RT Journal Article
SR Electronic
T1 <sup>18</sup>F-Fluoroestradiol PET Imaging in a Phase II Trial of Vorinostat to Restore Endocrine Sensitivity in ER+/HER2− Metastatic Breast Cancer
JF Journal of Nuclear Medicine
JO J Nucl Med
FD Society of Nuclear Medicine
SP 184
OP 190
DO 10.2967/jnumed.120.244459
VO 62
IS 2
A1 Lanell M. Peterson
A1 Brenda F. Kurland
A1 Fengting Yan
A1 Alena Novakova- Jiresova
A1 Vijayakrishna K. Gadi
A1 Jennifer M. Specht
A1 Julie R. Gralow
A1 Erin K. Schubert
A1 Jeanne M. Link
A1 Kenneth A. Krohn
A1 Janet F. Eary
A1 David A. Mankoff
A1 Hannah M. Linden
YR 2021
UL http://jnm.snmjournals.org/content/62/2/184.abstract
AB Histone deacetylase inhibitors (HDACIs) may overcome endocrine resistance in estrogen receptor–positive (ER+) metastatic breast cancer. We tested whether 18F-fluoroestradiol PET imaging would elucidate the pharmacodynamics of combination HDACIs and endocrine therapy. Methods: Patients with ER+/human epidermal growth factor receptor 2 (HER2)–negative metastatic breast cancer with prior clinical benefit from endocrine therapy but later progression on aromatase inhibitor (AI) therapy were given vorinostat (400 mg daily) sequentially or simultaneously with AI. 18F-fluoroestradiol PET and 18F-FDG PET scans were performed at baseline, week 2, and week 8. Results: Eight patients were treated sequentially, and then 15 simultaneously. Eight patients had stable disease at week 8, and 6 of these 8 patients had more than 6 mo of stable disease. Higher baseline 18F-fluoroestradiol uptake was associated with longer progression-free survival. 18F-fluoroestradiol uptake did not systematically increase with vorinostat exposure, indicating no change in regional ER estradiol binding, and 18F-FDG uptake did not show a significant decrease, as would have been expected with tumor regression. Conclusion: Simultaneous HDACIs and AI dosing in patients with cancer resistant to AI alone showed clinical benefit (6 or more months without progression) in 4 of 10 evaluable patients. Higher 18F-fluoroestradiol PET uptake identified patients likely to benefit from combination therapy, but vorinostat did not change ER expression at the level of detection of 18F-fluoroestradiol PET.