CANCER DRUGS: SUBTYPES AND MECHANISMS OF ACTION

There are many types of cancer treatment drugs . The choice of medication will be different for each patient.

What are cancer drugs ?

Cancer treatment drugs are drugs approved by international and domestic organizations; It is used to treat cancer, as well as to prevent cancer from coming back. For therapeutic purposes, it can be radical treatment (complete cure of the disease) in the early stages; or symptomatic relief treatment in advanced stages of disease metastases to other organs in the body.

There are many types of cancer drugs that are grouped according to their mechanism of action and purpose of treatment.

Types of cancer drugs and their mechanism of action

Chemotherapy drugs

As a group of cytotoxic drugs that damage DNA and kill cancer cells as well as healthy cells (for this reason, chemotherapy drugs often cause side effects related to damage to healthy cells such as hair loss). hair, vomiting, lack of blood cells, etc.).

Chemotherapy drugs can be used as monotherapy (using only one drug), or multi-chemotherapy (a combination of drugs), or in combination with other treatments. Chemotherapy drugs differ in their chemical composition, mechanism of action, dosage, and administration, as well as in their effectiveness and side effects.

The same cancer drug, but depending on the use (monotherapy, or multiple chemotherapy, or in combination with other treatments), the way to use the drug will be different.

Chemotherapy drugs can be grouped according to how they work, their chemical structure, and their relationship to other drugs. Some drugs work in more than one way and can belong to more than one group. There are the following classes of chemotherapy drugs:

group of alkylating agents

Alkylation agents prevent the cell from making copies of itself, by damaging the cell’s DNA. This class of drugs is used to treat many different cancers, such as lung, breast and ovarian cancer, leukemia, lymphoma, multiple myeloma, and sarcoma.

Group Nitrosoureas

Nitrosoureas are also a group of alkylated substances, but have more special properties that can be dissolved in fat, so they can penetrate the blood-brain barrier to enter the brain; while the other alkylation agents listed above cannot do this. Therefore, the Nitrosoureas group is often used to treat certain types of brain tumors.

Anti-metabolite group

Anti-metabolites interfere with DNA and RNA synthesis, so DNA and RNA cannot make copies of themselves and cells cannot reproduce. This class of drugs is commonly used to treat leukemia, breast, ovarian, and intestinal cancers, as well as other types of cancer.

Anti-tumor group of antibiotics

These drugs are different from the class of antibiotics used to treat infections.

The drug prevents cell division by interfering with the synthesis of DNA and RNA inside cancer cells, making it impossible for cancer cells to multiply and grow.

  • Anthracyclines antibiotics: are widely used to treat many types of cancer, including drugs such as Daunorubicin, Doxorubicin, Doxorubicin liposomal, Epirubicin, Idarubicin, Valrubicin…
  • Non-Anthracycline Antibiotics: Besides Anthracyclines, there are other non-Anthracyclines anti-tumor antibiotics such as Bleomycin, Dactinomycin, Mitomycin-C, Mitoxantrone (also acts as a topoisomerase II inhibitor).

Topoisomerase inhibitors class

Topoisomerase is an enzyme that separates strands of DNA before replication can take place (enzyme = a protein that helps trigger chemical reactions in cells).

These drugs are derived from plant alkaloids, which inhibit Topoisomerase, making DNA unseparable, from which it cannot be copied; This means that cancer cells cannot divide and proliferate. This class of drugs can be used to treat some leukemias, lung, ovarian, gastrointestinal, colorectal, and pancreatic cancers.

There are two classes of Topoisomerase inhibitors: Topoisomerase I inhibitors and Topoisomerase II inhibitors.

  • Topoisomerase I inhibitors (also known as Camptothecins) include drugs such as Irinotecan, Irinotecan liposomal, Topotecan, etc.
  • Topoisomerase II inhibitors (also known as Epipodophyllotoxin) include drugs such as Etoposide (VP-16), Mitoxantrone (which also acts as an anti-tumor antibiotic), Teniposide, etc.

The class of drugs that inhibit cell division

The class of mitotic inhibitors is usually derived from plant alkaloids. This class of drugs prevents cells from dividing to form new cells, but can damage cells in all stages by preventing enzymes from making substances needed for cell reproduction.

The class of mitotic inhibitors can be used to treat breast, lung, myeloma, lymphoma, and leukemia cancers.

Corticosteroids

Corticosteroids, commonly known as steroids, are naturally occurring hormones. Hormone-like drugs are commonly used to treat many types of cancer, as well as other diseases. When these drugs are used as part of cancer treatment, they are considered chemotherapy drugs.

Corticosteroid drugs include Prednisone, Methylprednisolone, Dexamethasone …

Corticosteroids can also be used to prevent nausea and vomiting caused by chemotherapy . In addition, corticosteroids may be given before chemotherapy treatment to help prevent serious allergic reactions.

