Targeted therapy is one of the most revolutionary milestones in cancer treatment within the last fifty years. Different from chemo–therapy and radiation therapy, which have effects on cancer cells and normal cells, targeted therapy can only act on cancer cells and minimize effects on normal cells and affiliated side effects.
In this guide, we will provide a thorough understanding of what targeted therapy is, how it works, its types, benefits, challenges, and the future of targeted treatments in cancer care.
What is Targeted Therapy?
Targeted therapy refers to a class of treatments that use drugs or other substances to precisely identify and attack cancer cells without harming normal cells. These therapies focus on specific molecules that are involved in the growth, progression, and spread of cancer. By targeting these specific molecules, targeted therapies can block the growth signals that tell cancer cells to divide uncontrollably.
How Targeted Therapy Works
Cancer cells have specific genetic mutations, proteins, or other factors that make them different from normal cells. Targeted therapy works by either blocking or interfering with these abnormalities, helping to prevent cancer growth and spread. There are several mechanisms through which targeted therapy works:
- Blocking the signals that tell cancer cells to grow and divide
Some cancer cells produce abnormal proteins or growth signals that instruct them to grow and divide. Targeted therapies can block these signals. - Interrupting blood flow to the tumor (Anti-angiogenesis)
Tumors need a blood supply to grow. Some targeted therapies work by preventing the formation of blood vessels that feed the tumor, essentially starving the cancer of nutrients. - Delivering toxic substances directly to cancer cells
Certain targeted therapies can deliver chemotherapy or radioactive substances directly to the cancer cells, limiting damage to normal tissues. - Boosting the immune system to fight cancer
Some therapies help the immune system recognize and attack cancer cells more effectively, a strategy known as immune modulation.
Types of Targeted Therapy
Targeted therapy can be broadly categorized based on the type of target and the mechanism of action. Here are the main types:
- Monoclonal Antibodies Monoclonal antibodies are laboratory-made molecules that can bind to specific targets on the surface of cancer cells. They are designed to attach to cancer cells and help the immune system recognize and destroy them. Some monoclonal antibodies also block growth signals. Examples include:
- Trastuzumab (Herceptin): Used for HER2-positive breast cancer.
- Rituximab (Rituxan): Used for certain types of lymphoma and leukemia.
- Small Molecule Drugs These are drugs that enter the cancer cells and target specific molecules inside the cell, such as enzymes or proteins, to stop the cancer from growing. Small molecule drugs can affect cancer cells by blocking the activity of specific proteins or by interfering with genetic information. Examples include:
- Imatinib (Gleevec): Used for chronic myeloid leukemia (CML) and gastrointestinal stromal tumors (GISTs).
- Gefitinib (Iressa): Used for non-small cell lung cancer (NSCLC) with EGFR mutations.
- Angiogenesis Inhibitors These drugs prevent the growth of new blood vessels (angiogenesis) that tumors need to grow. By blocking blood vessel formation, these therapies reduce the tumor’s nutrient supply. An example is Bevacizumab (Avastin), which is used to treat cancers like colon, lung, and kidney cancer.
- Cancer Vaccine Therapies These vaccines work by stimulating the body’s immune system to target cancer cells. They are different from traditional vaccines, which prevent disease. Cancer vaccines treat existing cancers by training the immune system to attack cancer-specific antigens. For example:
- Bacillus Calmette-Guérin (BCG): Used for bladder cancer.
- Sipuleucel-T (Provenge): Used for prostate cancer.
- PARP Inhibitors Poly (ADP-ribose) polymerase (PARP) inhibitors are a class of drugs that block cancer cells from repairing DNA damage. This leads to the accumulation of DNA damage in cancer cells, eventually causing their death. Examples include:
- Olaparib (Lynparza): Used for ovarian and breast cancers with BRCA mutations.
- Niraparib (Zejula): Approved for ovarian cancer treatment.
Benefits of Targeted Therapy
- Precision
Targeted therapy is more precise than traditional therapies because it focuses directly on the cancer cells and avoids damaging healthy tissues. This leads to fewer side effects compared to conventional chemotherapy and radiation. - Personalization
Targeted therapy is often used in combination with genetic testing. This allows doctors to tailor treatment based on the patient’s cancer’s genetic profile, making the treatment more effective. - Less Invasive
Many targeted therapies are oral medications or infusions, which means they don’t require surgery or long hospital stays. This convenience improves patients’ quality of life. - Effective for Specific Cancer Types
Targeted therapies are particularly effective in cancers with known genetic mutations or specific molecular characteristics, such as breast cancer, colon cancer, and leukemia.
Challenges and Limitations
While targeted therapy offers numerous benefits, there are some challenges associated with it:
- Resistance
Cancer cells can develop resistance to targeted therapies over time. They may alter their genetic makeup or activate alternate growth pathways, making the treatment less effective. - Side Effects
Although targeted therapies generally cause fewer side effects than chemotherapy, they are not without risk. Some targeted therapies may cause skin problems, high blood pressure, liver damage, or issues with the heart or lungs. - Cost
Targeted therapies are often more expensive than traditional treatments, which can create financial barriers for some patients. - Limited Availability
Not all cancers have specific targets for therapy, and the availability of targeted treatments depends on the type of cancer and the mutations present.
The Future of Targeted Therapy
The future of targeted therapy is incredibly promising. With ongoing research, new targets are being identified, and treatments are becoming even more personalized and effective. Some key areas of development include:
- Combination Therapies
Researchers are exploring how to combine targeted therapy with other treatment types, such as immunotherapy, chemotherapy, or radiation, to enhance effectiveness and overcome resistance.
- Next-Generation Targeted Drugs
New and improved targeted therapies are being developed, including those that target previously undruggable proteins or those that are more specific to cancer types with limited treatment options.
- Biomarker Discovery
Advances in genetic testing and biomarker discovery will allow for more precise targeting of cancer cells, leading to better treatment outcomes and fewer side effects.
- Liquid Biopsies
The use of liquid biopsies to identify cancer-specific mutations is expected to become a routine part of cancer care, helping doctors make quicker and more accurate treatment decisions.
Dr Pooja Babbar- exper Oncologist
Targeted therapy represents a major shift in the way cancer is treated, offering more personalized, precise, and effective options for patients. Dr. Pooja Babbar, with over a decade of experience in oncology, is at the forefront of this transformative approach.
As a highly skilled and compassionate medical oncologist, she has treated a wide range of cancers, having independently headed the department of medical oncology at CK Birla Hospital. During her career, Dr. Babbar has successfully administered thousands of chemotherapy sessions and precision oncology treatments, showcasing her expertise in the latest treatment protocols, including chemotherapy, immunotherapy, and targeted therapy.
Her unwavering commitment to personalized care ensures that each patient receives the best possible treatment tailored to their unique needs. Dr. Babbar’s innovative approach, coupled with her deep knowledge and dedication to patient well-being, has earned her the trust and respect of both her patients and peers in the field of oncology.
