Real-World Survival Analysis of Apalutamide vs Enzalutamide in mCSPC

Neal Shore, MD, FACS, United States chief medical officer of surgery and oncology, GenesisCare USA, and director of the Carolina Urologic Research Center, discusses the background of a study aimed to investigate the real-world survival outcomes of men with metastatic castration-sensitive prostate cancer (mCSPC) who were treated with either apalutamide (Erleada) or enzalutamide (Xtandi) in the United States.

Researchers on the trial used data from the Flatiron Metastatic Prostate Cancer Core Registry Electronic DataMart between January 1, 2013, and May 31, 2023. Patients were categorized into 2 cohorts based on the initiation of apalutamide or enzalutamide after December 16, 2019, and 234 patients were included in the study and treated with apalutamide while 527 patients were treated with enzalutamide.

The median time on treatment for apalutamide was 10.9 months over a median observation period of 13.3 months. For enzalutamide, the median time on treatment was 11.1 months over a median observation period of 14.8 months. By 24 months post-initiation, a higher proportion of patients in the apalutamide cohort survived compared with the enzalutamide cohort (85.4% vs 73.9%), and unadjusted analysis showed a statistically significant difference in survival rates between the 2 groups.

Transcription:

0:09 | Sometimes, randomized controlled trials are hard to accomplish there. We always like to do those, especially prospectively. But given the fact that these are both approved and highly effective drugs, I think it is interesting from a clinician standpoint, whether you are in the community or academic, to see what our real-world experience is and what do the data and registry large sets tell us?

0:39 | This was a retrospective, longitudinal cohort of patients, largely coming from the Flatiron registry, which is an electronic dataset and patient charts interrogated from January 1 2013, through the end of May 31, 2023. Patients had to have had a chart confirm metastasis, without any castration resistance findings. We had 2 cohorts based on the earliest initiation of either apalutamide or enzalutamide on or after the index date of December 2019. Patient's had to have had greater than a year, 12 months, of clinical data prior to the index, and were followed from the index date until the earliest of 24 months post the index and the end of clinical activity or the end of data availability.

1:48 | When we looked at important data metrics such as the date of death,

their Social Security death index, and other confirmed sources. We took an analysis called an intention-to-treat approach. A Kaplan Meier analysis used to describe the proportion of patients surviving 2 years, 24 months, post-index. We also used an unadjusted Cox Proportional Hazards model to describe any differences in survival rates between patients who are either initiated with apalutamide or enzalutamide.

REFERENCE

Bilen MA, Khilfeh I, Rossi C, et al. Real-world Survival of Men With Metastatic Castration-sensitive Prostate Cancer (mCSPC) Initiated on Apalutamide (APA) or Enzalutamide (ENZ) in an Oncology Database: ROME Study. J Clin Oncol. 2024;42(Suppl 4):58. doi:10.1200/JCO.2024.42.4_suppl.58