Certain viral infections trigger cancer progression among healthy adults. Vaccination for such types of viral infection can give protection against such cancers from healthy individuals. But vaccination can only work if it is administered before the onset of the viral infection. Yet now, the U. S. FDA has approved two different vaccines for preventing cancers.
These are as follows:
HPV vaccine: This vaccine prevents human papillomavirus (HPV) infection. The HPV remains in the body for a prolonged period and can cause cervical cancer, vulvar cancer, anal cancer, and genital warts. HPV vaccination can prevent these cancers.
Hepatitis B vaccine. This vaccine prevents the hepatitis B virus (HBV) which can cause liver cancer.
Vaccine for cancer treatment
Some vaccines are used to treat cancer. Such types of cancer vaccines are classified under immunotherapy. The aim of giving these vaccines is to boost the immunity of the individual to fight against cancer. Oncologist prescribes this treatment to the cancer patients. However, every therapeutic vaccine has its own mechanism of action. They can
- Prevent cancer growth and spreading
- Prevent recurrence
- Destroy cancer cells that remain after the end of the treatment.
How do therapeutic cancer vaccines work?
Antigens are harmful substances that attack the cell surface. Immediately, the immune system of the body counter attacks the antigens to get rid of them. However, the immune system also captured those antigens against which it acts as a ‘memory’ for the future.
Therapeutic cancer vaccination boosts the immune system to fight and destroy the antigens. Cancer cells usually have specific antigens that are not present in the healthy cell surface. Therapeutic cancer vaccination allows entering the cancer-specific antigen to cancer affected person to identify the immune system which cells have such molecule to destroy them.
Sometimes therapeutic cancer vaccines are personalized. Personalized cancer vaccines are made for the individual patient depending upon the specific nature of the tumor which cannot be removed through surgery.
Some therapeutic cancer vaccines are specifically targeted certain types of cancer antigens and they are not personalized. Oncologist prescribes these vaccines to those cancer patients who have such specific type antigen in their cancer cell surface.
Usually, patients need to enter the clinical trials to get such a therapeutic cancer vaccine.
Sipuleucel-T (Provenge): The FDA approved sipuleucel-T (Provenge) in 2010 for patients with metastatic prostate cancer, which spread to other parts of the body. A series of steps followed during the treatment phase with Sipuleucel-T and it has tailored for each person:
- White blood cells are separated from the patient’s blood. White blood cells have a defensive mechanism of the body.
- Laboratory modification alters the white blood cell (WBC) mechanism to target prostate cancer cells.
- Then, the doctor re-administrated the modified white blood cells into the cancer patient through an intravenous route. The process is similar to blood transfusion.
- These modified WBCs help the immune system to identify and destroy prostate cancer cells.
This treatment is usually prescribed for patients who do not show effective response by treating hormonal therapy. However, Sipuleucel-T has some mild side effects such as fever, chills, fatigue, headache, joint and back pain, and nausea. But some patients may experience severe symptoms including breathing difficulty, hypertension, etc.
Talimogene laherparepvec (T-VEC): This vaccine is approved to treat advanced melanoma skin cancer. This vaccine is composed of a herpes virus. Laboratory alteration of this virus produces cytokine to boost the immune system. The side effect includes short-term flu-like symptoms.
Apart from this, the BCG vaccine which is formulated by Bacillus Calmette-Guérin bacteria in a weakened form injected to activate the immune system to treat early-stage bladder cancer.
What are Vaccines are in pipeline?
Several ongoing clinical trials try to investigate the efficacy and safety of different vaccines to treat bladder cancer, brain tumors, breast cancer, cervical cancer, colorectal cancer, kidney cancer, lung cancer, leukemia, pancreatic cancer. But yet now, none of the products get official approval.
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