Radiopharmaceuticals are transforming precision oncology

This article is part of Parexel's "Advancing radiopharmaceutical development" playbook series. This series offers insights across feasibility and site selection, patient-guided trail design, regulatory strategy, and supply chain and logistics management to support sponsors in this evolving market.  

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Beyond location and logistics: Defining RPT trial viability

The number of new clinical studies testing diagnostic, therapeutic, and theranostic RPTs in cancer indications has grown steadily since 2019: academic studies increased by 72 percent, and industry-sponsored trials jumped 64 percent.¹  Venture financing of RPTs more than quintupled in the five years ending in 2023,²  and multi-billion-dollar biotech acquisitions dominated RPT M&A news in 2024.³  The result is an increasingly crowded R&D landscape. RPT trials are expensive and require close coordination between isotope production, manufacturing, and clinical use, as well as nuclear medicine expertise and equipment. For example, sites must have access to positron emission tomography (PET) and single-photon emission computerized tomography (SPECT) scanners, and gamma counters to measure radiation emitted by radionuclides. 

Feasibility testing and site selection are essential to success in this competitive and complex environment. At Parexel, we use the following strategies to identify optimal RPT trial sites:

• Estimate the impact of radioactive material (RAM) licensing on site timelines.

The timeline for securing the necessary RAM licenses at the site level can be from a month to two years, depending in part on the country (Table 1). Conventional oncology trials have much shorter site activation timelines, and the contrast often surprises RPT sponsors we work with. Further, RAM licensing is not a blanket approval: Different radioligands, distinguished by their emission type (alpha, beta, gamma), often necessitate specific licenses. A site licensed for Actinium-225 (²²⁵Ac) might not automatically be approved for Indium-111 (¹¹¹In), creating a layer of complexity that demands meticulous planning and tracking. 

Recently, we performed a competitive landscape analysis for an emerging biotech company planning a first-in-human trial of an RPT to treat neuroendocrine cancer. We analyzed the more than 350 open and planned RPT trials globally, those with a similar completion date (about 75), and those that would directly compete for the same patients in their target geographies (15). Because the study required that every site have a RAM license for two radioisotopes, we advised them to focus on those with existing certification for the initial dose escalation stage of the study to avoid licensing delays. For the dose expansion stage of the trial, we advised adding sites as they obtained the required radioisotope-specific licenses. This gated strategy mitigates competition at frequently selected sites.

At Parexel, we rely on country-specific strategies to prevent delays caused by RAM licensing. For example, site-based nuclear medicine subcommittees in the United States often require final documentation, such as lab and pharmacy manuals, before they review and approve a trial submission (Table 1). It is critical in these cases to prepare and finalize documents well in advance. In the Netherlands, approval to conduct trials involving radioactive materials (RAM) must be obtained from the Authority for Nuclear Safety and Radiation Protection (ANVS). However, if a site does not have an existing ANVS certification, sponsors can submit an application in parallel to the mandatory EU Clinical Trial Regulation (EU-CTR) filing to ensure no delay to study-start-up timelines.

† Timeline impact is any additional time expected beyond the “standard” study start-up timelines expected for these review processes. These timelines are based on Parexel's experience conducting international RPT trials and, in some cases, information provided by the regulatory agencies referenced.

Key to acronyms: CIRB: centralized institutional review board; EC: ethics committee; EU-CTR: European Union Clinical Trial Regulation; IP: investigational product; IRB: institutional review board; RA: radioactive approval (committee names for this function vary by institution); RAM: radioactive material; RPT: radiopharmaceutical.

• Profile sites in advance to confirm RPT capabilities

Careful selection ensures that trial sites have the infrastructure to conduct RPT trials, such as PET and SPECT scanners, radiation therapy capabilities for radioligand handling, administration, and disposal capabilities. For example, radiation shielded rooms are used to isolate patients during and after they are diagnosed or dosed with RPTs, to allow radioactive elements to decay without harming site staff or patients’ family members. Investigational product (IP) waste containing ²²⁵Ac must be stored for 100 days, according to guidelines requiring safe storage for at least ten half-lives (the time it takes for half of the material to decay) of a radioactive element.⁴ 

At Parexel, we rely on our Oncology Site Alliance Network—supplemented by real-world data, census data, and AI-enhanced querying—to identify high-performing RPT trial sites with access to the necessary equipment and patients. We use detailed questionnaires to assess site capabilities and populate and update our database. Our inquiries go deeper than standard inquiries, probing the specific models of SPECT machines and the site's experience with handling and analyzing radioactive samples for different emission types. Our alliance members have consistent enrollment metrics and standard start-up documentation; these are crucial for rapid startups in institutions with long contracting timelines.

Our goal in building and curating a site relationship network is to make it as easy as possible to work with Parexel. For a contract research organization (CRO), sites must perceive you as a preferred and trusted partner. When we talk to sites, we are the intermediary between them and trial sponsors. We streamline the dialogue and make it a pleasant experience by having a single point of contact instead of a rotating cast of project personnel.

Academic hospitals and clinics are key components of any site list. A profiling step enables slick and efficient knowledge sharing. Is this site already at capacity? What is their next planned patient population or product for study? If a site is especially interested in prostate or breast cancer studies, we offer them these studies whenever possible. 

• Prioritize sites with nuclear medicine physicians who can collaborate. 

Our global footprint enables us to understand regional practices, such as the prevalence of nuclear medicine physicians as principal investigators (PIs) in certain European countries. Leveraging nuclear physicians in RPT clinical trials requires site-specific practice and process knowledge. We need to know whether nuclear physicians, radiation oncologists, and medical oncologists at each site work well together. 

The success of RPT trials also depends on the investigators’ expertise and enthusiasm for clinical research. So we identify PIs who are passionate about the field, overlay our knowledge of the site, relationships, and performance in past studies, and then reach out to engage those who are the best fit. Expanding the site pool to new regions can sometimes accelerate enrollment. For example, South Africa has few experienced RPT sites, but investigator interest is high. Including new sites and regions in early-stage trials, mentoring motivated PIs, and providing training are key.
 

Resources

1. Source: Parexel analysis of data from Citeline and clinicaltrials.gov.
2. Precision radiation opens a new window on cancer therapy, Nature Biotechnology (June 12, 2024).
3. 2025 forecast: As companies rush to radiopharmaceuticals for oncology, what's next? Fierce Pharma (January 10, 2025).
4. Precision radiation opens a new window on cancer therapy, Nature Biotechnology (June 12, 2024).

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