
Going boldly: First person treated in Phase 1 clinical trial by Alnylam Pharmaceuticals
A new Phase 1 clinical trial for the huntingtin-lowering drug ALN-HTT02 was initiated this week with the first dose given. Read on to learn details about the trial and how it compares to other ongoing huntingtin-lowering trials in the clinic.

On December 3, 2024 a study site gave word that the very first person received a new drug, called ALN-HTT02, as part of a Phase 1 trial aiming to treat Huntingtonâs disease (HD). Going boldly as the first human ever to receive this drug, theyâre charting a course that we all hope will one day lead to a disease-modifying drug for HD. Letâs dig into the details of this new trial!
Who is behind this new trial?
In September, Alnylam Pharmaceuticals announced that they were launching a clinical trialclinical trial Very carefully planned experiments designed to answer specific questions about how a drug affects human beings to test their huntingtin-lowering drug. A spelling error in the gene huntingtin, called HTTHTT one abbreviation for the gene that causes Huntingtonâs disease. The same gene is also called HD and IT-15 for short, is what causes HD. Those who inherit this spelling mistake in HTTHTT one abbreviation for the gene that causes Huntingtonâs disease. The same gene is also called HD and IT-15 will go on to develop changes with mood, movement, and memory as HD progresses. Lowering levels of the HTTHTT one abbreviation for the gene that causes Huntingtonâs disease. The same gene is also called HD and IT-15 molecule with the spelling mistake is one strategy being tested in the clinic to potentially treat HD.

Image credit: HDBuzzâs own Dr. Ed Wild!
Alnylam is a relative newcomer to the scene of HD therapeuticstherapeutics treatments, but theyâre not new to drug discovery. Theyâve been around for 22 years and received commercial approval for their first drug 6 years ago. They also have experience with other brain disorders; theyâre currently advancing towards a Phase 2 trial for a drug that they hope will treat Alzheimerâs disease.
The company is named for the bright center star in the constellation Orionâs belt, âAlnilamâ. As that star has been used for thousands of years by navigators, it symbolizes Alnylamâs passion for discovery. For some, this star represents a bridge between earthly and celestial realms. Hopefully all these positive cosmic analogies are good luck and Alnylamâs drugs can bridge us to an HD-free future!
Molecular Mars Rovers
The drug that Alnylam is developing in collaboration with Regeneron Pharmaceuticals that is being tested in this trial is called ALN-HTT02. It works through a mechanism called âRNA interferenceRNA interference A type of gene silencing treatment in which specially designed RNA molecules are used to switch off a geneâ, also known as RNAiRNA interference A type of gene silencing treatment in which specially designed RNA molecules are used to switch off a gene. RNAiRNA interference A type of gene silencing treatment in which specially designed RNA molecules are used to switch off a gene is unique because it takes advantage of molecular machinery that already exists inside cells for processing â like little Mars Rovers processing samples from the red planet. RNAiRNA interference A type of gene silencing treatment in which specially designed RNA molecules are used to switch off a gene is Alnyamâs specialty. They developed the worldâs first RNAiRNA interference A type of gene silencing treatment in which specially designed RNA molecules are used to switch off a gene-based medicine! (A drug used to treat a nerve disease.)
ALN-HTT02 itself is a piece of synthetic genetic material that contains a code to recognize HTTHTT one abbreviation for the gene that causes Huntingtonâs disease. The same gene is also called HD and IT-15. Once itâs introduced into a cell, the cellâs own molecular machines are used to process the synthetic genetic material. This creates a fragment of the synthetic genetic material that binds to the HTTHTT one abbreviation for the gene that causes Huntingtonâs disease. The same gene is also called HD and IT-15 message to lower it.
ALN-HTT02 targets the first bit of the HTTHTT one abbreviation for the gene that causes Huntingtonâs disease. The same gene is also called HD and IT-15 gene called âexonExons The small fraction of our DNA that is directly used to instruct cells how to make proteins 1â. This is the part of the genetic message that contains the spelling error that causes HD. Researchers think that exonExons The small fraction of our DNA that is directly used to instruct cells how to make proteins 1 could be the key to driving toxicity that builds up over time, damaging brain cells. Hopefully by specifically targeting this area, that damage will be lessened, or stopped altogether.
âPhase 1 trials are the first time that drugs developed in the lab are ever given to humans! Knowing that theyâre safe and well tolerated by people is the first step in advancing them in the clinic.â
Same twinkle, different star
Other ongoing clinical trials are taking a similar approach â targeting HTTHTT one abbreviation for the gene that causes Huntingtonâs disease. The same gene is also called HD and IT-15 to lower levels. While there are similarities to these other trials, there are also some subtle differences.
Like most other trials, ALN-HTT02 is what we call âtotal HTTHTT one abbreviation for the gene that causes Huntingtonâs disease. The same gene is also called HD and IT-15â lowering. That means it targets both copies of the HTTHTT one abbreviation for the gene that causes Huntingtonâs disease. The same gene is also called HD and IT-15 gene, the one from mom and the other from dad. This means that both regular HTTHTT one abbreviation for the gene that causes Huntingtonâs disease. The same gene is also called HD and IT-15 and the HTTHTT one abbreviation for the gene that causes Huntingtonâs disease. The same gene is also called HD and IT-15 with the spelling mistake are lowered. Other companies, like Wave Life Sciences and Vico Therapeuticstherapeutics treatments, are running trials that specifically or preferentially target only the copy of HTTHTT one abbreviation for the gene that causes Huntingtonâs disease. The same gene is also called HD and IT-15 with the disease-causing spelling mistake.
There are currently quite a few HTTHTT one abbreviation for the gene that causes Huntingtonâs disease. The same gene is also called HD and IT-15 lowering drugs being tested in clinical trials, but the way the drugs actually lower HTTHTT one abbreviation for the gene that causes Huntingtonâs disease. The same gene is also called HD and IT-15 levels differs. Companies like Wave, Vico, and Roche are using something called an antisense oligonucleotideASOs A type of gene silencing treatment in which specially designed DNA molecules are used to switch off a gene, or an ASOASOs A type of gene silencing treatment in which specially designed DNA molecules are used to switch off a gene. This is a short piece of genetic material that binds the HTTHTT one abbreviation for the gene that causes Huntingtonâs disease. The same gene is also called HD and IT-15 message molecule to lower levels. So it doesnât use the cellâs molecular machinery to produce the message-binding fragment the way that RNAiRNA interference A type of gene silencing treatment in which specially designed RNA molecules are used to switch off a gene does.
Companies like PTC Therapeuticstherapeutics treatments and Skyhawk Therapeuticstherapeutics treatments are using something called splice modulators that target HTTHTT one abbreviation for the gene that causes Huntingtonâs disease. The same gene is also called HD and IT-15 to lower levels. These are small molecules taken as a pill that target the way the HTTHTT one abbreviation for the gene that causes Huntingtonâs disease. The same gene is also called HD and IT-15 message molecule is processed, causing it to be sent to the cellâs trash can, like the waste containment units on the International Space Station. (Clearly there are only so many relevant space analogiesâŠ)
Similar to Alnylam, uniQure is using an RNAiRNA interference A type of gene silencing treatment in which specially designed RNA molecules are used to switch off a gene-based approach. The difference between uniQure and Alnylam though is that uniQureâs drug AMT-130 is carried in a harmless virus and delivered via brain surgery. Conversely, Alnylamâs ALN-HTT02 isnât encapsulated in a virus and is delivered via spinal injection.

