PET Study of Breast Cancer Patients Using [68Ga]ABY-025

Open-labeled, exploratory, single center study.

• Group 1 (dose-finding) Six subjects with HER2-positive primary tumor status and four subjects with HER2-negative status. [68Ga]ABY-025 PET with low dose (100 μg) of ABY-025 peptide is performed, followed by a repeated PET within three weeks using high dose (500 μg) ABY-025 peptide (radioactivity maximum 500 MBq). A third [68Ga]ABY-025 PET will be performed in the HER2-positive subgroup only, when signs of progressive disease are found at routine clinical evaluation or else latest after 12 months regardless of disease status, then using the ABY-025 peptide dose previously determined to be preferable.
• Group 2 Ten subjects with HER2-positive primary tumor status. [68Ga]ABY-025 PET is performed using the ABY-025 peptide dose determined to be preferable during the dose-finding part of the study, followed by a second [68Ga]ABY-025 PET investigation at signs of progressive disease or else latest after 9 months.

Inclusion criteria

• Subject is > 18 years of age
• Diagnosis of invasive breast cancer with metastases
• Availability of results from HER2 status previously determined on material from the primary tumor, either

• HER2-positive, defined as a DAKO HercepTest™ score of 3+ or FISH positive or
• HER2-negative, defined as a DAKO HercepTest™ score of 0 or 1+ or else; if 2+ then FISH negative
• Volumetrically quantifiable metastasis lesions on CT or MRI, with at least one lesion >= 10 mm in smallest diameter and suitable for biopsy
• ECOG performance status of =< 2
• Life expectancy of at least 12 weeks
• Hematological, liver and renal function test results within the following limits:

White blood cell count: > 2.0 x 10^9/L Haemoglobin: > 80 g/L Platelets: > 50.0 x 10^9/L ALT, ALP, AST: =< 5.0 times Upper Limit of Normal Bilirubin =< 2.0 times Upper Limit of Normal Serum creatinine: Within Normal Limits or else normal clearance

• A negative pregnancy test (serum beta-human chorionic gonadotropin, beta-HCG) at screening for all female patients of childbearing potential, who must use a medically acceptable form of contraception from study start until at least 30 days after study termination
• Subject is able to participate in the diagnostic investigations to be performed in the study
• Informed consent

Exclusion criteria

• Manifest second, non-breast malignancy
• Known HIV positive or chronically active hepatitis B or C
• Administration of other investigational medicinal product within 30 days of screening
• Ongoing toxicity > grade 2 from previous standard or investigational therapies, according to US National Cancer Institute's "Common Terminology Criteria for Adverse Events v4.0 [CTCAE]"
• Other ongoing severe disease that may influence the patient's ability to participate in the study
• Pregnant or breast-feeding