The IMAAGEN Trial
David Crawford, MD, is the Distinguished Endowed Professor of Surgery, Urology, and Radiation Oncology, and head of the Section of Urologic Oncology at the University of Colorado Anschutz Medical Campus in Aurora, Colorado. He also serves as the Practice Director for the Urologic Oncology clinic. He was the lead author on the report from the Prostate Cancer Radiographic Assessments for Detection of Advanced Recurrence (RADAR) Group published online in Urology. He presented updated results of the IMAAGEN trial at the WSAUA 90th Annual Meeting in Maui, Hawaii, in October.
What are the primary takeaway points from your presentation at the WSAUA meeting on preliminary results of the IMAAGEN trial?
Dr. Crawford: The data presented in Maui were updated from those presented during the ASCO meeting in June. The two primary takeaways from the results to date are that 37% of men we think do not have metastases do; the second is that abiraterone acetate is very effective and well tolerated in the population of patients with non-metastatic castration-resistant prostate cancer.
What were the end points of the IMAAGEN trial?
Dr. Crawford: The primary end point was the proportion of patients with a ≥50% reduction in PSA during cycles 1 through 6. Secondary end points included testosterone levels, safety, time to PSA progression, and time to radiographic disease progression.
What are the results to date?
Dr. Crawford: By the end of 6 treatment cycles, data were available for 122 of the 131 patients enrolled. Of the 122, 106 had a ≥50% reduction in PSA and 73 had a ≥90% reduction. None of the patients required an increase in the prednisone dose to >5 mg for management of symptoms of mineralocorticoid excess.
At baseline, median testosterone level was 10.56 ng/mL; at the end of the 6 cycles, median testosterone level was 0.38 ng/mL.
What are the differences between the patient population in this trial and those in the COU-AA-302 trial of Zytiga® in men with metastatic prostate cancer?
Dr. Crawford: Patients in the IMAGGEN trial were much healthier than those in the COU-AA-302 trial and their disease was at a much earlier stage.
What is the planned timing for the third phase of the evaluation of Zytiga® in men with non-metastatic CRPC?
Dr. Crawford: The data will be reviewed in December.