Treatment of advanced prostate cancer through the use of anti-androgens: Understanding their mechanism

Treatment options for advanced prostate cancer: An explanation of anti-androgen drugs

Second-Generation Anti-Androgens Offer New Hope in Prostate Cancer Treatment

Second-generation anti-androgens are proving to be a significant advancement in the treatment of prostate cancer, particularly for cases that are not responding to other hormone therapies. These medications work by more effectively lowering levels of androgens in the body and preventing androgens from supporting the growth of prostate cancer cells.

The main differences between first-generation and second-generation anti-androgens lie in their mechanism of action, efficacy, and clinical outcomes.

First-generation anti-androgens, such as bicalutamide, primarily work by competitively inhibiting the androgen receptor (AR) at the ligand-binding domain. However, they are less potent and in some cases may have partial agonist effects, which can limit their effectiveness, especially in advanced stages of prostate cancer.

Second-generation anti-androgens, such as enzalutamide, apalutamide, and darolutamide, offer several advancements. They bind more strongly and specifically to the AR ligand-binding domain, inhibit AR translocation into the nucleus, and prevent recruitment of co-activators necessary for gene transcription. This results in a more complete blockade of androgen signaling compared to first-generation agents.

Clinically, second-generation agents have demonstrated improved oncological outcomes, including longer progression-free survival and overall survival in both metastatic hormone-sensitive and castration-resistant prostate cancer, whereas first-generation drugs show less robust benefits.

In summary:

| Feature | First-Generation Anti-Androgens | Second-Generation Anti-Androgens | |----------------------------|----------------------------------------------------------|-----------------------------------------------------------| | Binding to AR | Competitive inhibition at ligand-binding domain | Stronger binding plus inhibition of AR nuclear translocation | | Mechanism | Partial antagonist with possible agonist effects | Pure antagonists blocking multiple AR activation steps | | Clinical efficacy | Moderate, less effective in advanced disease | Greater efficacy, improves progression-free and overall survival | | Examples | Bicalutamide | Enzalutamide, Apalutamide, Darolutamide |

These distinctions explain why second-generation anti-androgens are now preferred for advanced and metastatic prostate cancer treatment. Newer anti-androgens such as enzalutamide and apalutamide may be an important part of treating castration-resistant prostate cancer (CRPC), which is prostate cancer that continues to grow despite low testosterone levels.

Enzalutamide improves overall survival in metastatic CRPC before and after treatment with chemotherapy, and also improves metastatic-free survival in nonmetastatic CRPC. First-generation anti-androgens for treating prostate cancer include flutamide, bicalutamide, and nilutamide.

Doctors may prescribe anti-androgens alongside other treatments in advanced stages of prostate cancer or if other treatments are no longer effective. The side effects of second-generation anti-androgens may include diarrhea, fatigue, rash, worsening of hot flashes, effects on the nervous system such as dizziness or seizures (rare), heart problems, increased risk of falls, and fewer side effects relating to the central nervous system for darolutamide due to its ability to cross the blood-brain barrier.

Researchers suggest that a combination of androgen deprivation therapy (ADT) and anti-androgen treatment may improve the effectiveness of treatment. It's important to note that anti-androgens are just one of many treatment options for prostate cancer, including other types of hormone therapies, chemotherapy, external radiation therapy, bisphosphonates, alpha emitter radiation therapy, watchful waiting or active surveillance, transurethral resection of the prostate (TURP), clinical trials with radical prostatectomy and orchiectomy, and clinical trials with new treatment options such as cryosurgery and high-energy sound waves.

Androgens and androgen receptors allow prostate cancer cells to grow. Metastasis is the process of cancer cells spreading throughout the body. Anti-androgens bind to androgen receptors on prostate cancer cells to prevent their growth.

In conclusion, second-generation anti-androgons are a promising development in the treatment of prostate cancer, offering greater efficacy and improved clinical outcomes compared to first-generation agents. They are an essential tool in the fight against this disease, particularly in advanced stages and cases resistant to other hormone therapies. As always, it's crucial to discuss treatment options with a healthcare professional to determine the best course of action.

References: [1] Cancer Research UK [2] American Cancer Society [5] Mayo Clinic