All about FDA-approved prostate cancer vaccine: Sipuleucel-T (Provenge) 

Key takeaways: 

• Sipuleucel-T (Provenge) is the first prostate cancer vaccine approved by the FDA. They are mostly used for older patients and patients in the last stage of prostate cancer.
• No two persons receive the same Provenge infusion. This means that each vaccine medication is made to be used for one person. Each person's immune cells are collected to produce a vaccine specifically for them. 
• Provenge is a great treatment option if your doctor recommends it for you. It doesn't treat or cure cancer completely. However, it can help prolong the number of months or years a person has to live. 

Cancer is a group of diseases caused by uncontrolled cell growth. A cell becomes cancerous when it undergoes certain gene mutations that cause it to grow abnormally. Cancer cells damage a part of the body and spread to other parts to cause more damage. 

Prostate cancer is a cancer of the prostate gland. A prostate is a small gland in the male's reproductive system. It produces some parts of the fluid responsible for reproduction. Prostate cancer mostly affects people who are 65 years or older. People with a family history of the condition, people with gene mutations, and Black people are at a higher risk of developing prostate cancer.

There are different methods of treating prostate cancer, including immunotherapy. During immunotherapy, the immune system is prepared and trained to fight cancer by naturally boosting it and introducing substances into the body that can locate and attack cancer cells.

In this article, we will focus on discussing the first and only FDA-approved vaccine for prostate cancer — Sipuleucel-T (Provenge). We will explain how Provenge is used in immunotherapy to treat prostate cancer. We will also talk about other cancer vaccine treatments that are still in development and other available immunotherapy options.

 What is Sipuleucel-T?

Sipuleucel-T is the only FDA-approved vaccine for prostate cancer. It is often given as a form of immunotherapy and is available in a brand version called Provenge.

Sipuleucel-T is used to treat patients whose prostate cancer has spread to other parts of the body and shows little to no symptoms. Healthcare professionals often opt for it when hormonal therapy has failed to work. 

Sipuleucel-T also treats castration-resistant prostate cancer, which occurs when cancer grows and worsens despite the level of testosterone hormone being low. Cancer is sensitive to the hormone testosterone; it normally grows when testosterone levels are high. But in the case of castration-resistance cancer, the cancer has reached the advanced stage such that it keeps growing even if testosterone levels are low.

 When did the FDA approve Provenge?

The drug development process for Provenge began in the 1980s by a pharmaceutical company, Dendreon's Ltd. Provenge was later approved by the Food and Drug Administration (FDA) on 29th April 2010.

 How does Provenge work?

Provenge boosts and stimulates the immune system to attack and fight cancer cells, which is what immunotherapy is all about. Provenge does not act as a new substance in the body. Rather, it acts as a part of the patient's immune system. 

Provenge targets and attacks the prostatic acid phosphatase (PAP), a tissue antigen produced by prostate cancer cells. Provenge generates PAP-specific T-cells (white blood cells) that recognize the PAP inside the prostate cancer cells and launches an attack on them. 

The generation of these PAP-specific T-cells takes place outside the body through a process called leukapheresis. Once Provenge is administered into the body, they recognize, fight, and kill prostate cancer cells.

 How is Provenge made?

Provenge is tailor-made for each patient. It is manufactured in a step-by-step process.

The patient's blood is run through a machine in a process known as leukapheresis. Leukapheresis separates and collects the white blood cells (the body's immune system cells) from the other blood cells. 

These immune cells are then exposed to a peptide (protein) derived from PAP. This protein will stimulate and direct the immune cells against the cancer cells. 

After this exposure, the doctor reintroduces the activated immune cells into the patient's blood. The patient's immune system is now able to fight prostate cancer.

 How is Provenge given?

Provenge is given through an intravenous route of administration. That means your healthcare provider will administer it through your veins.

The treatment usually takes about one month to administer and is given in three doses - two weeks apart.

That is:

First dose -> Two weeks -> Second dose -> Two weeks -> third dose. 

The doctor administers each dose about three days after they collect the white blood cells. Thirty minutes before administration, your doctor may suggest you take paracetamol or an antihistamine to reduce side effects. 

The administration lasts for about 60 minutes. Your doctor will monitor you before, during, and 30-60 minutes after the administration. This is to ensure that the process goes smoothly. 

If you miss a dose of Provenge, contact your doctor immediately to know how best to handle it. 

 When is Provenge used?

Provenge is used when prostate cancer has advanced to the last stage. This includes when the cancer is metastatic, asymptomatic, or castration-resistant. 

It is used when the patient doesn't respond to other prostate cancer treatments like hormone therapy and chemotherapy. 

Provenge is person-specific; it's tailor-made for an individual. But it may not be the best treatment option for everyone. It is always best to speak with your healthcare team to learn more about the pros and cons of using the prostate cancer vaccine and work with them to determine if it is the best treatment option for you.

 How effective is Provenge?

Sipuleucel-T is effective against asymptomatic or minimally symptomatic metastatic castration-resistant (hormone-refractory) prostate cancer. 

In a study where two groups of cancer patients received sipuleucel-T and a placebo, respectively. The risk of death was reduced by 22% in the group that received the prostate cancer vaccine compared to the group that did not. This indicates that Provenge is effective for treating prostate cancer and can help increase the chances of prostate cancer survival.

