Clinical trials

Estrogen Receptor (ER) is a crucial prognostic factor and treatment target in breast cancer patients. Knowledge of its status greatly influences the choice of the optimal course of treatment. Pathological evaluations of primary tumor, axillary nodes, and metastases are the only confirmatory approach to ER status determination and are limited to known and accessible sites. However, it is known that many advanced breast cancer patients harbor diseases presenting inter-tumor or temporal ER heterogeneity, as ER expression can vary between tumor foci and can evolve during treatment and at time of recurrence, hence the need for whole-body, non-invasive assessment of ER status. In the last decades, 16α-\[18F\]fluoroestradiol (FES) was developed and evaluated as an ER-targeting positron emission tomography (PET) tracer. FES correlated with ER expression, and recently was shown to be able to predict hormone therapy response. Our Center designed and evaluated 4-fluoro-11β-methoxy-16α-\[18F\]fluoroestradiol (4FMFES), a successor PET tracer for ER imaging. Paired comparison during a phase II clinical trial showed that 4FMFES produced images of better quality, with less overall non-specific signal than FES. It resulted in a significantly improved tumor contrast and tumor detectability using 4FMFES-PET leading to increased diagnosis confidence in early-stage breast cancer compared to FES-PET. Those results demonstrated that, as of now, 4FMFES-PET is the best imaging modality worldwide for whole-body ER status determination, but further validations are necessary to position this method as a standard and essential tool for breast cancer management. Like what was observed for FES-PET, preliminary data suggest that 4FMFES-PET combined with FDG-PET will yield very high sensibility for breast tumor detection, each method being complementary. In continuity with previous work, we seek to expand our clinical knowledge of this high-potential diagnostic imaging through the following main objective: Launch a phase II clinical trial to explore the full potential and benefit of 4FMFES-PET in combination with FDG-PET for advanced ER+ breast cancer patients to demonstrate it is an essential tool for cancer management. This proposed project will focus on 3 specific aims: 1. Compare and complement 4FMFES-PET with FDG-PET and conventional imaging modalities, and evaluate how they improved prognosis and staging of ER+ advanced breast cancer patients; 2. Correlate 4FMFES/FDG uptake and staging with pathological data (histology, receptor status, grade), including distal biopsy metastases sampling; 3. Correlate 4FMFES/FDG uptake and staging with longitudinal outcomes (treatment response, progression-free survival, time-to-relapse) to determine which cohort of patient benefit most from 4FMFES.

Neuroblastoma is the most frequent extracranial childhood tumor, with an annual incidence of approximately 10.2 per million children. Staging of the disease can be done by different imaging strategies (CT, MRI, scintigraphy and PET/CT). Discrepancies may be observed among these different strategies resulting in different treatment strategies. The goal of this study is to assess the feasibility and safety of 68Ga-DOTATATE and to compare it to 123I-MIBG when investigating neuroblastoma.

A strategy to target the oncogenic receptor HER2 using a version of the anti-HER2 therapeutic antibody trastuzumab coupled to desferrioxamine (DFO) and radiolabeled with zirconium-89 (\[89Zr\]-DFO-trastuzumab) has been successfully evaluated in our group in preclinical settings. Clinical studies by other groups in recent years have shown the potential of targeting HER2+ lesions with \[89Zr\]-DFO-trastuzumab in patients with HER2+ cancers. We now want to establish the diagnostic potential of a protocol adding \[89Zr\]-DFO-trastuzumab PET imaging to FDG PET already used in the clinic for the detection of HER2-expressing cancers, including low expression levels considered until now as HER2-negative (HER2-low, IHC score 1+ and 2+ without FISH amplification of the HER2 locus). The HER2-low status has recently gained relevance thanks to large studies showing the efficacy of immunotherapy combined with drugs such as Enhertu (trastuzumab-deruxtecan), while trastuzumab alone was traditionally only effective for HER2+ cancers (IHC score 2+/FISH+, or 3+). In particular, we aim to develop a method to assess whole-body intertumoral heterogeneity in HER2 expression in order to detect cases with heterogeneous diseases and thus better stage patients and guide the optimal choice of personalized and targeted treatment to use. More specifically, the project aims to image with \[89Zr\]-DFO-trastuzumab PET patients with cancer, particularly breast cancer, but also esophageal, gastric, ovarian, endometrial and lung cancer, and whose primary tumor status is HER2-low.

This clinical trial is a pragmatic study aiming to evaluate the innocuity/safety profile of the PET radiotracer 68Ga-DOTA-TATE, and to establish the procedure as a routine standard-of-care diagnostic tool for all neuro-endocrine cancer patients. It is a single-center study, but with recruitment across all Canada. The trial is prospective, non-randomized, open-label and with no control group. The superiority of this procedure over the former standard-of-care (Octreoscan) was already established in previous and numerous studies across the world. As such, the current trial aims to gather data to further support the implementation of 68Ga-DOTA-TATE as the new standard-of-care for neuro-endocrine tumors (NET).

This project aims to monitor the innocuity/safety profile of cyclotron-produced \[68Ga\]-PSMA-617 PET imaging in PSMA-expressing cancers. It is a single-site, pragmatic, non-randomized and open-label study, with no control group. Although prostate cancers constitute the usual recommended population for this PET modality, recent evidences suggest that most solid tumors express substantial amount of PSMA in their neovasculature. As such, all cancers (excluding non-solid cancers) will be eligible for \[68Ga\]-PSMA-617 PET imaging in this trial, for as long as their tumors express PSMA. This study also aims to instigate the use of \[68Ga\]-PSMA-617 in the routine standard-of-care for detection and follow-up of eligible cancers. FInally, this project seeks to gather information about the impact on patient management this novel PET modality will have over the current standard-of-care.