Normal-Organ Absorbed Dose and Response Assessment in α-Particle Radiopharmaceutical Therapy

Area of Science:

• Oncology
• Medical Physics
• Radiopharmaceutical Therapy

Background:

• Alpha-particle radiopharmaceutical therapy (α-RPT) is a promising cancer treatment.
• Clinical development is limited by scarce patient-level dosimetry, toxicity, and response data.
• Challenges include imaging constraints, daughter redistribution, heterogeneity, and RBE modeling uncertainty.

Purpose of the Study:

• To review normal organ dose and response assessment in α-RPT.
• To propose a two-stage framework for study design and data collection.
• To accelerate the development of organ toxicity reference levels in α-RPT.

Main Methods:

• Literature review on normal organ dose and response in α-RPT.
• Proposal of a two-stage framework: Stage I (whole-organ dosimetry for safety) and Stage II (small-scale dosimetry for heterogeneity).
• Development of practical recommendations for imaging, dosimetry, toxicity endpoints, and data interpretation.

Main Results:

• A structured framework to guide α-RPT clinical trial design and data collection.
• Emphasis on standardizing dosimetry and toxicity assessments.
• Identification of key factors for developing biologically informed organ toxicity reference levels.

Conclusions:

• The proposed framework aims to standardize data collection in early-phase α-RPT trials.
• This standardization will facilitate the development of reliable organ toxicity reference levels.
• Addressing dosimetry and heterogeneity is crucial for advancing α-RPT safety and efficacy.