Is There a Cure for Huntington's Disease in Trials?

While there is currently no cure for Huntington’s disease (HD), the landscape of research has dramatically shifted. Instead of only developing medications to manage symptoms—like involuntary movements or mood changes—scientists are now actively testing disease-modifying therapies in human clinical trials. These treatments aim to slow, stop, or even prevent the progression of the disease by targeting its root cause.

The core problem in Huntington’s disease is a genetic “stutter” that causes the body to produce a toxic, abnormally long, and misfolded protein called mutant huntingtin (mHTT). This misshapen protein clumps together, building up and damaging delicate brain cells over time. Because this protein is the primary driver of the damage, researchers believe that reducing its levels could halt the disease. This strategy is known as HTT-lowering (or huntingtin-lowering) ^[1].

HTT-Lowering Therapies in Clinical Trials

Scientists are testing several different methods to lower the amount of mutant huntingtin protein in the brain ^[2]. These mid-stage clinical trials are testing approaches that differ in how they work, how they are delivered to the patient, and their specific risk profiles.

• Antisense Oligonucleotides (ASOs): ASOs are synthetic strands of DNA or RNA designed to bind to the genetic instructions for the huntingtin protein, signaling the cell to destroy them before the protein is made. Because they cannot cross the blood-brain barrier effectively, ASOs are typically delivered via regular spinal taps (intrathecal injections) ^[3]. While a major trial for a drug called tominersen was halted in 2021 due to safety and efficacy concerns, researchers learned from the data and are now testing it in a younger, earlier-stage population ^[3]. Other ASOs in development aim to be “allele-selective,” meaning they only target the toxic mutant protein while leaving the healthy, normal huntingtin protein intact ^[4].
• Gene Therapy (RNA interference): Gene therapy aims to provide a long-lasting or permanent solution. For example, AMT-130 is an investigational gene therapy that uses a harmless virus to deliver instructions directly into the brain, telling cells to produce a molecule that continuously blocks the huntingtin protein ^[3]. This requires a one-time neurosurgical procedure. Early phase 1/2 trial data suggests it has been generally well-tolerated, with researchers closely monitoring patients for long-term safety and potential clinical benefits ^[3].
• Small-Molecule Splicing Modulators: These are oral medications (pills) designed to alter how the huntingtin genetic instructions are processed, ultimately reducing the amount of protein produced ^[1][5]. Being able to take a pill rather than undergo spinal taps or brain surgery is a major advantage. Drugs like PTC518 are currently in mid-stage clinical trials, demonstrating the ability to lower huntingtin levels in the blood and cerebrospinal fluid ^[3].

Measuring Success and Managing Risk

Because these trials are investigating whether a drug can slow down a slowly progressing disease, researchers use biomarkers to measure success. A key biomarker is neurofilament light chain (NfL), a protein released when brain cells are damaged ^[6]. By measuring NfL and mutant huntingtin levels in the blood or spinal fluid, scientists can gauge whether a drug is successfully protecting the brain, even before clinical symptoms change ^[7].

It is important to understand that these trials carry significant risks, which vary by the type of treatment. For example, gene therapy requires invasive neurosurgery, which carries structural risks to the brain, while certain past oral splicing modulators (like branaplam) caused nerve damage in the hands and feet ^[3]. Some trials have been paused or stopped because the drugs did not work as hoped or caused unexpected side effects like brain swelling ^[3][8]. However, even trials that stop early provide vital information that guides the next generation of treatments.

Who Can Join These Trials?

A common and urgent question is whether people who carry the HD gene mutation but do not yet have symptoms (pre-manifest) can join these trials. Currently, most active drug trials require patients to be in the early manifest stage, meaning they have begun to show clear physical or cognitive symptoms.

However, the field is actively working toward prevention. As drugs are proven safe in early-manifest patients, researchers plan to test them in pre-manifest individuals to see if the disease can be delayed or prevented entirely. While these cutting-edge therapies are still years away from standard FDA approval, the sheer number and variety of root-cause treatments in human trials offer unprecedented hope ^[9][10].

If you want to get involved today, consider observational trials like Enroll-HD, which tracks patients across all stages of the disease (including pre-manifest) to help researchers understand HD and design better trials. You can find active studies near you using resources like the Huntington’s Disease Society of America (HDSA) HD TrialFinder or clinicaltrials.gov.