Clinical Research

Clinical research are studies involving human volunteers (also called participants) that is intended to add to medical knowledge. The research is carried out in order to provide scientific evidence for the safety, and efficacy-the ability to produce the desired result.

There are two main types of clinical studies: interventional studies (also called clinical trials) and observational studies. Within these there are subtypes and the explanations are listed below

👉 Definition:
The researcher actively assigns an intervention (e.g., a new drug, vaccine, surgery, or behavioral program) to participants to see its effect on a specific outcome.

🧠 Key Characteristics:
-Researcher controls the exposure.
-Can establish cause-and-effect relationships.
-Usually more expensive and complex.
-Commonly used in drug and vaccine trials.

📊 Types:
-Randomized Controlled Trials (RCTs) – gold standard for testing efficacy.
-Non-randomized interventional studies – intervention is given but not randomly assigned.

Definition:
An interventional therapeutic is a drug, biologic, device, procedure, or other medical intervention that is intended to produce a clinical benefit by treating, curing, or preventing disease.

Purpose:
-To evaluate efficacy and safety of a therapy.
-To directly improve patient outcomes.

Examples:
-Administering a monoclonal antibody to neutralize TNF-α in rheumatoid arthritis.
-Using insulin to treat diabetes.
-Performing a stent placement to open a blocked artery.

Key point:
-The target is the illness or problem in the body, and the therapy is the treatment used to help the patient get better.

 

Definition:
An interventional biomarker is a measurable biological characteristic (e.g., protein level, gene expression, imaging finding) that is actively modified or targeted in a clinical study to understand its role in disease or therapy, but is not itself the direct therapy.

Purpose:
-To see if changing a body signal or measurement actually helps improve the disease
-To confirm whether the biomarker is truly linked to causing the disease or can be used as an early sign that treatment is working
-To help doctors choose the best treatment for different patients based on their test results or condition

Examples:
-Lowering LDL cholesterol with a drug to test whether LDL reduction (the biomarker) causally improves cardiovascular outcomes.
-Modulating amyloid-β plaques in Alzheimer’s disease to test if plaque reduction impacts cognitive decline.
-Increasing hemoglobin F (fetal hemoglobin) in sickle cell disease to see if it reduces crises.

Key point:
-The treatment is aimed at changing a biological marker in the body, but that marker itself is not the actual medicine or treatment.

👉 Definition:
The researcher does not assign any treatment. Instead, they observe and collect data on what happens naturally or in routine care.

🧠 Key Characteristics:
-No randomization or active intervention.
-Researcher only observes existing exposures or behaviors.
-Cannot prove cause-and-effect as strongly as interventional studies (more prone to bias and confounding).
-Usually easier, cheaper, and faster to conduct.
-Useful for studying risk factors, long-term outcomes, or rare side effects.

 

Main focus:
-Any exposure or health outcome

-Researchers observe people without giving treatment

Example:
Studying whether smoking is linked to heart disease

 

Main focus:
-Biomarkers (body signals/measurements)

-Researchers observe how biomarkers relate to disease or treatment response

Example:
-Checking whether a blood protein predicts cancer progression

 

Main focus:
-How a disease changes over time naturally

-Researchers track the course of a disease without experimental intervention

Example:
-Following patients with Parkinson’s disease for years to see how symptoms progress

 

How are the trials and studies done?

Everyone who wants to conduct a trial or study needs approval from the authoroties and ethic committees.  Drug trials performed in Europe needs approval both from the European Medicines Agency and from the ethic committees in each country where there are participants.  These authorities are responsible for vetting the risk/benefit ratio of the trial – their approval does not mean that the therapy is ‘safe’ or effective, only that the trial may be conducted.

Depending on product type and development stage, investigators initially enroll volunteers or patients into small pilot studies and subsequently conduct progressively larger scale comparative studies. Clinical trials can vary in size and cost, and they can involve a single research center or multiple centers, in one country or in multiple countries. Clinical study design aims to ensure the data collected in the study holds high standards and measure the potential effect – positive, negative or no effect – in a scientifically sound way.  The procedures has to be publicly available to allow independent evaluation of the reported results.

