Phase II Trial Assessing the Repeatability and Tumor Uptake of [68Ga]Ga-HER2 Single-Domain Antibody PET/CT in Patients with Breast Carcinoma

Human epidermal growth factor receptor 2 (HER2) status is used for decision-making in breast carcinoma treatment. The status is obtained through immunohistochemistry or in situ hybridization. These two methods have the disadvantage of necessitating tissue sampling, which is prone to error due to tumor heterogeneity or interobserver variability. Whole-body imaging might be a solution to map HER2 expression throughout the body. Methods: Twenty patients with locally advanced or metastatic breast carcinoma (5 HER2-positive and 15 HER2-negative patients) were included in this phase II trial to assess the repeatability of uptake quantification and the extended safety of the [68Ga]Ga-NOTA-anti-HER2 single-domain antibody (sdAb). The tracer was injected, followed by a PET/CT scan at 90 min. Within 8 d, the procedure was repeated. Blood samples were taken for antidrug antibody (ADA) assessment and liquid biopsies. On available tissues, immunohistochemistry, in situ hybridization, and mass spectrometry were performed to determine the correlation of HER2 status with uptake values measured on PET. If relevant preexisting [18F]FDG PET/CT images were available (performed as standard of care), a comparison was made. Results: With a repeatability coefficient of 21.8%, this imaging technique was repeatable. No clear correlation between PET/CT uptake values and pathology could be established, as even patients with low levels of HER2 expression showed moderate to high uptake. Comparison with [18F]FDG PET/CT in 16 patients demonstrated that in 7 patients, [68Ga]Ga-NOTA-anti-HER2 shows interlesional heterogeneity within the same patient, and [18F]FDG uptake did not show the same heterogeneous uptake in all patients. In some patients, the extent of disease was clearer with the [68Ga]Ga-NOTA-anti-HER2-sdAb. Sixteen adverse events were reported but all without a clear relationship to the tracer. Three patients with preexisting ADAs did not show adverse reactions. No new ADAs developed. Conclusion: [68Ga]Ga-NOTA-anti-HER2-sdAb PET/CT imaging shows similar repeatability to [18F]FDG. It is safe for clinical use. There is tracer uptake in cancer lesions, even in patients previously determined to be HER2-low or -negative. The tracer shows potential in the assessment of interlesional heterogeneity of HER2 expression. In a subset of patients, [68Ga]Ga-NOTA-anti-HER2-sdAb uptake was seen in lesions with no or low [18F]FDG uptake. These findings support further clinical development of [68Ga]Ga-NOTA-anti-HER2-sdAb as a PET/CT tracer in breast cancer patients.

Phase I Study of [68Ga]Ga-Anti-CD206-sdAb for PET/CT Assessment of Protumorigenic Macrophage Presence in Solid Tumors (MMR Phase I)

Macrophages play an important role throughout the body. Antiinflammatory macrophages expressing the macrophage mannose receptor (MMR, CD206) are involved in disease development, ranging from oncology to atherosclerosis and rheumatoid arthritis. [68Ga]Ga-NOTA-anti-CD206 single-domain antibody (sdAb) is a PET tracer targeting CD206. This first-in-human study, as its primary objective, evaluated the safety, biodistribution, and dosimetry of this tracer. The secondary objective was to assess its tumor uptake. Methods: Seven patients with a solid tumor of at least 10 mm, an Eastern Cooperative Oncology Group score of 0 or 1, and good renal and hepatic function were included. Safety was evaluated using clinical examination and blood sampling before and after injection. For biodistribution and dosimetry, PET/CT was performed at 11, 90, and 150 min after injection; organs showing tracer uptake were delineated, and dosimetry was evaluated. Blood samples were obtained at selected time points for blood clearance. Metabolites in blood and urine were assessed. Results: Seven patients were injected with, on average, 191 MBq of [68Ga]Ga-NOTA-anti-CD206-sdAb. Only 1 transient adverse event of mild severity was considered to be possibly, although unlikely, related to the study drug (headache, Common Terminology Criteria for Adverse Events grade 1). The blood clearance was fast, with less than 20% of the injected activity remaining after 80 min. There was uptake in the liver, kidneys, spleen, adrenals, and red bone marrow. The average effective dose from the radiopharmaceutical was 4.2 mSv for males and 5.2 mSv for females. No metabolites were detected. Preliminary data of tumor uptake in cancer lesions showed higher uptake in the 3 patients who subsequently progressed than in the 3 patients without progression. One patient could not be evaluated because of technical failure. Conclusion: [68Ga]Ga-NOTA-anti-CD206-sdAb is safe and well tolerated. It shows rapid blood clearance and renal excretion, enabling high contrast-to-noise imaging at 90 min after injection. The radiation dose is comparable to that of routinely used PET tracers. These findings and the preliminary results in cancer patients warrant further investigation of this tracer in phase II clinical trials.

