[68Ga]Ga-NeoB

Overview

[68Ga]Ga‑NeoB (NeoBOMB1) is an investigational PET radiopharmaceutical that targets the gastrin‑releasing peptide receptor (GRPR), which is overexpressed in several tumors (notably subsets of prostate and breast cancers, and some GIST). It has been evaluated as a diagnostic companion in GRPR‑directed theranostics (with [177Lu]Lu‑NeoB for therapy). Early human studies show feasible radiolabeling, favorable biodistribution/dosimetry, and lesion uptake in select GRPR‑positive tumors. (pubmed.ncbi.nlm.nih.gov)

Mechanism of action

NeoB is a high‑affinity GRPR antagonist peptide conjugated via DOTA to gallium‑68 for PET imaging. As an antagonist, it binds GRPR without inducing receptor agonist effects; high physiologic uptake occurs in the pancreas due to dense GRPR expression. (pubmed.ncbi.nlm.nih.gov)

Efficacy (diagnostic performance/readouts)

• Prostate cancer (first‑in‑human, feasibility): The initial description reported visualization of prostate cancer lesions in men using [68Ga]Ga‑NeoB PET/CT, supporting tumor targeting but without formal diagnostic accuracy metrics. (pubmed.ncbi.nlm.nih.gov)

• Gastrointestinal stromal tumors (phase I/IIa, MITIGATE; n=6): Primary endpoints were safety, biodistribution, and dosimetry. Tumor uptake consistent with GRPR expression was observed in 3 of 6 patients, with increasing lesion SUVmax over time (e.g., SUVmax 4.3–25.9 at ~2 h p.i.). (pubmed.ncbi.nlm.nih.gov)

• ER/PR‑positive, HER2‑negative breast cancer (prospective feasibility; n=20): [68Ga]Ga‑NeoB PET/CT was visually positive in 75% (15/20) vs 65% (13/20) for 18F‑FDG. Sites positive on [68Ga]Ga‑NeoB and negative on FDG were seen in 50% of staging patients and 42% of restaging patients; median lesion SUVmax was higher with [68Ga]Ga‑NeoB than with FDG (20.5 vs 7.4). These data support potential complementary value in this phenotype. (jnm.snmjournals.org)

Overall, human imaging evidence indicates specific lesion uptake in a subset of GRPR‑expressing tumors; larger, controlled studies are still needed to define sensitivity/specificity and impact on management. (pubmed.ncbi.nlm.nih.gov)

Safety

• In the MITIGATE phase I/IIa GIST study, single‑dose [68Ga]Ga‑NeoB (mean 174 ± 28 MBq, peptide mass 50 μg) was well tolerated in all six patients over 4 weeks of follow‑up. Dosimetry showed a mean effective dose of 0.029 ± 0.006 mSv/MBq; the highest organ dose was the pancreas (0.274 ± 0.099 mSv/MBq). (pubmed.ncbi.nlm.nih.gov)

• No serious adverse events attributable to [68Ga]Ga‑NeoB were reported in early clinical evaluations; safety experience remains limited to small cohorts. (pubmed.ncbi.nlm.nih.gov)

Additional notes

• Chemistry/formulation: Kit‑based preparation has yielded high radiochemical purity (>97%) in clinical settings. (pubmed.ncbi.nlm.nih.gov)
• Theranostic pairing: [68Ga]Ga‑NeoB is being used to select patients for investigational GRPR‑targeted therapy with [177Lu]Lu‑NeoB; therapeutic results are outside the scope here but motivate interest in NeoB imaging. (pubmed.ncbi.nlm.nih.gov)

Further reading

• Preclinical and first‑in‑human feasibility in prostate cancer: Theranostic perspectives with NeoBOMB1 (J Nucl Med, 2016). (pubmed.ncbi.nlm.nih.gov)
• Preclinical/translation package for 68/177Ga/Lu‑NeoBOMB1 (J Nucl Med, 2017). (pubmed.ncbi.nlm.nih.gov)
• Phase I/IIa MITIGATE study in GIST: safety, biodistribution, dosimetry, and lesion uptake (J Nucl Med, 2020; full text). (jnm.snmjournals.org)
• Prospective ER/PR‑positive breast cancer study: diagnostic potential vs FDG (J Nucl Med, 2025). (jnm.snmjournals.org)
• Background review on GRPR‑targeted PET ligands including NeoBOMB1 (Cancer Imaging, 2024). (cancerimagingjournal.biomedcentral.com)

Notes on scope: The studies above focus on diagnostic use of [68Ga]Ga‑NeoB; no therapeutic efficacy outcomes apply to this imaging agent. Clinical evidence remains early‑phase with small cohorts; larger trials will be needed to establish diagnostic accuracy and clinical utility. (pubmed.ncbi.nlm.nih.gov)

Last updated: Oct 2025