 37% and notable hopelessness about 33%, alongside meaningful levels of stigma. Capturing patients' own experiences, including concerns about death and finding meaning, helps clinicians and families address the emotional and social burdens of HD, not just its physical signs.

Africans are underrepresented in Huntington's disease research, and it was long assumed the mutation reached the continent only through European ancestors. This study tested people with chorea and their relatives across five sub-Saharan countries for the expanded HTT gene. HD was confirmed in every country, with about half of chorea patients carrying the mutation (typically around 45 CAG repeats). By also mapping family trees, the researchers estimated how many relatives are at risk. The findings improve recognition and genetic counseling for HD in African communities long overlooked by research.

PIVOT-HD tested PTC518, now called votoplam, a tablet that changes how the huntingtin gene's message is spliced so that less of the protein is made. It is taken by mouth and crosses into the brain, avoiding the spinal injections that other huntingtin-lowering drugs require. One hundred and fifty-nine people with early Huntington's disease at 28 sites in eleven countries took one of two doses or placebo, with safety and the amount of huntingtin in blood as the main measures.

What happenedThe trial completed in 2025 and posted results in 2026: huntingtin protein in blood fell by about 17 percent on the lower dose and 29 percent on the higher dose at three months, against essentially no change on placebo (p<0.0001), and the drug was generally tolerated. That was enough for the program to move into phase 3, which is recruiting now and is listed above. It is the clearest demonstration so far that a tablet can lower huntingtin.

SELECT-HD tested WVE-003, an antisense drug given by lumbar puncture and designed to be allele-selective: to lower the mutant copy of the huntingtin gene while largely leaving the healthy copy alone, which matters because the normal protein has jobs of its own. Forty-seven people took single or repeated doses, or placebo, at 23 sites across ten countries. Safety and tolerability were the primary measures.

What happenedThe study completed in 2024 and results were posted in 2025. Treatment-related side effects were uncommon at the doses tested, which is the bar an early study like this has to clear. Its scientific interest lies in the allele-selective design: showing that a drug can distinguish between the two copies of a gene, sparing the healthy one, is a template other Huntington's programs and other dominant genetic diseases are now following.

PROOF-HD tested pridopidine, a sigma-1 receptor agonist taken as a tablet twice a day, in 499 people with early manifest Huntington's disease at 58 sites across eleven countries. Unlike huntingtin-lowering drugs it was not aimed at the protein itself but at protecting cells under stress. The main measure was Total Functional Capacity, the standard scale for whether someone can still work, manage money and look after themselves.

What happenedThe trial completed and reported in 2023 that pridopidine did not meet its primary endpoint: functional capacity declined by 1.18 points on the drug and 0.95 on placebo, a difference that was not statistically significant (p=0.17). Some pre-specified subgroups, particularly participants not taking certain other medications, looked more favorable, and the sponsor has pursued those. As a treatment for early Huntington's disease, though, this trial did not deliver.

VIBRANT-HD tested branaplam, a tablet originally developed for spinal muscular atrophy that turned out, unexpectedly, to also lower the huntingtin protein. Twenty-six people with early manifest Huntington's disease at twelve sites in five countries took the drug or placebo, with the amount of mutant huntingtin in spinal fluid as the main measure. An oral huntingtin-lowering drug would have been a major practical advance over injections into the spine.

What happenedNovartis halted the trial in 2023 after signs and symptoms suggesting peripheral neuropathy, nerve damage in the limbs, appeared in treated participants; everyone who had received the drug was then followed for up to a year. The posted results show the drug worked as intended on its target, lowering mutant huntingtin in spinal fluid by about 27 percent against roughly no change on placebo. The safety finding, not a lack of effect, ended the program.

GENERATION HD1 was the largest huntingtin-lowering trial ever run: 899 people with manifest Huntington's disease at 96 sites in eighteen countries, receiving tominersen, an antisense drug given by lumbar puncture that lowers both the mutant and the healthy forms of the huntingtin protein. It was the first real test of the central idea in Huntington's research, that reducing the toxic protein should slow the disease.

What happenedRoche stopped dosing in March 2021 on the recommendation of an independent monitoring committee. The posted results show why: on the composite disease scale, participants on the more frequent dosing schedules did worse than those on placebo, and the every-eight-weeks group fared worst of all. Later analysis suggested younger participants with less advanced disease may have benefited at lower doses, and tominersen is now being retested at lower doses in a separate trial rather than abandoned.

KINECT-HD tested valbenazine, a once-daily capsule that reduces the dopamine signalling behind involuntary movements, in 128 people with chorea due to Huntington's disease at 46 sites in the United States and Canada. Chorea is the restless, uncontrollable movement that many people find among the most socially difficult symptoms. The main measure was the Total Maximal Chorea score, which rates involuntary movement across seven parts of the body.

What happenedThe trial met its primary endpoint clearly: chorea improved by 4.6 points on valbenazine against 1.44 on placebo, a difference of 3.16 points (p<0.0001). On the strength of this result the FDA approved valbenazine for chorea associated with Huntington's disease in August 2023, making it one of the few approved treatments for any symptom of the condition. A long-term safety study for participants who continued on the drug is listed among the active trials above.

LEGATO-HD tested laquinimod, an oral drug developed for multiple sclerosis that dampens the immune response inside the central nervous system, in 352 people with Huntington's disease at 53 sites across ten countries. Three doses were compared with placebo over a year. The main measure was the motor section of the Unified Huntington's Disease Rating Scale, and brain-volume change on MRI was a key secondary measure.

What happenedThe trial completed in 2018 without meeting its primary endpoint: motor scores did not improve compared with placebo (p=0.49), and the highest dose arm had already been discontinued earlier in the study for safety reasons seen in the multiple sclerosis program. Brain-volume loss was reduced on the drug, an interesting signal that was not matched by any clinical benefit, and laquinimod was not taken further in Huntington's disease.

2CARE was a large academic trial of high-dose coenzyme Q10, a widely available supplement thought to support the energy-producing machinery of cells, in 609 people with early Huntington's disease at 49 sites in the United States, Canada and Australia. Participants took 2,400 mg a day or placebo and were followed for up to five years, making it one of the longest treatment trials in the disease.

What happenedAn interim futility analysis in July 2014 found less than a five percent chance that the trial would show a benefit, and it was stopped. The final analysis confirmed the outcome, with essentially identical results in the two groups. The finding matters beyond the drug itself: coenzyme Q10 had been widely taken by people with Huntington's disease on the strength of small earlier studies, and this trial is the reason it is no longer recommended.