Abstract P3-02-05: Assessment of repeatability and uptake quantification of 68GaNOTA-anti-HER2 sdAb PET/CT in patients with locally advanced or metastatic breast cancer

Background: Human epidermal growth factor receptor 2 (HER2) status is an important predictive biomarker in breast cancer (BC). Tumor heterogeneity has been described, with changes in HER2 expression levels between lesions and over the disease course. HER2 expression is assessed on tissue biopsies, at primary diagnosis and in metastatic lesions. A whole-body imaging technique such as PET/CT could help understand expression levels in different lesions. A 68Ga-labeled single domain antibody (sdAb) targeting the HER2 receptor has been developed and proven safe (Keyaerts et al., 2016). Imaging is performed at 90 min post-injection (pi). We report results of a phase II trial to assess the repeatability of the technique in 20 patients and the correlation of tracer uptake with HER2 tissue expression of the lesions present at the time of imaging. Methods: Twenty patients (pts) with a locally advanced or metastatic BC with at least one lesion of minimum 12 mm were included. Pts were injected intravenously with a typical protein mass of 100 µg and a radioactive dose ranging from 98-168 MBq 68GaNOTA-anti-HER2 sdAb. PET/CT images were obtained at 90 min pi. A second tracer injection followed by PET/CT was done with a maximal interval of 8 days. To assess repeatability, up to 5 lesions per pt were selected, with no more than 2 in a single organ. Peak Standard Uptake Values (SUVpeak) of the lesions were measured on both scans and compared with a t-test and Bland-Altman Plots. Images were compared to other available medical or imaging data and interpreted considering the subject’s disease course. Serum and plasma samples were collected before injection and between 60 and 365 days pi and stored for future detection of anti-drug antibodies (ADA) and liquid biopsies analysis for the presence of HER2 amplification. Tissue samples were assessed by central labs using mass spectrometry, immunohistochemistry and in fluorescence situ hybridization. Results: Twenty women with BC (6 HER2+, 14 HER2-) with a mean age of 58.6 y (37-81) were included. Three pts were scanned only once (2 due to withdrawal of consent, 1 due to covid pandemic). Repeatability of the technique was visually scored as excellent. For quantification, 50 lesions were compared on both scans in 17 pts without significant differences between the two measurements (p=0.40). The repeatability coefficient (RC) was 38.2%. The mean absolute percentage difference (MAPD) was 13.6%, comparable to repeat values reported for 18F-FDG. In 3 out of 6 HER2-positive (HER2+) patients, lesions showed high uptake, even better visible than using 18F-FDG in 2 of them. In 2 HER2+ subjects with a negative scan, lesions were confirmed to be true negatives: one patient did not relapse from BC but had tuberculosis; the other was confirmed to have a radiopneumonitis after radiotherapy and no relapse. In 1 HER2+ patient, the uptake was unexpectedly low. However, the HER2 status was also not reconfirmed in the metastatic setting for this subject. In 1 HER2-negative patient, the tumor HER2 status was changed from negative to positive based on a subsequent image-guided biopsy performed in this study. High tracer uptake was also seen in many of the patients presenting with HER2-low BC (IHC 1+ or 2+), indicating the potential of the tracer to detect low-level HER2 expression. Additional correlation to centrally performed tissue and blood analysis is ongoing. Conclusion: 68GaNOTA-Anti-HER2 PET/CT shows high uptake in HER2-expressing BC lesions but also in HER2-low lesions. The technique shows good repeatability and, in some cases, even better sensitivity than 18F-FDG PET/CT. Specificity was confirmed in relapse-free lesions such as tuberculosis and radiopneumonitis. Its sensitivity makes it a promising technique to assess HER2+ and HER2-low lesions in BC patients.

