Results of the ENPAC Trial Shows Promise in Recurrent Endometroid Cancer

Shannon N. Westin, MD, MPH, discusses the promising results of the ENPAC trial that showed the effectiveness of adding enzalutamide to standard of care chemotherapy for patients with recurrent endometriod cancer.

Shannon N. Westin, MD, MPH, an associate professor, Department of Gynecologic Oncology and Reproductive Medicine, Division of Surgery at the University of Texas MD Anderson Cancer Center, discusses the design and results of the phase 2 ENPAC trial (NCT02684227) that showed the promise of enzalutamide (Xtandi) plus carboplatin and paclitaxel in patients with advanced or recurrent endometrioid endometrial cancer.

The results of the study showed that of the 35 patients who were evaluable for response had a response rate of 71% (95% CI, 54%-85%), with 83% (95% CI, 66%-92%) of patients remaining progression-free for at least 6 months. Moreover, there was a median overall survival of 32 months and median progression-free survival of 14 months.

Westin discusses these results as well as the design of the trial that focused on patients with endometroid endometrial cancer as this patient population showed initial promise when combining the 3 drugs together.


0:06 | We chose enzalutamide because of protein data that we had explored, that demonstrated high levels of androgen receptor expression in [patients with] endometrial cancer, specifically those with endometrioid type. Those levels were higher than what we see with prostate cancer, and obviously prostate cancer is where these androgen receptor antagonists have really been utilized. So, we were intrigued by our findings that [results in patients with] endometrial cancer looked so similar, so what we planned was to combine the enzalutamide with that standard of care paclitaxel and carboplatin.

0:41 | These 3 drugs had never been combined previously, so we did have a safety lead in where we demonstrated that the combination was tolerable, and we did not see any dose limiting toxicities. The way we designed the second half of the study, is we had a 4 week lead in of just the enzalutamide, and that was predominantly for translational endpoints, so we could see pre and post treatment biopsies around that enzalutamide and understand what the drug did to the tumor and how the tumor responded to that single agent treatment. Then patients were transitioned on to the 3-drug combination.

1:22 | We were very excited to see high response rates were response rates approached 75%, so almost all patients had a reduction, we only had just a few patients with progression of disease. And importantly, progression free survival was about 14 months and so we were very excited about the results of this single arm study.