Access to the Right Participants — Through the Right Pathway
Early-phase clinical development requires more than access to participants. It requires access to the right participants, through the right pathway, in the right setting.
Accelsiors supports healthy volunteer, patient-based, and pediatric early-phase studies and, critically, helps sponsors determine which pathway best serves their programme at each stage.
For many first-in-human programs, healthy volunteer studies remain the most appropriate starting point, particularly for safety, tolerability, and PK characterization. Through our collaborating clinical research units, we offer rapid, reliable access to well-characterized healthy volunteer populations, supported by dedicated recruitment, screening, and retention infrastructure.
For compounds where the mechanism, the indication, or the risk profile requires patient exposure from the outset, Accelsiors provides access to patient populations through hospital-integrated clinical research environments. This enables early efficacy signal detection, pharmacodynamic biomarker assessment, and dose-response evaluation in the target population from the earliest feasible stage.
Pediatric early-phase development presents distinct challenges that go beyond simply adapting an adult protocol. Whether the program originates directly in a pediatric population, as is the case for conditions such as inborn errors of metabolism, rare pediatric genetic disorders, or other indications where adult data may not exist or apply, or whether it follows an adult-to-pediatric extrapolation path, the requirements are fundamentally different.
Dose logic in pediatric populations, particularly in neonates, infants, and young children, must account for developmental pharmacology, weight-based and maturation-based dosing models, and formulation constraints that do not arise in adult studies. Biomarker feasibility must be re-evaluated for pediatric settings, where sample volume limitations, assay sensitivity requirements, and ethical considerations around invasive sampling change the translational plan. Pediatric development programs must also navigate specific regulatory requirements, such as the Pediatric Investigation Plan (PIP) in Europe and pediatric study requirements under FDA frameworks, which introduce strategic, scientific, and timeline considerations that benefit from early integration into the development plan.
Accelsiors brings expertise in both pediatric development pathways:
- Nonclinical-to-pediatric-clinical transitions — where the program moves directly into a pediatric population without prior adult clinical data, requiring pediatric-specific dose rationale, safety modelling, and age-appropriate study design from the outset
- Adult-to-pediatric extrapolation programs — where existing adult PK, safety, and efficacy data are used to support pediatric dose selection and study design, often through modelling and simulation, bridging studies, and population PK approaches
Our collaborating clinical research environments include hospital-integrated settings with direct access to pediatric clinical departments, pediatric investigators, and the specialized oversight structures required for early-phase work in young populations. This is one of the clearest examples of why study-setting fit matters: pediatric early-phase work cannot be placed in a generic Phase I unit. It requires a setting where pediatric clinical expertise, ethical governance, and operational infrastructure are already embedded.
Many programs require a transition from healthy volunteer to patient-based studies, or from adult to pediatric populations, within the early-phase window. Accelsiors designs these progressions to preserve continuity, in data, in scientific logic, and in operational execution, so that each transition is a planned development step, not a disruptive operational reset.