Other chemotherapy drugs

There are a number of chemotherapy drugs that do not act according to the above groups such as all-trans-retinoic acid, Arsenic trioxide, Asparaginase, Eribulin, Hydroxyurea, Ixabepilone, Mitotane, Omacetaxine, Pegaspargase, Procarbazine, Romidepsin, Vorinostat…

Targeted therapy for cancer

Targeted cancer drugs will directly attack the differences of each type of cancer cell, thereby helping to quickly kill cancer cells and cause less damage to healthy cells.

The effects of targeted cancer drugs are:

  • Search for cancer cells and destroy them.
  • Prevent cancer cells from dividing and growing.
  • Encourages the immune system to attack cancer cells.
  • Blocks blood vessels that feed cancer cells.
  • Helps deliver other treatments such as chemotherapy directly to cancer cells.

There are many different types of targeted cancer drugs, grouped according to their mechanism of action. Some targeted cancer drugs may also be called biologics.

Classes of targeted cancer drugs include:

Monoclonal Antibody (MAB = Monoclonal AntiBody)

Antibodies in the blood help fight infection. MAB therapies mimic natural antibodies but are made in a laboratory. Single line means all one type. So each MAB therapy is a lot of copies of an antibody.

Many different MABs are available to treat cancer, and they work in different ways.

All monoclonal antibody drugs are named with the drug name + final mab formula. Examples: trastuzumab (Herceptin), pertuzumab (Perjeta), bevacizumab (Avastin), rituximab (Mabthera), docstarlimab.

Drugs that prevent cancer growth

A cancer growth suppressor is a targeted drug that blocks growth factors that trigger cancer cells to divide and grow. Scientists are looking at different ways to do this such as:

  • Decreased levels of growth factors in the body.
  • Blocks growth factor receptors on cancer cells.
  • Blocks the signals inside the cell that kick in when growth factor activates the receptor.
  • Most of these treatments work by blocking the signaling processes that cancer cells use to divide.

Cancer suppressants come in different types and can be grouped according to the type of chemicals they block. Examples include tyrosine kinase inhibitors, proteasome inhibitors, mTOR inhibitors, PI3K inhibitors, histone deacetylase inhibitors, hedgehog transducers, BRAF and MEK inhibitors.

Drugs that block the growth of cancerous blood vessels

Antiangiogenic drugs are treatments that stop the blood vessels in the tumor from growing. If the drug can stop the growth of blood vessels in the tumor, it can slow the growth of the cancer or sometimes shrink the tumor.

There are different drugs that block the growth of blood vessels:

  • Drugs that block blood vessel growth factor:

A drug that blocks vascular endothelial growth factor (VEGF) from binding to receptors on cells lining blood vessels to prevent blood vessels from growing.

One example that blocks VEGF is bevacizumab (Avastin). Bevacizumab is also a monoclonal antibody used to treat several different types of cancer. Other examples include aflibercept, ramucirumab.

  • Drugs that block signaling in cells:

A drug that blocks VEGF receptors from sending growth signals into blood vessel cells. These treatments are also known as cancer growth suppressors or tyrosine kinase inhibitors (TKIs).

Examples of TKIs that block signaling inside blood vessel cells include sunitinib, sorafenib axitinib, regorafenib, cabozantinib.

  • Drugs that affect signaling between cells:

Drugs that act on chemicals that cells use to signal each other to grow, to prevent the formation of blood vessels.

Drugs that work this way include thalidomide and lenalidomide (Revlimid). They are used to treat multiple myeloma.

PARP . Inhibitors

A cancer treatment that uses PARP inhibitors to stop PARP from doing its job of repairing cancer cells and the cells that die.

The researchers first looked at these drugs in cancers that involve a change (or error) in a gene called BRCA.

Normally, the BRCA1 and BRCA2 genes play a part in the body’s cell repair process. Cells are less able to repair themselves if there is an error in one or both of these genes. People with faulty BRCA genes have an increased risk of certain cancers, such as breast cancer, ovarian cancer, and prostate cancer.

Cancer cells with faulty BRCA genes already have a poor repair system. Thus, blocking PARP with a PARP inhibitor means rendering the cells incapable of self-healing and dying.

PARP is used to treat cancers including ovarian cancer, fallopian tube cancer, and peritoneal cancer. In addition, it has also been tested in other types of cancer such as lung cancer, pancreatic cancer, head and neck cancer, a type of brain tumor known as glioblastoma multiforme, prostate cancer. paralysis, stomach and esophageal cancer, uterine and cervical cancer, kidney and bladder cancer.

There are different types of PARP inhibitors including olaparib (Lynparza), rucaparib (Rubraca), niraparib (Zejula).

