Fighting Cancer with Customized Vaccines

Many people would, no doubt, have wished many years ago there were something they could use to protect against cancer – just as you have for measles and polio. Precisely, we mean vaccines that help defend against germs.

Researchers have made giant strides in this regard in more recent years. There are now cancer vaccines that are thought to help you remain healthy. Customized cancer vaccines are also available for people with the dreaded condition. But can these be really beneficial as they seem? This article will help to answer that question.

What are Cancer Vaccines?

A vaccine is a drug that is prepared to help boost immune function. You can think of it as a biological preparation that supports active immunity to a particular pathogen. And talking about cancer vaccines, these are basically medicines that boost your immune system to fight against cancer cells.

Vaccines are usually given to healthy people to protect them against diseases or infections. This then means you may be able to protect yourself against tumor growth through cancer vaccines. However, these are not only preventative in nature; some are also used for treatment of people already affected by the disorder.

Cancer vaccines are usually developed using antigens that are associated with particular cancer forms. Researchers have also been able to develop synthetic or modified versions of these antigens. Some of the latter types are actually modified to produce greater immune responses.

Cancer Prevention Vaccines

Doctors may recommend these medicines for healthy people for protection against cancers. This is based on the idea that certain forms of the condition are caused by viruses. Such vaccines are targeted against these infective agents and thus prevent cancer. There are two main types of cancer prevention vaccines.

One type of these vaccines targets strains of human papillomavirus (HPV). These viruses are believed to play a role in oral, throat, cervical and anal cancers, among others.

There is also the hepatitis B vaccine to prevent HBV infection. This is relevant because experts think that long-term hepatitis B virus infection increases the risk of having liver cancer.

A number of cancer prevention vaccines are recognized by the U.S. Food and Drug Administration. They include Gardasil, Cervarix and Twinrix.

Cancer Treatment Vaccines

These medicines, as their name suggests, are used in cases where cancer is already present. Treatment vaccines help to improve your immune system's ability to fight against cancer cells.

It is important to note that these do not necessarily provide cure. Rather, they help to slow or stop the growth of cancer cells. Treatment vaccines can help to shrink tumors.

They may be useful for getting rid of remnant cancer cells, following other forms of therapy. People who have been able to beat the scary disorder may also get these preparations to prevent recurrence.

Typically, cancer treatment vaccines improve the ability of a patient's immune system to recognize antigens for destruction. They activate cytotoxic T cells and instruct them to attack cancer cells. T cells are able to pick up antigens present inside cancer cells.

Increase in production of antibodies is an effect of treatment vaccines. These antibodies can recognize and bind to antigens lying on the surface of cancer cells.

However, it is not as easy producing cancer treatment vaccines, compared to preventive medicines. This is mainly because they need to be able to produce more powerful immune responses, enough to deal with highly defiant cancer cells.

Researchers have developed a number of cancer treatment vaccines all the same. The first of such to be approved by the FDA was sipuleucel-T, also known as Provenge. This is specifically for men who have metastatic prostate cancer.

Customized Cancer Vaccines

These also go under names such as autologous or personalized cancer vaccines. They are preparations that use cells from a patient's own body to fight the disorder. Customized cancer vaccines may involve the use of immune system cells or cancer cells.

Immune system cell approach

We will illustrate this using sipuleucel-T, which is an example of customized cancer vaccines.

The customization process starts with extraction of white blood cells or dendritic cells from the body of the patient. As you may know, white blood cells are critical to your body's ability to fight infections and harmful invaders.

These cells are then modified to be able to recognize prostate cancer cells for elimination. After the modification, the immune cells are infused into the patient's body through a vein. These guide other immune cells to recognize and attack prostate cancer cells.

Cancer cell approach

It may also be decided to attack cancer with cancer cells. In this case, researchers get sample cells from a patient's tumor. They then proceed to modify such to become easy target for the immune system.

Next, the treated cancer cells are injected into the body of the patient. The immune system attacks and puts cancer cells out of action when infused. It then proceeds to apply the same treatment to other similar cells in the body.

Can Customized Vaccines Really Help Fight Cancer?

You may find it quite interesting and clear-cut how customized cancer vaccines are supposed to help. But experience has shown that theory isn't always the same as reality. It is not wrong, therefore, to still wonder if things will work as proposed.

Going by the evidence from treatment with sipuleucel-T, it seems likely that cancer patients may benefit from customized cancer vaccines. Researchers found that the preparation helped to increase survival of some men with metastatic prostate cancer by roughly four months.

