Understanding the Latest Prostate Cancer Drugs

When Is Prostate Cancer Medication Used?

The preferred treatment options for prostate cancer depend on factors including the cancer’s stage. In the early stages of prostate cancer, surgery often can remove the whole tumor or radiation therapy may be able to eliminate it. These approaches can quickly eradicate the cancer with minimal risk of recurrence. However, if prostate cancer has reached an advanced stage, and has spread beyond the prostate and immediately surrounding tissues, surgical removal is not an effective approach.

Prostate cancer drugs are prescribed for metastatic castration-resistant prostate cancer (mCRPC). This term refers to cancer that has spread beyond the prostate and that is not responding to drugs given to lower levels of androgens, the male sex hormones that drive prostate cancer, particularly in its early stages. While surgery may still be used to remove the primary tumor, it cannot address cancer that has spread elsewhere in the body. Drugs are systemic, meaning that they spread through the bloodstream or lymphatic system to reach the entire body. This makes them effective at controlling metastatic cancer.

Chemotherapy

Chemotherapy, or chemo, is one of the most commonly employed and well-established drug treatments for cancer. It works by attacking cells that are in the process of dividing. Because cancer cells divide much more rapidly than normal cells, chemo drugs are highly toxic to them. However, chemotherapy can also damage other fast-growing cells in the body, causing hair loss, and can have other side effects including fatigue, nausea and vomiting, and reduced immune function.

The most common types of chemotherapy administered for prostate cancer are:

• Docetaxel
• Cabazitaxel
• Mitoxantrone

Hormone Therapy

Hormone therapy is another common approach to prostate cancer treatment. As noted above, prostate cancers use androgens, or male sex hormones, to grow. Hormone therapies work by lowering androgen levels or stopping the cancer from absorbing hormones. By denying cancer the materials it needs to grow, hormone therapy slows its growth and may even shrink the tumor. Types of hormone therapy used for prostate cancer include:

• Luteinizing hormone-releasing hormone (LHRH) agonists
• LHRH antagonists
• Abiraterone
• Androgen receptor pathway inhibitors, including enzalutamide, apalutamide, and darolutamide

Although hormone therapy can slow cancer, it cannot cure the cancer by itself. For this reason, it is most often prescribed alongside other treatment types. It may be used before or during radiation therapy for early-stage prostate cancer, especially if the cancer is at high risk of recurrence. It may also be used to control late-stage metastatic prostate cancer.

Radiopharmaceutical Therapy

Radiopharmaceuticals are a unique treatment type that combines drug therapies with radiation therapy. They are drugs that contain radioactive elements. The drug travels through the bloodstream to find and attach to cancer cells, where it gives off radiation to kill the cancer. Types of radiopharmaceutical drugs are differentiated by how they target cancer cells:

• PSMA: Lu-PSMA-617 is a radiopharmaceutical that attaches itself to prostate-specific membrane antigens (PSMAs), a type of protein that is found in large quantities on prostate cancer cells.
• Bones: Radium-223, Strontium-89, and Samarium-153 are radiopharmaceuticals designed to settle into the bones, making them effective against prostate cancer that has spread there.

Both types of radiopharmaceuticals are used for Stage IV metastatic prostate cancer.

Immunotherapy and Vaccines

Immunotherapy is a cutting-edge development in prostate cancer treatment. This approach works by teaching the patient’s immune system to recognize and attack cancer cells.

Cancer Vaccine

Sipuleucel-T is a cancer vaccine that is formulated specifically for each patient. White blood cells are removed from the patient’s body over the course of a few hours. The cells are sent to a laboratory, where they are mixed with a prostate cancer protein called prostatic acid phosphatase (PAP). They are then injected back into the patient, where they use the PAP protein to identify and destroy cancer.

Checkpoint Inhibitors

The immune system uses checkpoint proteins to identify normal cells. When immune cells detect a checkpoint protein, they know not to attack the cell. However, some cancer cells manufacture their own checkpoint proteins to protect themselves against attacks. Checkpoint inhibitor drugs like pembrolizumab target these proteins to eliminate the cancer’s defenses.

Targeted Therapy

Targeted therapy is a breakthrough area of cancer research. These drugs attack specific features that make cancer cells different from normal cells. They sometimes work when chemotherapy and hormone therapy do not, and they often have fewer or different side effects.

The primary type of targeted therapy used for prostate cancer is PARP inhibitors. PARP (poly (ADP-ribose) polymerase) enzymes are proteins that help repair damaged DNA. Other proteins assist with the same function but are frequently impacted by cancerous gene mutations. For cancers with these mutations, PARP inhibitors can halt DNA repair. In time, this leads to the death of the cell. Types of PARP inhibitors include:

• Rucaparib
• Olaparib
• Talazoparib
• Niraparib plus abiraterone acetate

PARP inhibitors are typically used alongside chemotherapy or hormone therapy for the best effect. They are not an option for all patients, however. Targeted drug therapies are helpful only if cancer cells have changes in their DNA repair genes. A blood test or prostate cancer biopsy is necessary to determine whether this treatment approach will be effective.

Bisphosphonates and Denosumab

Bisphosphonates and denosumab are two drugs sometimes prescribed to prostate cancer patients, although they do not treat prostate cancer itself. Rather, they work to protect bone integrity, which can be adversely affected by some of the hormone therapies used to treat prostate cancer or by prostate cancer metastases, which tend to develop in bone. 

Bisphosphonates

Bisphosphonates like zoledronic acid work by slowing down cells called osteoclasts. These cells are responsible for breaking down the mineral structure of bones to keep them healthy. When prostate cancer spreads into the bones, osteoclasts can become overactive, causing pain and bone weakness. Bisphosphonates help to relieve pain and prevent fractures.

Denosumab

Similar to bisphosphonates, denosumab also blocks osteoclasts. It uses a different method, however, making it sometimes effective after bisphosphonates stop working. Denosumab is used for similar applications, helping to minimize pain and fracture risks.

Find Comprehensive Prostate Cancer Care Near You in NJ, CT, MA, and the Washington, D.C., Area

Prostate cancer medications are delivering better results than ever before as clinical trials provide information on the ways to use them most effectively. Patients interested in learning more can reach out to Regional Cancer Care Associates (RCCA). We are one of the largest cancer treatment networks in the country, serving patients at more than 20 locations near you in New Jersey, Connecticut, Massachusetts, and the Washington, D.C., area. Contact us today to schedule a consultation.