A landmark case report suggested a potential breakthrough in the treatment of an aggressive type of prostate cancer, according to a recent study published by Lap et al in the Annals of Internal Medicine.
The antibody-drug conjugate fam-trastuzumab deruxtecan-nxki (T-DXd) was approved by the U.S. Food and Drug Administration for the treatment of a variety of HER2-expressing solid tumors, including breast cancer. However, the effects of the drug have not been examined in prostate cancer.
Case Report Methods and Findings
In the case report, researchers assigned a 60-year-old male patient diagnosed with stage IV metastatic prostate cancer to receive treatment with T-DXd. The patient initially didn’t respond to multiple lines of therapy and experienced persistent tumor progression. The researchers subsequently tested the patient for HER2 by immunohistochemistry, which came back positive. As a result, the patient was treated off label in February 2024 with T-DXd.
Following four cycles of T-DXd, the patient demonstrated a 57% overall reduction in tumor volume, including in the brain. His condition improved significantly, defying earlier prognoses that suggested a transition to hospice care because of a lack of treatment options. As of November 2024, the patient was clinically doing well and he has received treatment for 9 months. The prior three lines of treatment for the patient’s advanced prostate cancer worked only 3 to 4 months each.
Conclusions
“This case highlights the promising potential of T-DXd in treating [patients with] prostate cancer, particularly … aggressive [types of disease],” emphasized senior study author Maneesh Jain, MD, MS, an oncologist at the George Washington University School of Medicine and Health Sciences and an attending physician in the Section of Hematology & Medical Oncology at the Washington, DC, Veterans Affairs Medical Center. “It also underscores the importance of routine HER2-expression testing in advanced prostate cancer, which could help identify more patients who might benefit from targeted therapies like T-DXd.”
Disclosure: The research in this study was funded by the Prostate Cancer Foundation. For full disclosures of the study authors, visit acpjournals.org.