FROM LABORATORY TO APPROVED TREATMENT

Click below to learn more about how medicines are approved by the European Medicine Agency (EMA)

CLINICAL TRIALS EXPLAINED BY Hoffmann-La Roche

Learn about the stages and types of clinical trials. Find also the frequently asked questions (FAQ) about Huntington’s studies.

WHY SHOULD I GET INVOLVED?

Scientists work constantly to find enhanced ways to treat diseases, but improved treatments can never become a reality without testing in clinical trials with human volunteers. Individuals with HD are urgently needed to participate in the ongoing enrolling clinical trials focused on HD. In some studies, those who are at risk, caregivers and healthy volunteers are also needed. Recruiting and retaining trial participants is now the greatest obstacle, other than funding, to developing the next generation of HD’s treatments.

By participating in clinical research, you can help to accelerate progress and provide valuable insight into potential treatments and methods of prevention.

Benefits of clinical trials
Participating in clinical trials has the potential to help both the individual participant and other individuals who have HD or are at risk of developing it:

  • You can play a more active role in your own health care.
  • You can gain access to potential treatments before they are widely available.
  • You can receive expert medical care at leading healthcare facilities — often free of cost — while participating in important medical research.
  • You can help future generations by contributing to HD research.

Risks of participation
Patient safety is the most important aspect of every HD clinical trial. The procedures for each study are reviewed by an expert committee not directly involved in the trial, helping ensure that patient safety is protected.

There are risks, however, when participating in clinical trials:

  • There may be unpleasant or even serious side effects related to the potential treatment(s) being studied.
  • The experimental treatment may not be effective.

Details of risks related to participation in the clinical study are spelled out in the consent form participants (or their proxies) sign when they agree to participate.

Reasons for optimism
No new treatment advances to the clinical testing phase unless there is strong evidence indicating it will be as effective as, or more effective than, currently available therapies. Every clinical trial contributes valuable knowledge, whether or not the treatment works as hoped.

Participating in clinical studies gives us optimism for today and promise for the future. They provide many participants with access to cutting-edge treatments and expert medical care. And some day they will lead us to the end of HD.

Participants receive a high standard of care
All participants receive regular care related to the trial and opportunities to talk to clinical trial staff. Research shows that people living with the disease who are involved in clinical trials tend to do somewhat better than people in a similar stage of their disease who are not enrolled in clinical trials, regardless of whether the experimental treatment works. Scientists believe this advantage may be due to the general high quality of care provided during clinical trials.

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siRNA

A way of silencing genes using specially designed molecules of RNA – like DNA but made of only a single strand – that target the message molecules in cells and tell them not to make a certain protein

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phenoptype

Phenotype refers to an individual’s observable traits, such as height, eye color and blood type. A person’s phenotype is determined by both their genomic makeup (genotype) and environmental factors.

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oxidative seres

an imbalance between unstable molecules called “free radicals” and protective “antioxidants” in your body

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Metabolism & bioenergetics

describe how your body turns food into fuel and uses that energy to live. 

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Small Molecule

a tiny chemical compound, much smaller than big biological structures like proteins, that can easily travel inside our cells to act as medicine (like aspirin or ibuprofen), a building block (like glucose), or a signaling tool in the body, often taken as pills because they’re easy to absorb and distribute

 

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Nucleic acid

(DNA and RNA) are the essential information-carrying molecules in all life, acting like blueprints that store and transmit genetic instructions for building and operating cells, directing everything from growth to protein production, and passing traits from parents to offspring.

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SNP-single nucleotide polymorphisms

a single-letter spelling difference in a gene. SNPs, pronounced ‘snips’, are common and most don’t change the function of the gene.

