Our approach and expertise

At Parexel, our approach to neurology research is driven by a commitment to advancing our understanding of neurological disorders and developing effective treatments. We follow a comprehensive and multidisciplinary approach that integrates scientific expertise, innovative technologies, and global reach to support the development of new interventions and therapies for neurological conditions.

Amyotrophic lateral sclerosis (ALS)

As great strides are being made in managing ALS symptoms and complications, Parexel is focused on supporting our clients in their groundbreaking work in this area. Linking patients to clinical trials through their established care-delivery systems, we empower physicians to offer more treatment options, remove participant barriers, and connect with underserved communities.

For example, Parexel recently conducted a full-service placebo-controlled Phase II study for ALS patients to evaluate the efficacy, safety, and tolerability of a study drug. A tailored recruitment and retention strategy supported robust enrollment, resulting in 458 patients in more than 10 countries and 80 sites. In collaboration with the sponsor and sites, Parexel delivered this complex trial within 12 months, rigorously applying quality measures to ensure data integrity. Primary and key secondary endpoints were all statistically significant. This seminal trial set a precedent for methodology, design, and operational delivery in ALS research.

Parexel collaborates with sites including community centers and large academic centers of excellence, along with patient advocacy groups, high-impact institutions, and subject-matter experts, to bring novel therapies to patients and families. To reduce patient burden, we integrate decentralized clinical trial (DCT) solutions for ALS patients when appropriate. These include, for example, home visits and telemedicine, electronic patient-reported outcome devices and sensors, and reminders.

We have worked with more than 1,500 patients in more than 30 countries on ALS studies, Phase I–IV including first-in-human, with over 150 currently active sites.

Duchenne muscular dystrophy (DMD)

Finding treatments to manage symptoms and slow the course of the disease: this is the aspiration of our team while scientists continue to work on a cure for this debilitating condition. Having worked with hundreds of DMD patients at scores of sites, we bring extensive experience to every project, implementing best practices to protect DMD study endpoints. These include thorough assessments, sample collection, and imaging, supported by an integrated technology platform.

We collaborate every day with the Scientific Leaders Task Force to leverage researchers’ feedback in implementing innovative study designs and protocol optimization, and partner with patient advocacy groups. Specialized DMD vendor connections enable us to apply previous insights throughout trial delivery and improve operational efficiency. All of our functions and dedicated standard operating procedures are further enhanced by our Parexel Academy Rare Disease certification program.

We take great pride in our contributions to the first gene therapy for boys with DMD to be approved by the FDA in 2023. Parexel executed this project from Phase I to Phase III, generating statistically significant results in the primary endpoint.

We have worked with more than 700 DMD patients and over 100 unique sites, including four gene therapy products.


Epilepsy is one of the most active indications globally, with novel discoveries, treatment approvals, and new technologies on the near horizon. We are inspired to be the trusted partner in the evolution of novel therapies for people who live with epilepsy.

We regularly engage with strategic partners to deliver streamlined solutions with the right architecture to protect study endpoints. For example, Parexel recently collaborated with The Epilepsy Study Consortium to develop best practices for training and guidelines for sites to identify patients with stereotypical prolonged seizures who met study criteria. The global study enrolled more than 160 patients in North America, Europe, and Asia-Pacific, including China, using targeted recruitment tactics. We conducted recruitment in partnership with a strategic vendor that produced video electroencephalogram (V-EEG) equipment, training, and support.

Our in-house medical team comprises thought leaders in clinical practice for the care of epilepsy patients, with academic training at the top programs in the U.S. Deep experience extends to rare conditions such as epileptic encephalopathy, with projects across all phases including first in human. 

We advocate for a scientific-medical communication strategy to engage with key stakeholders, investigators, patient advocacy groups, and key opinion leaders to monitor changes in recommendations. These sources support us in identifying hubs of patients in underserved areas to participate in our programs. Our preference for epilepsy programs is to balance the need for on-site visits with the benefits of remote patient management to reduce the patient and site burden.

We have worked on studies across all phases including first-in-human involving more than 3,500 patients and 500 sites worldwide.

Memory care (Alzheimer’s disease, dementia)

Parexel has a well-established reputation for leadership in memory care, with a philosophy rooted in the critical importance of incorporating the voice of patients and caregivers in design of clinical trials. This focus on the patient is fundamental not only to the successful execution of the trials, but also to recruitment, which is notoriously challenging given the characteristics of the population. Our team is at the forefront of early identification of Alzheimer’s disease biomarkers in healthy older adults and best practices for making trials more accessible and inclusive.

On our staff are leading experts in Alzheimer’s disease, various forms of dementia, and Huntington’s disease, as well as other rare conditions. The neurologists on our team bring not only medical expertise, but experience in academic, clinical, and pharmaceutical settings.

