Use of Apalutamide in Men With Lower-Risk Prostate Cancer on Active Surveillance
Posted: Thursday, January 21, 2021
At the 2020 Annual Meeting of the Society of Urologic Oncology (SUO), Michael T. Schweizer, MD, of Seattle Cancer Care Alliance, and colleagues presented their research on the use of the androgen receptor–signaling inhibitor apalutamide and its ability to downstage low-grade tumors in men enrolled on active surveillance. Active surveillance has been an effective regimen for men with lower-risk prostate cancer, but patients often undergo radiation therapy or prostatectomy regardless. This study was featured among the Best of Prostate Cancer at the SUO meeting, and the investigators determined apalutamide to be safe and well tolerated in these patients.
This open-label, phase II study enrolled 23 patients with no more than low- to intermediate-risk prostate cancer followed by active surveillance. In the absence of medical or surgical castration, apalutamide was administered orally for 90 days at 240 mg daily. Low to intermediate risk was defined by clinical stage T1c disease, Gleason 3 plus 4 (up to 50% of one core detected by biopsy), Gleason 3 plus 3 (disease in all other cores), and/or a prostate-specific antigen (PSA) level of less than 15 ng/mL.
Of the total, 22 participants completed the 90 days of apalutamide with a post-treatment biopsy. Due to the SARS-CoV-2 pandemic, one patient dropped out before biopsy to reduce his risk of exposure to the coronavirus. Gleason grade group 1 disease affected 65% of men, whereas the rest of the cohort experienced Gleason grade group 2 disease. Per the National Comprehensive Cancer Network criteria, 13% of individuals had very low–risk cancer.
There was no evidence of residual cancer in 59% of post-treatment biopsies and 37% of secondary biopsies 1 year after treatment. According to the study authors, all patients had a greater than 50% decline in PSA levels, and any side effects from androgen receptor–signaling inhibition quickly subsided after study completion. Grade 3 hypertension and grade 3 rash affected one patient each, but the men could continue treatment on a reduced dose.
Disclosure: No disclosure information for the study authors was provided.
