Rare Diseases CRO Services

Become a study of choice among patient communities

Patients want to join trials that not only meet their expectations, but exceed them — and that demands customized solutions delivered With Heart™. Our best-in-class team of rare disease experts are ready to tackle even the most complex trials with their clinical and regulatory expertise, while seamlessly aligning your study with the journey of the patient and caregiver.


Make every patient matter

Patients — not companies, regulators, healthcare providers, payers, or investors — are the people we ultimately serve. And we never lose sight of that. Through our Center of Excellence for Rare Diseases, we bring together cross-functional expertise to meet timelines, minimize patient burdens, and incorporate patient feedback throughout the trial. We also expedite site startup and study management, so rare disease patients have a better chance to enroll and potentially save or improve their quality of life.

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As the Global Head of Rare Disease, I oversee everything from the pre-award phase, working with our sales teams to come up with the best strategies for our clients to be able to best build out their programs, add in the knowledge and expertise that we've got in-house to complement what they need, particularly working with the biotech companies.

They often have some incredible experts but just need that extra support to get to the clinical development plan that's going to get through regulatory. The idea of the Center of Excellence was to bring our global expertise together into a functional unit. And on speaking to these experts, they have some incredible insights into the pitfalls, the challenges around how to get the data to a level of integrity where you can get it through the regulatory rigor and the challenges actually that we face in rare diseases.

From a drug developer perspective, the regulators face, so the same challenges. So, it was really interesting to have those insights into, you know, how they look at those same challenges and how we can overcome them. Because clinical development in rare disease is so condensed.

You quite often have one or two clinical trials, so you have to get it right first time. As we learn more and more and more about these rare diseases, the regulators are asking for more and more strict trial designs, and that's becoming a real challenge.

And then the second piece is the high cost, the high price of rare disease products. So again, to date, because rare diseases have been a huge unmet medical need.

The price of these therapeutics, particularly gene therapies, has been astronomically high. But as more of these products reach the market, it's becoming unsustainable.

So again, a lot of the conversations we're having is how can we price these products at a reasonable rate and be able to get the benefit for both patients, the payers, and the clients?

Experience in the past 5 years with rare diseases

clinical projects
enrolled patients

Advanced therapies

Eighty percent of rare diseases are known to have a genetic cause. That’s why we’ve built our rare disease capabilities upon deep experience and expertise in the strategic application of genetics in drug discovery and development. Each rare disease clinical trial for a gene therapy or gene-editing therapy is meticulously strategized and operationalized to ensure care of the patient and caregiver, while enabling the delivery team to be a steward of the investigational product.

Precision medicine

Clinical trials for precision medicines pose unfamiliar challenges, like qualifying patients for inclusion due to a specialized biomarker or because genetic testing is required. Our team is ready. We have an expansive bench of experts with direct pharmaceutical and biotech experience (including early-stage biomarker strategy development and genomics), complemented with a multidisciplinary approach to genomic real-world evidence strategy.

Scientific data organization

Our Scientific Data Organization aims to answer previously intractable research questions with a team of scientists, data stewards, solution architects, and informaticists using a quality and process overlay that empowers clinical research with real-world data. This team supports your research by exploring relevant methodologies, such as study feasibility, synthetic control arms, sensors/wearables, and machine learning.


Empathy that minimizes patient burden

We feel the imperative in rare disease settings to minimize the number of patients unable to gain access to potentially life-saving treatments. That’s why our real-world data experts help avoid or reduce the number of patients receiving current standard-of-care treatment in a trial. This process also reduces overall study timelines, getting your product into the hands of everyday patients more quickly.

Expertise for even the most complex trials

The way we integrate clinical and regulatory consulting gives us an advantage when tackling highly complex trials. We also combine an early advisory service of medical, regulatory, genomics, and biostatistical experts with an experienced multidisciplinary team and key technology partnerships to meet and exceed your goals.

Experience and operational efficiency

We bring extensive rare disease experience to projects, including support for rare populations — enabling us to apply previous insights throughout delivery and improve operational efficiency. All our functions are enhanced even further by our Parexel Academy Rare Disease certification program, which is available to you as well.



Prevalence of a disease determines if it is considered rare. The FDA defines rare disease as one that fewer than 200,000 in the U.S. live with. Different organizations around the world define rare disease slightly differently.

Selecting the right endpoints to establish clinical benefit is one of the most challenging aspects of rare disease drug development.

With rare diseases, often little is known about the condition’s natural course, and the experimental agent’s mechanism of action may not be fully illuminated. Additionally, patients are often difficult to locate, making it hard to power a study adequately enough to measure treatment effects.

Many companies wish pursue FDA Breakthrough Therapy Designation for drugs targeting rare disease. BTD has become a core component of the regulatory strategy for these drugs.

Choosing the appropriate strategy and timing for a BTD request is a crucial challenge for companies. To maximize the program’s advantages, a company should submit a BTD request as soon as possible, ideally before Phase 3 trials begin. When feasible, although uncommon, companies can seek BTD even based on Phase 1 findings. For example, at Parexel, our rare disease experts have helped clients design early phase clinical trials, such as dose-finding studies that include preliminary efficacy assessments to support BTD.

Our rare disease experts can help you navigate the complex regulatory landscape for rare disease drug development, as well as advise on all phases of clinical trials – including selecting optimal endpoints, engaging with patients, and utilizing innovation trial designs. Market access is another key area where our experts can provide guidance, including reimbursement challenges that may emerge.

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