Citation Format: Odrade Gondry, Catarina Xavier, Wim Waelput, Omar Al Dabssi, Marian Vanhoeij, Sandrine Aspeslagh, Sofie Joris, Christel Fontaine, Guy Verfaillie, Jacques De Grève, Katrien Glorieus, Ine Luyten, Frederik Vandenbroucke, Sophie Bourgeois, Laurens Raes, Sheeno Thyparambil, Nick Devoogdt, Ilse Vaneycken, Julie Cousaert, Vicky Caveliers, Hendrik Everaert, Tony Lahoutte, Marleen Keyaerts. Assessment of repeatability and uptake quantification of 68GaNOTA-anti-HER2 sdAb PET/CT in patients with locally advanced or metastatic breast cancer [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P3-02-05.

The Prognostic Value of CD206 in Solid Malignancies: A Systematic Review and Meta-Analysis

Simple Summary

The role of innate immune cells in the tumor microenvironment (TME), more specifically the presence of the tumor associated macrophages (TAMs), is becoming more important in the prognosis and treatment of patients diagnosed with malignancies. The aim of this systematic review and meta-analysis was to assess the potential prognostic value of CD206-expressing TAMs, a subclass of macrophages, which were previously proposed to negatively impact the patient’s prognosis. We identified 27 manuscripts describing the role of CD206 in patient prognosis for 14 different tumor types. Despite a large heterogeneity in the results, we identified a significantly worse overall and disease-free survival for patients with increased CD206-expressing TAMs in the TME. The use of CD206-expressing TAMs could therefore be used as a prognostic marker in patients diagnosed with solid malignancies.

Abstract

An increased presence of CD206-expressing tumor associated macrophages in solid cancers was proposed to be associated with worse outcomes in multiple types of malignancies, but contradictory results are published. We performed a reproducible systematic review and meta-analysis to provide increased evidence to confirm or reject this hypothesis following the Preferred Reporting Items for Systematic Reviews and Meta-analyses statement. The Embase, Web of Science, and MEDLINE-databases were systematically searched for eligible manuscripts. A total of 27 papers studying the prognostic impact of CD206 in 14 different tumor types were identified. Meta-analyses showed a significant impact on the overall survival (OS) and disease-free survival (DFS). While no significant differences were revealed in progression-free survival (PFS) and disease-specific survival (DSS), a shift towards negative survival was correlated with increased CD206-expresion. As a result of the different tumor types, large heterogeneity was present between the different tumor types. Subgroup analysis of hepatocellular carcinoma and gastric cancers revealed no heterogeneity, associated with a significant negative impact on OS in both groups. The current systematic review displays the increased presence CD206-expressing macrophages as a significant negative prognostic biomarker for both OS and DFS in patients diagnosed with solid cancers. Because a heterogenous group of tumor types was included in the meta-analysis, the results cannot be generalized. These results can, however, be used to further lead follow-up research to validate the specific prognostic value of CD206 in individual tumor types and therapeutic approaches.

A Comprehensive Analysis of Baseline Clinical Characteristics and Biomarkers Associated with Outcome in Advanced Melanoma Patients Treated with Pembrolizumab

Simple Summary

Pembrolizumab, a monoclonal antibody targeting programmed cell death 1, improves the survival of patients with advanced melanoma. This study aimed to investigate the association of baseline clinical characteristics, laboratory and imaging variables, and gene expression profiling scores on tumor tissue analysis of advanced melanoma patients who were treated with pembrolizumab, with survival using univariate and multivariate analysis. Baseline organ function (reflected by the presence of active brain metastases, number of metastatically affected organs, albumin) and systemic inflammatory/immunologic status (reflected by albumin, C-reactive protein, absolute lymphocyte count, neutrophil-to-lymphocyte ratio) are the most important clinical and/or laboratory parameters predictive of survival. Novel biomarkers include the baseline presence of BRAF^V600 or NRAS^Q61/G12/G13 mutant circulating tumor DNA and baseline total metabolic tumor volume assessed by whole-body ¹⁸F-FDG-PET/CT. Gene expression profiling scores by the NanoString PanCancer IO360 panel were not conclusive in our patient population.

