Exploring New Possibilities for
PARKINSON’S DISEASE
One small gene. One big REASON to learn about this clinical research study.


About the REASON Study
The REASON Study is evaluating the safety of an investigational drug, as compared to a placebo, designed to target the LRRK2 gene, potentially slowing the progression of Parkinson’s disease (PD).
The investigational drug is not approved by any regulatory authority as its safety and efficacy have not been established. A placebo is an inactive substance that looks like and is given the same way as the investigational drug.
LRRK2 stands for the leucine-rich repeat kinase 2 (LRRK2) gene, which is the gene responsible for the development of LRRK2 protein. Previous research studies have shown that one of the reasons for PD may be having too much LRRK2 protein in the brain.1
Researchers believe that by blocking some of the genetic instructions the body uses to create LRRK2, it may lead to decreased LRRK2 protein development, and a possible lessening of PD symptoms.2,3
The investigational drug or a placebo will be administered via injection into the lower back near the spine. The REASON Study will last approximately 18 to 62 weeks.

References:
- Di Maio R, Hoffman EK, Rocha EM, et al. LRRK2 activation in idiopathic Parkinson’s disease. Sci Transl Med. 2018;10(451):eaar5429. doi:10.1126/scitranslmed.aar5429
- Daher JP, Abdelmotilib HA, Hu X, et al. Leucine-rich Repeat Kinase 2 (LRRK2) Pharmacological Inhibition Abates α-Synuclein Gene-induced Neurodegeneration. J Biol Chem. 2015;290(32):19433-19444. doi:10.1074/jbc.M115.660001
- Daher JP, Volpicelli-Daley LA, Blackburn JP, Moehle MS, West AB. Abrogation of α-synuclein-mediated dopaminergic neurodegeneration in LRRK2-deficient rats. Proc Natl Acad Sci USA. 2014;111(25):9289-9294. doi:10.1073/pnas.1403215111

Who Can Join?
You may be eligible to participate if you:
- Are 35 to 80 years of age
- Were diagnosed with Parkinson’s disease in the last 7 years
- Are not currently receiving, or are on a stable dose of, oral Parkinson’s medication
- Other eligibility criteria apply
Why Take Part?
All eligible study participants will receive at no cost:
- Investigational drug or placebo
- All study-related visits and care
- Comprehensive study-related health evaluations and assessments
- Travel and reimbursement support
- Information and support from the study staff