Overall though, all of the drugs being tested by these companies have the same goal â lower the HTTHTT one abbreviation for the gene that causes Huntingtonâs disease. The same gene is also called HD and IT-15 message to hopefully reduce the toxic effects of the protein with the goal of slowing or stopping HD.
Details about the trial
ALN-HTT02 is being tested in Phase 1 trial. As with all Phase 1 trials, the primary goal of this study will be to determine if it is safe. Phase 1 trials are the first time that drugs developed in the lab are ever given to humans! Knowing that theyâre safe and well tolerated by people is the first step in advancing them in the clinic.
Theyâll also look at how well the drug targets HTTHTT one abbreviation for the gene that causes Huntingtonâs disease. The same gene is also called HD and IT-15 and how levels change in the CSFCSF A clear fluid produced by the brain, which surrounds and supports the brain and spinal cord., the fluid that bathes the brain. Theyâll use clinical tests to measure symptoms, but would need a larger trial with different measures to understand if ALN-HTT02 works to change clinical features of HD.
Up to 54 people with Stage 2 or early Stage 3 HD between the ages of 25 and 70 are being recruited for this trial. Recruitment age is notable here, as most trials exclude those over the age of 65.
Currently, recruitment is only open at two sites in the UK, but the study is also being initiated in Canada and recruitment in additional countries is expected to follow.
âWe are profoundly grateful to these brave volunteers who help answer questions about new drugs, taking the first steps across the bridge to a future without HD.â
Participants will be given a single dose of ALN-HTT02 via spinal injection during the trial. A portion of the participants will be given a placeboplacebo A placebo is a dummy medicine containing no active ingredients. The placebo effect is a psychological effect that causes people to feel better even if theyâre taking a pill that doesnât work., an injection that contains no active drug. After 6 months, those who received the placeboplacebo A placebo is a dummy medicine containing no active ingredients. The placebo effect is a psychological effect that causes people to feel better even if theyâre taking a pill that doesnât work. will be given the option to receive an injection that contains ALN-HTT02.
Guided by the stars
As our first trial participant steps boldly into a future unknown, guided by a company that is inspired by the stars, we hope this charts a new path for HD therapeuticstherapeutics treatments. Phase 1 trial participants are incredibly brave, like astronauts walking courageously into the unknown.
We are profoundly grateful to these brave volunteers who help answer questions about new drugs, taking the first steps across the celestial bridge to a future without HD.
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