The Huntington's disease (HD) research field is entering 2025 with a sense of optimism, fueled by promising clinical trial results and regulatory advancements. Key opinion leader Professor Ed Wild shared his hopeful outlook, highlighting potential breakthroughs and ongoing challenges in the development of effective treatments for HD.
uniQure's Gene Therapy Shows Promise
uniQure's gene therapy trial has generated excitement due to its innovative approach and encouraging early data. The therapy involves a surgically injected, genetically engineered virus that reprograms neurons to produce a drug that lowers huntingtin protein production. According to Prof. Wild, two-year data from the trial indicate that treated patients are doing significantly better than controls, with a notable reduction in disease progression, especially in functional scores. "The combination of clinical signals moving in the right direction and NfL below baseline is what I’ve been looking for for the past 20 years, and never seen until last year in the uniQure data update," Wild stated.
Furthermore, uniQure announced productive discussions with the FDA, resulting in the agency's endorsement of neurofilament light (NfL) as a valuable biomarker and composite UHDRS (cUHDRS) as a clinical endpoint. The cUHDRS, which combines Total Functional Capacity (TFC), Total Motor Score (TMS), Symbol Digit Modalities Test (SDMT), and Stroop Word Reading (SWR), is particularly useful because it captures the diversity of HD symptoms and reduces the number of participants needed for clinical trials by approximately 40%.
PTC Therapeutics' Votoplam and Other Clinical Trials
PTC Therapeutics is also expected to release full results from its huntingtin-lowering drug, votoplam, in early summer. The drug, administered as a pill, has shown a clean safety signal in early trials. Alynlam Pharmaceuticals has also initiated a huntingtin-lowering trial, with initial results expected towards the end of the year. Roche's tominersen, after facing negative results in 2021, is undergoing another trial targeting younger patients with smaller CAG repeats and lower doses. Results are anticipated in mid-2026, with a possible interim analysis sooner.
Biomarker Research and CAG Expansion
Significant research efforts are focused on identifying and validating biomarkers for HD. Prof. Wild emphasized the need for an imaging marker to visualize huntingtin protein in the brain, similar to PET scans used in Alzheimer's disease for amyloid and Tau proteins. He also highlighted the importance of developing markers for CAG expansion, which could aid in the development of treatments targeting DNA repair proteins like MSH3. "Biomarkers for the process of CAG expansion would be huge for HD," Wild noted.
Challenges and Future Directions
Despite the optimism, challenges remain in translating scientific progress into tangible benefits for HD patients. Access to healthcare and the high cost of innovative therapies, such as gene therapies, pose significant barriers. Prof. Wild stressed the importance of addressing these challenges to ensure that scientific advancements improve the lives of those affected by HD. He also advised the HD community to remain informed and proactive in their healthcare decisions, emphasizing that "hope is good, and to squander hope, or to let hope go unused or unfulfilled is a tragedy."
