Androgen deprivation therapy (ADT) has often been utilized as the standard of care for the treatment of metastatic hormone-sensitive prostate cancer (mHSPC), but in many cases, the disease progresses to castration-resistant prostate cancer within 1 to 3 years. Several studies have tested the use of second-generation androgen receptor axis-targeted inhibitors (ARATs) in patients with mHSPC to determine if the early use of ARATs in patients may improve outcomes, including overall survival and progression-free survival.
Researchers from Japan created a multicenter retrospective study that examined untreated patients with mHSPC who were part of various trials, including LATITUDE, STAMPEDE, ENZAMET, and ARCHES to determine similar characteristics among various ARAT treatments, as well as how changes in the usage of ARATs occurred over time.
The study included 581 patients with newly diagnosed mHSPC who received first-line hormone therapy between February 2018 and December 2021. Biochemical recurrence-free survival (BRFS) was used to compare efficacy among patient groups for the different ARAT treatments that were studied: apalutamide, enzalutamide, abiraterone acetate, and apalutamide plus enzalutamide. A multivariate analysis was also utilized to find predictive factors of biochemical recurrence (BCR).
No significant difference in BRFS was found in patients treated with apalutamide or enzalutamide (P=.490) compared with abiraterone or apalutamide plus enzalutamide (P=.906). A neutrophil-to-lymphocyte ratio (NLR) of 2.76 or greater and a prostate-specific antigen (PSA) level of .550 ng/mL or greater were independent predictors of BCR. No significant differences were found in patient characteristics or BRFS in patients with mHSPC receiving different ARATs as first-line treatment.
In 2020, the Adelphi Prostate Cancer Disease Specific Programme collected information on patients with mHSPC in the United States, Europe, and Japan to determine which ARAT agents were commonly used as first-line treatments. Among the overall population, ADT was used as a first-line therapy in 47.2% of patients with mHSPC, while ARATs were used in 28.9% of patients. When investigating the transition of treatment agents after 2020, data showed that apalutamide and enzalutamide were administered in 25% and 10.5% of cases, respectively, and abiraterone was used in 28.2% of cases. In Japan, ARATs have been used in many patients with mHSPC, and in a variety of therapeutic modalities, since 2020.
The study results show a trend toward the use of ARATs for the treatment of mHSPC. NLR and PSA may also serve as prognostic factors following the first-line treatment of patients with mHSPC.