 
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at risk

You do not know if you carry the genetic mutation for HD gene 

 
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TFC-total functional capacity

A standardized rating scale for function in HD, used to assess capacity to work, handle finances, perform domestic chores and self-care tasks.
Scores range from 0 to 13, with higher scores indicating better functional capacity. 

 
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Double-blinded

 means that neither the participant nor the clinical trial doctor can choose or know the group the participant is in until the trial is over. This approach helps to prevent bias.

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Open label

A trial in which the patient and doctor know what drug is being used. Open label trials are susceptible to bias through placebo effects.

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Gene therapy

a technique that aims to treat or prevent diseases by modifying a person’s genes. It involves introducing, removing, or changing genetic material (DNA or RNA) within a patient’s cells.

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UHDRS- Unified Huntington Disease Rating Scale

A standardized neurological examination that aims to provide a uniform assessment of the clinical features of HD

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CAG repeat

The stretch of DNA at the beginning of the HD gene, which contains the sequence CAG repeated many times, and is abnormally long in people who will develop HD

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Wild-type

the opposite of ‘mutant’. Wild-type huntingtin, for example, is the ‘normal’, ‘healthy’ protein

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Tolerabilty

How well a person can handle a treatment without having serious or uncomfortable side effects.

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Striatum

Part of the brain that  coordinates multiple aspects of cognition, including both motor and action planning, decision-making, motivation, reinforcement, and reward system.

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Randomized allocation

A type of allocation strategy in which participants are assigned to the arms of a clinical trial by chance.

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Radioligand

a radioactive substance that binds to a specific target in the body, allowing visualization of that target’s distribution and activity

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Protein

Protein builds, maintains, and replaces the tissues in your body. The building blocks of life.

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Premanifest / Prodromal

Prior to onset or diagnosis of movement symptoms.

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Placebo

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 they’re taking a pill that doesn’t work.

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PK - Pharmacokinetics

The movement of drugs through the body

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PD - Pharmacodynamics

The body’s biological response to drugs

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PET scan

Positron emission tomography which produces detailed 3-dimensional images of the inside of the body.

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Neuron

Brain cells that store and transmit information

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MRI

Magentic resonance imaging: A technique using powerful magnetic fields to produce detailed images and visualizes the structure of organs, tissues, and bones 

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mHTT

Mutant huntingtin protein. The protein produced by the faulty HD gene.

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Manifest

after HD diagnosis, or when symptoms are already showing

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Longitudinal study

A study where each participant is looked at several times over a time period – unlike a cross-sectional study, where each participant is looked at only once

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HTT

one abbreviation for the gene that causes Huntington’s disease. The same gene is also called HD and IT-15

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fMRI

functional MRI:As with MRI, a technique using powerful magnetic fields  but focusing on brain function by measuring and mapping changes in blood flow, revealing which areas of the brain are active during specific tasks or cognitive processes

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CSF - cerebrospinal fluid

A clear fluid produced by the brain, which surrounds and supports the brain and spinal cord.

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Efficacy

A measure of whether a treatment works or not

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ASO(Antisense oligonucleotides)

A type of gene silencing treatment in which specially designed DNA molecules are used to switch off a gene

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Biomarker

a test of any kind – including blood tests, thinking tests and brain scans – that can measure or predict the progression of a disease like HD. Biomarkers may make clinical trials of new drugs quicker and more reliable

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BDNF

Brain-derived neurotrophic factor: a growth factor that may be able to protect neurons in HD.

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Allele

one of the two copies of a gene

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Plasma

Liquid component of the blood.

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Gene

The basic unit of heredity passed from parent to child. Genes are made up of sequences of DNA and are arranged, one after another, at specific locations on chromosomes in the nucleus of cells.

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Phase

Clinical trial phases are different stages of research that assess the safety and effectiveness of a new medical treatment or intervention in humans.

Each phase has a specific goal and involves a different number of participants. Generally, there are 4 phases (I-IV), with Phase I focusing on safety and dosage, Phase II on efficacy and side effects, Phase III on comparing the new treatment with standard treatments, and Phase IV on long-term safety monitoring.