Endocrine therapy drugs

Hormones are proteins or substances made by the body to help control how certain types of cells work. For example, some parts of the body rely on sex hormones such as estrogen, testosterone, and progesterone to function properly. There are many other hormones in the body, such as thyroid hormones, cortisol, adrenaline, and insulin. Different hormones are made by different organs or glands.

Some cancers depend on hormones to grow. Therefore, treatments that block or change hormones can sometimes help slow or stop the growth of these cancers. Treating cancer with hormones is called hormone therapy, hormone therapy, or endocrine therapy. Hormone therapy is mainly used to treat certain types of breast cancer and prostate cancer that depend on sex hormones to grow. Some other cancers can also be treated with hormone therapy.

Hormone therapy is considered a systemic treatment because the targeted hormones circulate throughout the body. The drugs used in hormone therapy travel throughout the body to target and find the hormones. This makes it different from treatments that affect only a certain part of the body, like most types of surgery and radiation therapy.

How hormone therapy works:

Different types of hormone therapy work in different ways:

  • Prevents the body from making hormones.
  • Block hormones from attaching to cancer cells.
  • Change the hormone so it doesn’t work as it should.

Hormone therapy may be used to:

  • Treating a certain type of cancer by stopping or slowing the growth of cancer cells.
  • Reducing symptoms associated with a certain type of cancer.

Some examples and types of cancer that endocrine therapies may be used to treat.

  • Breast cancer: Aromatase inhibitors (AIs) such as anastrozole, exemestane and letrozole; selective estrogen receptor modulators (SERMs) such as tamoxifen and raloxifene; estrogen receptor antagonists such as fulvestrant and toremifene; luteinizing hormone-releasing hormone (LHRH) agonists such as goserelin, leuprolide, and triptorelin; surgical removal of the ovaries.
  • Prostate cancer: Anti-androgen drugs such as apalutamide, enzalutamide, darolutamide, bicalutamide, flutamide, and nilutamide (also known as androgen removal therapy or ADT); CYP17 inhibitors such as abiraterone and ketoconazole; luteinizing hormone-releasing hormone (LHRH) agonists and antagonists such as goserelin, leuprolide, triptorelin, and degarelix; orchiectomy surgery.
  • Endometrial cancer (the lining of the uterus or uterus): Progestins such as medroxyprogesterone acetate or megestrol acetate; selective estrogen receptor modulators (SERMs) such as tamoxifen and raloxifene; luteinizing hormone-releasing hormone (LHRH) agonists such as goserelin and leuprolide; Aromatase inhibitors (AIs) such as letrozole, anastrozole, and exemestane.
  • Adrenal cancer: Adrenolytics such as mitotane; estrogen receptor antagonists such as fulvestrant and toremifene; selective estrogen receptor modulators (SERMs) such as tamoxifen and raloxifene.

How are cancer drugs used?

Cancer drugs can enter the patient’s body in many different ways. Among them, the most popular is.

Intravenous

The nurse or doctor attaches a syringe to the infusion tube to inject the medicine. Cannula tubes have a rubber stopper on them and they can inject medication through the rubber stopper.

Some cancer drugs are diluted in a bag of liquid and people take them as drops.

The nurse attaches the dropper bag to the catheter or central line and the medicine goes into the vein in 20 minutes or hours. Some medications are given this way for several days with a small electronic pump that will be used to keep the dose rate constant.

Intramuscular

Some medications are injected into a muscle (intramuscularly), usually in the buttocks or upper thigh. Patients may experience stinging or dull pain for a short time after the injection.

Subcutaneously

Patients are usually injected under the skin in the abdomen, thigh or upper arm. After the injection, the person may experience stinging or dull pain for a short time, but usually not much pain. The skin in this area may be red and itchy for a while.

Circuit transmission

An intravenous infusion usually enters the body in the middle of the chest, then the drug is sent under the skin to a large vein near the collarbone.

PICC line

PICC stands for peripherally inserted central catheter. The medicine is given into a vein under your arm and ends up in a large vein in your chest. This procedure is usually performed under local anesthesia.

PICC lines can be left in place for several months and are used in a similar way to an arterial infusion method.

Portacaths

A portacath is a specific type of central line, which has a small cavity or reservoir that is located under the skin but is difficult to see with the naked eye.

The nurse will insert a needle into the chamber and inject or attach a dropper. The needle remains in place until the treatment is done. The nurse then withdraws the needle until the next treatment.

Side effects of cancer drugs

Cancer drugs often cause common side effects such as fatigue, hair loss, loss of appetite, nausea, musculoskeletal pain, bone loss, and risk of fractures. There is also a high risk of other cancers, stroke, blood clots, cataracts and heart disease, weight gain, memory problems, and more.

Hormone drugs alone can cause hot flashes, decreased sex drive, vaginal discharge, dryness or irritation in women, and erectile dysfunction in men.