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ASCO GU 2022

ASCO GU 2022: PSA Outcomes in Black and White Chemotherapy-Naïve Prostate Cancer Patients Treated with Enzalutamide

(UroToday.com) The 2022 GU ASCO Annual meeting included a prostate cancer session featuring work from Dr. Alicia Morgans and colleagues presenting results of their study assessing PSA outcomes in black and white chemotherapy-naïve prostate cancer patients treated with enzalutamide. Population-level data suggest that black men are more likely to be diagnosed and die from prostate cancer. In juxtaposition, across multiple treatments for advanced prostate cancer, studies suggest black men have better survival than white men, including with novel hormone therapies such as enzalutamide. Whether improved survival is driven by better clinical response is unknown, as data on racial differences in treatment response for enzalutamide are limited. As such, this study assessed real-world PSA outcomes (response and progression) of enzalutamide-treated black vs white chemotherapy-naive prostate cancer patients in the United States.


This study was a retrospective cohort analysis of prostate cancer patients who initiated enzalutamide in the IntrinsiQ Specialty Solutions urology electronic medical records database from September 1, 2014 to February 28, 2018. The index date was the first prescription for enzalutamide and the follow-up period was from the index date to the earliest of date of death or end of data (defined as last visit date or June 30, 2018, whichever came first). Patients with evidence of prior chemotherapy and/or abiraterone were excluded. Baseline characteristics, PSA response (PSA decline ≥50% or ≥90%), and clinical progression-free survival (cPFS) were assessed by race. cPFS was defined as the earliest of the following:

  • ≥25% increase or an absolute increase of ≥2 ng/mL above the baseline (if all post-baseline PSA values were higher than baseline) or above the nadir
  • Change to second-line treatment
  • All-cause death
Kaplan-Meier and Cox models adjusting for baseline characteristics were used to estimate PSA response and cPFS.

The study included 214 black and 1,332 white chemotherapy-naive prostate cancer patients. Black patients were younger and had a higher baseline median PSA than white patients. Charlson Comorbidity Index, median duration of therapy, follow-up time, and number of post-index PSA tests were similar between races. The median treatment duration and PSA response were as follows:

ASCO_GU_Morgans.png


In adjusted analyses, the probability of patients achieving ≥50% PSA decline was similar:

Morgans.png


whereas a numerically higher trend was observed for ≥90% PSA decline in black patients:

Alicia_Morgans.png


In addition, black men had significantly better cPFS (HR 0.82; 95% CI 0.68, 0.98; p=0.03):

ASCO_GU_2022_Morgans.png


Dr. Morgans concluded with the following take home messages for this study assessing PSA outcomes in black and white chemotherapy-naïve prostate cancer patients treated with enzalutamide:

  • This real-world study found a similar PSA response in black and white chemotherapy-naive prostate cancer patients treated with enzalutamide
  • However, black patients may have better cPFS than white patients
  • There was no evidence of differential follow-up or surveillance in treatment duration and number of post-index PSA tests between black and white patients
  • This study reinforces the effectiveness of enzalutamide for the treatment of chemotherapy-naïve patients with prostate cancer, irrespective of race
  • Outcomes of this study are consistent with other real-world studies that assessed treatment outcomes in black and white patients with prostate cancer treated with novel hormonal therapies

Presented by: Alicia K. Morgans, MD, MPH, Dana-Farber Cancer Institute, Boston, MA

Co-Authors: Agnes Hong, Sharanya Murty, Nader N. El-Chaar, Krishnan Ramaswamy, Anna D. Coutinho, David Nimke, Stephen J. Freedland

Affiliations: Astellas Pharma Inc., Northbrook, IL, Xcenda, Carrollton, TX, Pfizer Inc., New York, NY, Center for Integrated Research in Cancer and Lifestyle, Cedars-Sinai Medical Center, Los Angeles, CA

Written by: Zachary Klaassen, MD, MSc – Urologic Oncologist, Assistant Professor of Urology, Georgia Cancer Center, Augusta University/Medical College of Georgia, @zklaassen_md on Twitter during the 2022 Genitourinary (GU) American Society of Clinical Oncology (ASCO) Annual Meeting, San Francisco, Thurs, Feb 17 – Sat, Feb 19, 2022.