However, while Provenge helps patients live several months longer, it does not cure cancer completely.

 Cost of Provenge

As of 2010, the year it was approved, Provenge sold for $93,000 for the full treatment. 

The price of Provenge today depends on the pharmacy you visit, your insurance plan, and your location. 

You can only get Provenge from the manufacturer, Dendreon Pharmaceuticals Ltd. Dendreon also offers financial support for patients to cushion the effect of the high cost of the vaccine. 

 Side effects of Provenge

Like other medications, Provenge is not without side effects. Some of the most common side effects of Provenge include:

• Chills
• Nausea
• Back pain
• Fatigue
• Fever
• Headache
• Joint ache

Provenge infusion can also cause severe complications, such as:

• Dyspnea (shortness of breath) 
• Vertigo (dizziness) 
• Chest pain
• Irregular heartbeats

These side effects may occur shortly after Provenge has been administered to the body. Talk to your doctor if you start to experience any of these reactions.

 Is there a new cancer vaccine in development?

Health experts and researchers have been looking for better treatment solutions for cancer over the years. Aside from sipuleucel-T, scientists are working on developing other cancer vaccines. One such new cancer vaccine that is still in development is PROSTVAC. 

In its phase II study, PROSTVAC prolonged median overall survival in prostate cancer patients by 8.5 months.  That means 50% of the patients were still alive 8.5 months after the onset of the phase II study.

The medication is associated with prolonging the lives of people with an advanced stage of prostate cancer. It is particularly designed for managing metastatic castration-resistant prostate cancer. 

 Other Immunotherapy options for prostate cancer

Like the prostate cancer vaccine, which is a form of immunotherapy, there are other immunotherapy options for patients. 

Remember that immunotherapy strengthens and stimulates the immune system to fight cancer. And unlike other vaccines, cancer vaccines only work when a person has already developed cancer. 

Other Immunotherapy options for treating prostate cancer patients include:

• Immune checkpoint inhibitors
• T-cell transfer therapy
• Monoclonal antibodies
• Immune System Modulators 

 Immune checkpoint inhibitors

These are certain types of medications that are designed to block immune system checkpoints. These checkpoints hide cancer cells to avoid detection by the immune system. By blocking these checkpoints, the immune cells recognize and fight cancer cells.

They include:

• PD-1 Inhibitor drugs like Pembrolizumab (Keytruda) and Nivolumab (Opdivo). 
• PD-L1 Inhibitor drugs like Atezolizumab (Tecentriq) and Avelumab (Bavencio)
• CTLA-4 inhibitor drugs like Ipilimumab (Yervoy) and tremelimumab (Imjuno)
• LAG-3 inhibitor drugs

 T-cell transfer therapy

This is also called adoptive immunotherapy, immune cell therapy, or adoptive cell therapy. This treatment method is designed to boost the body's T-cells to fight off prostate cancer. During this treatment, the healthcare professional will take out some immune cells from one of the malignant tumors in the prostate.

The most active immune cells are then selected and treated with genetically-modified proteins that attack specific tumors. Oncology scientists will grow more of the immune cells in the lab, after which they will be removed and administered into the patient's body through the veins.[6]

Like cancer vaccines, T-cell transfer therapy does not treat cancer completely. It, however, improves the overall survival and quality of life for people with cancer. 

 Monoclonal antibodies

Also called therapeutic antibodies, these medications are proteins designed in the laboratory to stick to certain parts of cancer cells. They mark cancer cells so the immune system can see and attack them.

There are 4 ways to make these antibodies, and their names are based on what they are made of:

• Murine
• Chimeric
• Humanized
• Human

Monoclonal antibodies have shown limited success in the management of prostate cancer. The chemical and physical barriers around some cancer cells make them inaccessible to these antibodies. Hence, the immune system cannot attack such cancer cells.

 Immune System Modulators

These medications target the pathways that treat cancers. They work on the immune system by turning up or turning down some proteins. They affect the whole or specific parts of the immune system. 

They include Thalidomide, lenalidomide, and Imiquimod.

Lenalidomide reduces the prostate-specific antigen (PSA) level in prostate cancer patients. PSA indicates the presence of cancer cells in the prostate. Thalidomide suppresses pain and inflammation in prostate cancer patients. Results from pre-clinical trials showed that Imiquimod reduced tumor growth and increased cell death in mice.

The drug development process is still ongoing to properly establish their efficacy and safety. 

 Wrap up

Provenge is the first and only FDA-approved vaccine for treating prostate cancer. However, unlike vaccines for viruses that are administered to protect against diseases, cancer vaccines, such as Provenge, are designed to help the immune system fight against an already existing disease.

Provenge is important in managing metastatic castration-resistant prostate cancer, an advanced-stage cancer. This vaccine has some possible side effects. But, in most cases, the benefits outweigh the risks.

Communicating with your doctor at every stage of the process is very much advisable. Talk about how you feel, any unusual signs or symptoms you have noticed, and signs of improvement. If Provenge is not the best therapy for you, there are other treatment options your doctor may recommend. In all, it is best to work with your healthcare team and trust them to help you make the best-informed decision about your health.