What to Expect During the REASON Study
The REASON study includes two parts: Part A and Part B. Part A is now complete. Part B is 47 weeks. You will attend one scheduled overnight, inpatient visit at the study site to receive the investigational drug or a placebo and take part in study-related medical tests and assessments.
Study participants will be assigned to receive either the investigational drug or a placebo at random (by chance). A placebo is a substance that looks like the investigational drug but contains no actual active drug.
Study Participation and Your Safety
In clinical research studies, patient safety is the highest priority. Every study must be reviewed and monitored by either an Institutional Review Board (IRB) or an Independent Ethics Committee (IEC). These groups, made up of both scientists and non-scientists, review the study’s plan to make sure that:
- The rights of participants will be protected
- There are no unnecessary risks involved
- The study addresses important unanswered medical questions
During the study, a team of study doctors and nurses at the study site will closely monitor your health. If you have questions or concerns at any point throughout the study, a study staff member is available. The study staff can also tell you about their COVID-19 safety protocols.
Participation in a clinical research study is always voluntary. If you decide to participate, you may withdraw at any time and for any reason. If you decide not to participate, your decision will not affect the care you are receiving now or may receive in the future. Your privacy will be maintained throughout the study.
Contact a study site near you.
The information you provide will be kept confidential.
Portland, OR 97239
United States
Spokane, WA 99202
United States
(509) 960-2818 EXT. 709
Knoxville, TN 37920
United States
Farmington Hills, MI 48334
United States
Cleveland, OH 44195
United States
Philadelphia, PA 19104
United States
Chicago, IL 60611
United States
Travel and reimbursement support will be provided. Please ask the study staff for more information.
Frequently Asked Questions
This section will help answer some important questions you may have.
About the REASON Study
Previous research studies have shown that one of the reasons for PD may be having too much LRRK2 protein in the brain.1 The REASON Study is evaluating an investigational drug designed to potentially reduce how much LRRK2 is produced by blocking some of the genetic instructions the body uses to create this protein. Researchers believe this may lead to decreased LRRK2 protein development and a possible lessening of PD symptoms.2,3
The REASON Study is a phase 1 study, which means it is the first to test the investigational drug in humans. The study is evaluating the safety of an investigational drug, as compared to a placebo, for patients with PD. The goal of the clinical trial is to answer questions about the investigational drug’s safety and how it moves through the body.
Biogen is conducting the REASON Study. Biogen is a global biotechnology company located in Cambridge, Massachusetts.
Deciding to participate in a clinical research study is an important and personal decision. Before you agree to participate, the study team will review all aspects of the research study with you. You will be given a document called an Informed Consent Form that provides, in writing, the research study’s purpose, assessments, procedures, potential benefits, risks, and precautions. You will have the opportunity to ask questions and are encouraged to speak with your own physician and family to decide if taking part is right for you.
No, all study-related medical care and the study medication will be provided at no cost. You may be paid back for some of your transportation and other costs related to the study. The study staff can give you more information about this.
Yes. Study participants are assigned to receive either the investigational drug or a placebo at random (by chance). A placebo is a substance that looks like the investigational drug but contains no actual active drug.
In Part A, 3 in 4 (75%) of participants will receive the investigational drug, and 1 in 4 (25%) will receive a placebo. In Part B, 3 in 4 (75%) or 4 in 5 (80%) of participants will receive the investigational drug, and 1 in 4 (25%) or 1 in 5 (20%) will receive a placebo.
Yes, the information you provide will not be shared with anyone who is not directly associated with this research study without your permission, except as required by law or as set forth in the Informed Consent Form, the document you would sign before participating in the study.
No, your doctor does not have to give you permission to participate. However, feel free to talk to your doctor about participating in the study. With your permission, the study doctor will keep your regular doctor updated about your condition during the study.
Participation in a clinical research study is always voluntary. If you decide to participate, you may withdraw at any time and for any reason. If you decide not to participate, your decision will not affect the care you are receiving now or may receive in the future.
About Research Studies
A clinical research study is a scientific investigation designed to answer important questions about an investigational drug, such as:
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-
- Is it safe?
- Does it work?
- Which dose may work best?
- What are the side effects?
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Qualified doctors, nurses, and other medical professionals are responsible for conducting the study.
It is only through the completion of research studies that study medications can be evaluated and, if appropriate, approved for a particular use. Different regulatory bodies in different countries will provide this approval after a thorough review, like the US Food and Drug Administration (FDA). The safety and efficacy of prescription medications in use today were first established during research studies.
In order to ensure that a research study is ethical, and that patients’ rights are protected, Institutional Review Boards (IRBs) or Ethics Committees (ECs) review study protocols.
Only patients who meet all required eligibility criteria for a research study may take part. The study team at the study doctor’s office will review your medical history and current medical status against the eligibility criteria. They will determine if you are eligible to participate in the research study. You may also be asked to provide information from your medical records to help the study team determine whether you may be eligible.
An investigational drug is a drug that has not been approved by any regulatory authority; its safety and efficacy have not been established.
References:
- Di Maio R, Hoffman EK, Rocha EM, et al. LRRK2 activation in idiopathic Parkinson’s disease. Sci Transl Med. 2018;10(451):eaar5429. doi:10.1126/scitranslmed.aar5429
- Daher JP, Abdelmotilib HA, Hu X, et al. Leucine-rich Repeat Kinase 2 (LRRK2) Pharmacological Inhibition Abates α-Synuclein Gene-induced Neurodegeneration. J Biol Chem. 2015;290(32):19433-19444. doi:10.1074/jbc.M115.660001
- Daher JP, Volpicelli-Daley LA, Blackburn JP, Moehle MS, West AB. Abrogation of α-synuclein-mediated dopaminergic neurodegeneration in LRRK2-deficient rats. Proc Natl Acad Sci USA. 2014;111(25):9289-9294. doi:10.1073/pnas.1403215111