Abstract

Background: Pembrolizumab improves the survival of patients with advanced melanoma. A comprehensive analysis of baseline variables that predict the benefit of pembrolizumab monotherapy has not been conducted. Methods: Survival data of patients with advanced melanoma who were treated with pembrolizumab in a single university hospital were collected. A multivariate Cox regression analysis was performed to correlate baseline clinical, laboratory, and radiologic characteristics and NanoString IO360 gene expression profiling (GEP) with survival. Results: 183 patients were included (stage IV 85.2%, WHO performance status ≥1 31.1%; pembrolizumab first-line 25.7%), of whom 112 underwent baseline ¹⁸F-FDG-PET/CT imaging, 58 had circulating tumor DNA (ctDNA) assessments, and GEP was available in 27 patients. Active brain metastases, a higher number of metastatic sites, lower albumin and absolute lymphocyte count (ALC), higher C-reactive protein (CRP) and neutrophil-to-lymphocyte ratio, higher total metabolic tumor volume (TMTV), and higher ctDNA levels were associated with worse survival. Elevated lactate dehydrogenase (LDH) ≥ 2ULN (upper limit of normal), CRP ≥ 10ULN, or ALC < 750/mm³ delineate a subpopulation where treatment with pembrolizumab is futile. A TMTV ≥ 80 mL encompassed 17/21 patients with LDH ≥ 2ULN, CRP ≥ 10ULN, or ALC < 750/mm³. No significant associations were observed between baseline GEP scores and survival. Conclusion: Multiple baseline variables correlate with survival on pembrolizumab. TMTV is a more comprehensive baseline biomarker than CRP, LDH, or ALC in predicting the futility of pembrolizumab.

Baseline biomarkers correlated with outcome in advanced melanoma treated with pembrolizumab monotherapy

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Background: Pembrolizumab (PEMBRO) improves survival in advanced melanoma (MEL). This research investigates baseline (BL) biomarkers that predict long-term benefit on PEMBRO monotherapy. Methods: Outcome data on patients (pts) with advanced cutaneous/mucosal MEL treated with PEMBRO in our institution were collected after pt consent. Responses were evaluated using the immune-related response criteria. Total metabolic tumor volume (TMTV), assessed by 18-fluorodeoxyglucose positron emission tomography/computed tomography, was calculated as the sum of all tumor-associated voxels with a standardized uptake value (SUV) above the mean SUV measured in a reference region in normal liver tissue plus 3 standard deviations using Syngo.via software (Siemens Healthcare). The NanoString PanCancer IO360 panel was used for gene expression profiling (GEP). Results: A total of 196 pts was included in this analysis (median age 60; cutaneous 86%, mucosal 3%, unknown primary 12%; stage III 14%, IV-M1a/b/c 60%, IV-M1d 26%; first-line 24%). Median progression-free survival (PFS) in the population was 20.4 w (95% CI 10.2-30.7); median overall survival (OS) was 143.6 w (95% CI NR-NR). BL WHO Performance Status (PS) > 0 (HR 1.63 [95% CI 1.13-2.37]), C-reactive protein (CRP) > ULN (HR 1.92 [95% CI 1.33-2.77]), absolute lymphocyte count (ALC) < 750/mm³ (HR 2.45 [95% CI 1.32-4.55]) and > 1 metastatic site (HR 1.84 [95% CI 1.23-2.77]) were associated (P≤0.01) with worse PFS in multivariate analysis (Cox regression); BL WHO PS > 0 (HR 2.77 [95% CI 1.82-4.24]), lactate dehydrogenase (LDH) > ULN (HR 1.80 [95% CI 1.16-2.79]) and > 1 metastatic site (HR 1.95 [95% CI 1.16-3.25]) were associated with worse OS (P≤0.011). BL TMTV data were available in 118 pts (60%): BL CRP > ULN (HR 1.83 [95% CI 1.13-2.96]), ALC < 750/mm³ (HR 2.49 [95% CI 1.02-6.08]), > 1 metastatic site (HR 1.71 [95% CI 1.04-2.82]) and BL corticosteroid use (HR 4.62 [95% CI 1.38-15.45]) were associated with worse PFS (P < 0.05). BL WHO PS > 0 (HR 2.82 [95% CI 1.57-5.08]), ALC < 750/mm³ (HR 2.62 [95% CI 1.06-6.51]), history of brain metastases (HR 2.59 [95% CI 1.37-4.91]) and TMTV > 80 mL (HR 3.56 [95% CI 1.82-6.95]) were all associated with worse OS (P≤0.038). GEP data on a representative BL tumor sample were available in 27 pts (14%). Higher apoptosis signature scores were associated with increased probability of OS (HR 0.45 [95% CI 0.33-0.73], P < 0.01). Conclusions: BL TMTV > 80 mL identifies a subgroup of advanced MEL pts with worse outcome on PEMBRO. Increased apoptosis gene signature scores in a subset of patients predict increased OS.