Use of 64Cu-DOTA-Trastuzumab PET to Predict Response and Outcome of Patients Receiving Trastuzumab Emtansine for Metastatic Breast Cancer: A Pilot Study

• Published in: The Journal of nuclear medicine (1978) Vol. 63; no. 8; pp. 1145 - 1148
• Main Authors: Mortimer, Joanne E, Bading, James R, Frankel, Paul H, Carroll, Mary I, Yuan, Yuan, Park, Jinha M, Tumyan, Lusine, Gidwaney, Nikita, Poku, Erasmus K, Shively, John E, Colcher, David M
• Format: Journal Article
• Language: English
• Published: New York Society of Nuclear Medicine 01.08.2022
• Subjects: Antibodies; Breast cancer; Brief Communication; Computed tomography; Epidermal growth factor; Growth factors; Metastases; Monoclonal antibodies; Patients; Positron emission; Positron emission tomography; Targeted cancer therapy; Tomography; Trastuzumab; Tumors
• ISSN: 0161-5505; 1535-5667
• DOI: 10.2967/jnumed.121.262940

We hypothesized that functional imaging with 64Cu-DOTA-trastuzumab PET/CT would predict the response to the antibody–drug conjugate trastuzumab–emtansine (T-DM1). Methods: Ten women with metastatic human epidermal growth factor receptor 2–positive breast cancer underwent 18F-FDG PET/CT and 64Cu-DOTA-trastuzumab PET/CT on days 1 and 2 before treatment with T-DM1. Results: T-DM1–responsive patients had higher uptake than nonresponsive patients. Day 1 minimum SUVmax (5.6 vs. 2.8, P < 0.02), day 2 minimum SUVmax (8.1 vs. 3.2, P < 0.01), and day 2 average SUVmax (8.5 vs. 5.4, P < 0.05) for 64Cu-DOTA-trastuzumab all favored responding patients. Tumor-level response suggested threshold dependence on SUVmax. Patients with a day 2 minimum SUVmax above versus below the threshold had a median time to treatment failure of 28 mo versus 2 mo (P < 0.02). Conclusion: Measurement of trastuzumab uptake in tumors via PET/CT is promising for identifying patients with metastatic breast cancer who will benefit from T-DM1.