Dr Therese Alting, Clinical Neuropsychologist at Concord and Westmead Hospitals, and board member of Huntington’s NSW ACT gives an easy to read update below.
2021 has been a tough year, and for the HD community, it wasn’t just COVID-19. So many people around the world had their hopes pinned on the ground-breaking Huntingtin-lowering drug trials that were underway. In March, the first bombshell dropped, with Roche saying that they were suspending dosing on their drug, followed quickly by a similar announcement from WAVE Life Sciences.
This was obviously disheartening. But our HD community has a history of resilience and hope in the face of this challenging disease, and there are silver linings and new green shoots in Huntington’s research. In this research update you will read a summary of where we’ve been and where we’re going.
While there are drugs available to help particular symptoms of HD, like tetrabenazine for the movements, in this review we’ll focus on treatments which aim to change the course of the disease.
In the early 20th century, as soon as Huntington’s was recognised as a disease, doctors attempted to treat its symptoms with the few tools they had available. These mostly included sedatives, but many other substances were tried out.
In the early 21st century, the next phase of research focused on a range of different drugs, which so far have not proved effective. A substance called creatine was tested in CREST-HD, but this trial stopped in 2014 as it didn’t show benefits. Pridopidine has been tested in several studies, including PRIDE-HD. Another study of this drug is now underway (PROOF-HD) in the US and Europe.
In the last decade, scientists have learned so much more about genes and how they work – this has opened up new approaches to treat diseases. The first of these interventions have focussed on lowering the amount of the damaging Huntingtin protein. We all have the “Huntington’s gene” – it produces Huntingtin in all of us. Normal Huntingtin (known as wild type HTT) is an important protein which has many roles, including helping the development of our nerve cells. Huntington’s symptoms come when a damaged version of the gene (mHTT, known as mutant or variant HTT) produces a version of the protein that starts to cause trouble in the brains of those who have inherited the gene from their parent.
Roche, Tominersen and GENERATION-HD1
In 2013, Ionis pharmaceuticals, in collaboration with the large pharmaceutical company Roche, conducted an initial trial of a new kind of therapy, which was a type of Antisense Oligonucleotide, or ASO. This trial concluded that the drug successfully lowered the production of both wild type and variant HTT. After this success, Roche became more heavily involved, relabelling the drug Tominersen.
In 2019 it launched Generation-HD, a Phase 3 study which aimed to find out whether the drug not only lowered mHTT but also slowed progression of the disease. 899 brave and generous people from around the world, including many Australians, signed up for this study. In drug trials a special independent committee reviews the results, and in March 2021, this committee advised Roche to announce that the trial was to be stopped.
Roche has provided some information about why – the main reason is that the drug didn’t slow progression of the disease. HDBuzz have provided a good summary here.
WAVE, WVE-001 and WVE002 and PRECISION-HD
The team at WAVE Life Sciences took a different approach to Huntingtin-lowering. Instead of targeting the production of wild-type and variant HTT, WAVE’s technology aimed to lower only the problem version of the gene, variant HTT. This means that the normal version of the gene would function normally. This approach, however, means that each version of the drug requires a person to have a particular variation in a DNA sequence, called a Single Nucleotide Polymorphism (SNP). To get into a trial, a participant needs to have the right SNP for that particular drug.
Unfortunately, 2 weeks after the Roche announcement, WAVE stopped its trial as it hadn’t achieved its goals of lowering the variant HTT.
Despite these setbacks, research into effective treatments has not stalled. There is a website based in the US, where you can look up drug trials being conducted – ClinicalTrials.gov: Home.
There are several studies underway overseas – the following is a summary of 2 of them.
The team at WAVE Life Sciences has not given up on its approach, and in early September, it launched SELECT-HD, or WVE-003, using a new SNP. 36 people around the world are being recruited into this study, which will test the safety of the drug. There are currently sites in Melbourne, Perth, Germany, Poland and the UK. As in the previous trials, this technology aims to lower the amount of mHTT (variant Huntingtin), while preserving the normal Huntingtin protein.
In the USA, a different kind of treatment is being tested which delivers a drug (currently called AMT-130) directly into the brains of study participants with early Huntington’s disease. In August, the company announced that 14 participants had been involved with the trial, with 8 receiving the study drug and 6 receiving placebo surgery. More detailed information can be found here.
The company hopes to complete the study by the middle of 2022.
In addition to drug trials, there are ongoing “observational studies”. These are the kind of studies that enable us to learn more about the basics of the disease so that we can then design drug treatments.
The biggest of the many observational studies is Enroll-HD, which began recruiting in 2012. The first participant at Westmead was seen in 2015. This study involves yearly visits to a clinic where a person has a neurological examination, thinking tests, answers some questionnaires and provides a blood sample. Westmead Hospital will recommence Enroll once hospital policies allow this in line with developments with COVID-19.
Enroll-HD in numbers:
|>25,000||Total number of people recruited|
|157||Number of study sites around the world|
|>750||Research papers produced in last 8 years mentioning Enroll-HD|
KEEPING UP TO DATE
The research team at Westmead Hospital is not currently recruiting for any clinical trials. As has been its practice in the past, it will inform the community of any research trials in collaboration with Huntington’s NSW ACT. The service is committed to being involved in future research, and many projects are underway overseas.
In a recent podcast, found here, Dr Ed Wild, co-founder of HDBuzz said that “we now have around a dozen Huntingtin-lowering drug trials expected to start in the next couple of years”. Despite the disappointments of the previous Roche and WAVE trials, scientists, doctors, research staff and Huntington’s family members are continuing to collaborate in the search for treatments that will make a real difference. Watch this space for future updates.
To keep up with HD research more broadly, here are 3 good websites
- HDBuzz – https://en.hdbuzz.net/
- Huntington’s Disease News – https://huntingtonsdiseasenews.com/
- HDSA Research blog – https://hdsa.org/blog/
There are also some helpful and interesting podcasts
- Help4hd – https://www.help4hd.org/podcast
- HDinsights – https://huntingtonstudygroup.org/hd-insights-podcast/
We welcome feedback and questions about HD Research. For any research enquiries, please contact the Westmead research nurses on 0456 740 612. For any Enroll-HD enquiries visit the Enroll-HD website.