There are many different types of targeted drugs that can be grouped according to the effect they have or categorized based on which cancers they are applicable.

1. Breast cancer
About 20% to 25% of cancer cells in breast cancer patients are due to excessive expression of the receptor protein on the surface of HER2, which promotes the growth of breast cancer cells. A number of targeted drugs, such as Herceptin, have been targeted against HER2 to treat cancers that are HER2-positive. Another inhibitor- aromatase inhibitors can also be used as endocrine therapy for breast cancer treatment.

2. Colorectal cance
Many colorectal cancer cells have a high level of EGFR, and Erbitux, a targeted drug for EGFR attacks, has an opportunity to inhibit cancer cell growth. The targeted drug "Avastin", which inhibits angiogenesis, is also used to treat certain patients with metastatic colorectal cancer.

3. Lung cancer
Some cancerous cancer cells have mutations in EGFR, while targeted drugs targeting mutant EGFR attacks, such as Iressa, Tarceva, and the second-generation drug "Took" (Giotrif) is effective in treating such lung cancer patients. In addition, patients with mutations in the ALK or ROS1 gene can be treated with Crizotinib.

4. Melanocyte cancer
About half of the melanocytic cancer cells have mutations in the BRAF gene, and the FDA has approved several targeted drugs for mutated BRAF protein attacks, such as Zelboraf, which can be used to treat patients whose tumor cannot be surgically removed or metastasized. .

It should be noted that targeted drugs also have shortcomings.
Current targeted drugs, if used properly, are usually effective in controlling cancer, with fewer side effects, and even some lucky patients can be completely cured. However, most patients will still develop drug resistance after a period of treatment. At this time, other feasible targeted drugs or traditional radiation and chemotherapeutic drugs must be used instead. In addition, if some of the cancer cells are effective in inhibiting the activity, they will certainly help cancer treatment, but it is difficult to develop drugs due to the complicated structure and function.

Different types of targeted drugs can cause side effects of different forms, which mainly depends on the individual's constitution. The most common side effects are diarrhea and liver function, other side effects such as weakness, elevated blood pressure, lighter hair color, skin and nail variation may also occur. Serious side effects such as intestinal and gastric perforation rarely occur. It is worth noting that there are drugs that can be prescribed by doctors to alleviate and prevent these side effects. Besides, most of the side effects of drugs will gradually disappear after stopping the drug.

Future Trend for Targeted drugs
Many major international pharmaceutical companies continue to target new drug development. Among them, a large number of novel small molecule inhibitors such as PDGFR, FLT-3, and IGF-1R are inhibitors of various cell surface receptors involved in cancer development and deterioration. There are also pharmaceutical companies that have developed “multi-targeted drugs” that can attack more than two targets at the same time, such as lapatinib, vandetanib, etc. Big pharmaceutical companies are also actively developing intracellular signaling pathway inhibitors, such as mTOR inhibitors (temsirolimus, everolimus), which have a double-pronged effect of inhibiting cancer cells and tumor angiogenesis; while Raf inhibitors (sorafenib) and MEK inhibitors (CI) -1040) are also being gradually developed and tested. Another major target for the development of targeted drugs is the regulation of chromosomal structures and gene expression enzymes in the nucleus, such as HDAC inhibitors (vorinostat) and drugs that cause DNA demethylation (azacitidine). All are at different stages of development. If each of these targeted drugs can be used to treat cancer patients, or with a combination of various drugs, it will provide unlimited development and long-term progress in cancer treatment.

However, attention must be paid to the combined use of targeted drugs, as this new practice may exacerbate or create new therapeutic toxicities and side effects, and the high cost of targeted drugs has caused a heavy financial burden on individual patients, which is also very likely to hinder the ongoing research on targeted drug development.

Author's Bio: 

This article is written by scientists at BOC Sciences, for the purpose of bringing about some basics of biochemistry to the public.