Receptor diagnostics for advanced breast cancer. Results of a pilot clinical trial are promising

- This achievement is of special significance to me, since my adventure with the affibody-based ABY-025 radiolabeled tracer began back in 2006 in Jack Capala's lab at the National Cancer Institute in Bethesda, USA. I am proud that I was able to apply this tracer clinically," says Prof. Gabriela Kramer-Marek, head of the Department of PET Radiopharmacy and Laboratory Imaging at the Gliwice branch of the Maria Sklodowska-Curie National Cancer Institute - National Research Institute.

Prof. Gabriela Kramer-Marek, along with a team of clinicians and scientists from the National Cancer Institute in Gliwice: Anna Kastelik-Hryniewiecka, M.D., from the Department of PET Radiopharmacy and Laboratory Imaging, Michal Jarząb, M.D., Ph. Marcin Kubeczko of the Center for Breast Disease Diagnosis and Treatment, and Andrea d'Amico, M.D., and Izabela Gorczewska, M.D., of the Department of Nuclear Medicine and Oncologic Endocrinology, are exploring innovative ways to use immuno-PET imaging to predict treatment response in breast cancer patients. The doctors are focusing specifically on a protein called the human epidermal growth factor receptor (HER2), which plays a key role in promoting cancer cell growth. Breast cancers with elevated levels of HER2 are more aggressive, have a higher risk of spreading and often respond less well to treatment.

- Doctors recommend testing any invasive breast cancer for HER2, as this can greatly influence decisions about further treatment. HER2 testing is usually performed in a hospital laboratory using a tissue sample taken from the breast cancer during biopsy or surgery. Results are usually available within 1-3 weeks, but invasive tumor biopsies, commonly performed to assess HER2 status, can give an incomplete picture due to the heterogeneity of receptor expression, which can occur in different areas of the tumor, explains Prof. Gabriela Kramer-Marek.

Several therapies targeting the HER2 receptor (herceptin is the best known) are currently approved, but their outcome in individual patients depends on the status of this receptor in the tumor. At the National Cancer Institute in Gliwice, clinicians and researchers have used PET radioimmunoassay to image the HER2 receptor.

- This gives us the ability to visualize receptor activity throughout the tumor and throughout the patient's body. In addition, these imaging studies can be repeated to monitor changes in receptor activity during treatment," says Prof. Kramer-Marek.

The radioantigenic agent studied by the Gliwice doctors is based on an affibody molecule - a small protein designed to bind with high affinity and specificity to the molecular target, which is the HER2 receptor. Using this method, the receptor can be detected within an hour after its application, rather than after several days, as is the case with its activity in tissue specimens taken from a cancerous tumor. Importantly, this radiolabel does not interfere with the binding process of a drug targeting HER2, so it can be used to monitor treatment in real time. When used in a 41-year-old patient with metastatic breast cancer, it already detected more lesions than routinely used 18F-FDG in initial scans, confirming high levels of HER2 in the areas examined.

- We are confident that the data collected from these PET scans will allow us to tailor treatment plans for each patient individually, based on the current status of their HER2 receptors. With this knowledge, we want to design more effective personalized medicine strategies, thereby improving treatment outcomes," explains Prof. Kramer-Marek. - Our goal is also to avoid giving patients therapies that will not be effective in them, and are often associated with significant toxicity. In this way, we want to spare them unnecessary side effects," he adds.

Affibody AB, which supplied the Affibody molecule for non-invasive HER2 imaging with PET radioimmunoassay, is also pleased with the preliminary results of a pilot clinical trial being conducted at the National Cancer Institute in Gliwice. - We are excited to collaborate with leading experts at the Maria Sklodowska-Curie National Cancer Institute in Gliwice to improve precision medicine through molecular imaging," says Fredrik Frejd, Affibody AM's scientific director. - The use of the Affibody ABY-025 molecule will enable improved clinical outcomes, providing patients and the treating physician with more complete information about the disease. We look forward to further collaboration with our colleagues at the Maria Sklodowska-Curie Institute of Oncology in Gliwice as the study progresses, he adds.

source: press release