For example, we recently conducted a pivotal Phase III study focused on advanced therapies for memory care. The study aimed to assess the slowing of Alzheimer’s disease progression compared with placebo in patients with mild cognitive impairment, involving more than 800 participants. We worked closely with partners on high-impact assessment (repetitive lumbar punctures, PET scans, and MRIs) for a subgroup, devising solutions for reducing screen failures and minimizing the need for lumbar punctures. These partners were instrumental in in rater training to accelerate study startup.

In recent years, we have conducted full-service studies from Phase I to Phase IV, working with more than 9,000 patients across many thousands of sites in countries worldwide

Myasthenia gravis (MG)

New treatments for myasthenia gravis are needed because conventional therapies have limitations, such as side effects and inadequate control of symptoms. Parexel is deeply involved in developing treatments for MG. Protection of study endpoints leads our clinical development strategy, focusing on rater consistency, data stability, and harmonized global execution. 

MG is a puzzle, and it starts before many patients and families begin a diagnosis. Once we have the diagnosis, the next questions are about the best treatment for the patient and the best way to provide care. To understand the burden of living with the disease and assess planned protocol complexities for clinical studies, Parexel’s Patient Insights team implemented a patient focus group to identify and collect feedback from MG patients. Our team created a solution for empowering caregivers, offering substantial scientific materials, flexible visits, and concierge solutions. This attention to the realities of those suffering from MG is instrumental to our approach.

Specifically, Parexel recently conducted a full-service global Phase III study for generalized MG patients. The study involved 200 patients, with a six-week treatment period followed by a 52-week open-label extension (OLE). To deliver on rater consistency, the sites assigned at least two study staff to conduct training for clinical assessments. Almost double the staff was required because of the high demand for attention from the sites and customization of the patients’ journey. The study was completed ahead of schedule.

Parexel is deeply involved in developing treatments for MD, conducting Phase I-IV studies with more than 1,200 participants across more than 50 countries and 250 active sites.

Parkinson’s disease (PD)

Breakthroughs in treatment and improved care are bringing hope to the community living with Parkinson’s disease. At Parexel, we are devoted to advancing the evolving research in identifying biomarkers for PD that can lead to earlier diagnosis and slow the progress of the disease. On our staff are thought leaders who are extensively published in the field. This leadership of course extends to our work in clinical trials.

For example, we are currently working on a cell and gene therapy for PD involving high-precision dosing. For a highly complex trial like this, we combine an early advisory service of medical, regulatory, genomics, and biostatistics experts with a multidisciplinary team and key technology partnerships.

In another recent project, we conducted a Phase III global program to identify best practices for studies in movement disorders. Fundamental to this study was long-term assessment of daytime PD motor symptoms and compliance. To overcome patient and caregiver discomfort with e-diaries, our targeted recruitment strategy used customized educational materials and deployed a compliance task force for follow-up. Thanks to technology, multiple sensors could be integrated in one wearable device, which helped us evaluate the movements of patients at home and collect the information directly. Endpoint collection drove key data on efficacy, leading to regulatory approval.

Our work in clinical trials encompasses more than 6,000 participants in full-service studies spanning more than 50 countries in hundreds of active sites.

Traumatic brain injury (TBI)

Conducting clinical trials for treatment of traumatic brain injury requires comprehensive strategies for site identification and selection, along with a thorough understanding of the complexities of study startup and the patient pathway. Equally important, of course, is deep experience in diagnosis and treatment types, along with a commitment to supporting the patient and caregiver journey and improving the study experience.

For TBI, recruitment depends largely on relationships with the sites. Toward that end, Parexel maintains a network of investigators highly experienced in neurology at hospitals and rehabilitation centers worldwide. This approach is augmented by external data sources to help identify capable sites. We work closely with patient advocacy groups such as the Brain Injury Association of America and Concussion Awareness Now on best practices for identifying, recruiting, and supporting patients with TBI.

Our strategy encompasses programs for spreading awareness among site personnel about how to contact the team on the hospital floor quickly when a patient arrives. After that point, communication is critical. We provide online tools and printed materials for site personnel, patients, family, and legal representatives to help them with informed consent and answer all questions clearly and thoroughly.

Our experience encompasses trials in the emergency room setting for brain inflammation, cerebral infarction, and neonatal brain injury. This work involves comprehensive coordination of the patient’s journey from arrival at the emergency room through triage and initial diagnosis, recovery, and at-home treatment and follow-up. 
In addition, we have extensive expertise in inhaled and nasal dosage products, conducting randomized studies with active and placebo arms. For example, we conducted a trial for a nasal dosage product that involved standardization of devices across the trial; training for patients, caregivers, nurses, and site staff; precise data collection; and full regulatory compliance.

Our team has conducted studies involving more than 1,000 patients at 100 sites across 15 countries. These include both adult and pediatric populations in Phase I-IV studies.