The improvement reported in clinical trials might not seem very much significant. But, at least, it showed that there is positive effect from cancer treatment vaccines.

Small clinical trials published in Nature in 2017 suggested that customized or personalized cancer can offer protection against tumors. The researchers focused on neoantigens on the surface of cancer cells as potential targets for getting rid of these cells.

The papers in Nature had people with melanoma as subjects. Vaccines used in both trials helped to stimulate T cells – CD8+ and CD4+ cells – that attack cancer cells.

In one of the trials in Germany, eight of the 13 patients who didn't have visible tumors at the time of receiving the vaccines didn't develop any for well more than one year afterward.

Studies suggest that better results may be obtained when cancer treatment vaccines are combined with other forms of cancer therapy, including radiation therapy, chemotherapy, and surgery. Researchers are still trying to understand whether it is best to do this at the same time or one after the other.

Limitations and Side Effects

Unfortunately, cancer vaccines are only helpful to a point. It may be practically impossible to deal with advanced or huge tumors relying singly on these. This explains why some experts suggest combination with other forms of treatment.

Cancer vaccines, by their nature, are intended to improve immune response. But the efficacy in doing this depends heavily on the strength of a person's immune system. The elderly or the sick may not be able to produce strong enough immune response after getting a vaccine. Besides, certain cancer treatments may harm the immune system.

Cancer vaccines approved by the FDA are supposed to have great safety profile. But these are still capable of producing a variety of side effects. The reactions will vary among vaccines and individuals.

Possible symptoms from cancer vaccines include:

Swelling
Itchiness
Pain
Rashes
Nausea
Vomiting
Dizziness
Fever
Fatigue
Muscle ache
Breathing difficulties

These side effects should only last for a short while. It is best to consult a doctor when they persist.

Cancer vaccines could possibly lead to more serious medical conditions. These include systemic lupus erythermatosus, appendicitis, and pelvic inflammatory disease.

Other Vaccines and Clinical Trials

In addition to the cancer vaccines discussed earlier, researchers have found a number of others and work still continues. A good number of these have shown impressive promise in clinical trials, but are yet to get FDA approval.

Allogenic cancer vaccines are among these other forms. These are prepared from cancer cells that are not obtained from the patient. They are developed in a lab setting. A very appealing thing about these medicines is that they are less costly to produce, compared to autologous or customized vaccines. Melanoma, prostate cancer, and leukemia are some of the disorders they are currently being tested for.

There are also protein (peptide) cancer vaccines. These differ from others such as autologous and allogenic variants. The difference lies mainly in the fact that they only use parts of cells (proteins or peptides), not a whole, for fighting cancer. They are currently still under investigation, though.

It appears majority of cancer vaccines are still at the clinical trial stage. These investigations usually have specific targets in focus. It means to benefit from them you have to sign up to be a volunteer.

Some of the cancers that vaccines are being tested for currently include:

Leukemia
Bladder cancer
Cervical cancer
Breast cancer
Brain tumor
Lung cancer
Melanoma
Pancreatic cancer

It does seem like customized cancer vaccines offer a glimmer of hope in the search for cancer cure. However, the greater number of these is still under investigation and lack approval for now. They are only accessible via clinical trials.

Notable breakthrough in these investigations will especially be lauded for those cancers that currently lack effective treatment options.

REFERENCES

What are Cancer Vaccines? | Cancer.Net (https://www.cancer.net/navigating-cancer-care/how-cancer-treated/immunotherapy-and-vaccines/what-are-cancer-vaccines)

Cancer Vaccines Fact Sheet - National Cancer Institute (https://www.cancer.gov/about-cancer/causes-prevention/vaccines-fact-sheet)

Cancer Vaccines and Immunotherapy | History of Vaccines (https://www.historyofvaccines.org/content/articles/cancer-vaccines-and-immunotherapy)

Cancer vaccines | American Cancer Society (https://www.cancer.org/treatment/treatments-and-side-effects/treatment-types/immunotherapy/cancer-vaccines.html)

Personalized cancer vaccines show glimmers of success: Nature News & Comment (https://www.nature.com/news/personalized-cancer-vaccines-show-glimmers-of-success-1.22249)

Cancer vaccines | American Cancer Society (https://www.cancer.org/treatment/treatments-and-side-effects/treatment-types/immunotherapy/cancer-vaccines.html)