Description
ARN-509 is a selective and competitive androgen receptor inhibitor with IC50 of 16 nM in a cell-free assay, useful for prostate cancer treatment. Phase 3.
In vitro
ARN-509 (< 10 μM) inhibits androgen-mediated induction or repression of mRNA expression levels for 13 endogenous genes including PSA and TMPRSS2 in the LNCaP/AR prostate cancer cell line. ARN-509 (< 10 μM) inhibits the proliferative effect of R1881 (30 pM) in the LNCaP/AR prostate cancer cell line. ARN-509 (10 μM) impairs AR nuclear localization and thus reduces the concentration of AR available to bind androgen response elements (ARE) in LNCaP cells expressing AR-EYFP. ARN-509 (10 μM) is able to effectively compete with R1881 (1 nM) and prevent AR from binding to promoter regions. ARN-509 inhibits R1881-induced VP16-AR–mediated transcription with IC50 of 0.2 μM in Hep-G2 cells expressing a VP16-AR fusion protein and an ARE-driven luciferase reporter.
In vivo
ARN-509 (10 mg/kg/d, oral) inhibits tumor growth with decreased proliferative index and increased apoptotic rate in castrate male immunodeficient mice harboring LNCaP/AR-luc xenograft tumors. ARN-509 dose dependently inhibits tumor growth with highest efficacy at dose of 30 mg/kg/day in castrate male immunodeficient mice harboring LNCaP/AR-luc xenograft tumors. ARN-509 dosed at 10 mg/kg/d for 28 days results in a 3-fold reduction in prostates weight associated with lacking glandular secretory activity and 1.7-fold reduction in epididymis weight in adult male dogs. ARN-509 (10 mg/kg/d, oral) inhibits cell proliferation of prostate tissues in adult male dogs. ARN-509 is safe and well tolerated in 24 patients with metastatic CRPC who has progressed on prior treatments and peak plasma concentrations occurred 2 to 3 hours after administration. ARN-509 results in durable PSA declines at doses ranging from 30 to 300 mg in patients with metastatic CRPC. ARN-509 shows powerful anti-cancer activity and induces durable remissions long after therapy completion in castrate resistant prostate cancer mouse models.
Uses
Apalutamide is a second-generation antiandrogen used in the treatment of prostate cancer. It is a potent antagonist of androgen receptor with IC50 value of 16 nM. Binds androgen receptors, thereby inhibiting nuclear translocation, DNA binding and transcriptional activation. ARN-509 has therapeutic applications in non-metastatic, castration-resistant prostate cancer.
Pharmaceutical Applications
Apalutamide, also known as ARN-509, is used to treat certain types of castration-resistant prostate cancer or prostate cancer that has not spread to other parts of the body, but has not been helped by other medical treatments. Apalutamide is in a class of medications called androgen receptor inhibitors. It works by blocking the effects of androgen to stop the growth and spread of cancer cells.
On September 17, 2019, the Food and Drug Administration approved apalutamide (ERLEADA, Janssen Biotech, Inc) for patients with metastatic castration-sensitive prostate cancer (mCSPC). Apalutamide was initially approved in 2018 for patients with non-metastatic castration-resistant prostate cancer.
Mechanism of action
Apalutamide, also known as ARN-509 and JNJ-56021927 , is an androgen receptor antagonist with potential antineoplastic activity. ARN-509 binds to AR in target tissues thereby preventing androgen-induced receptor activation and facilitating the formation of inactive complexes that cannot be translocated to the nucleus. This prevents binding to and transcription of AR-responsive genes. This ultimately inhibits the expression of genes that regulate prostate cancer cell proliferation and may lead to an inhibition of cell growth in AR-expressing tumor cells.
