So far, cancer drug development has gone through three huge revolutions; they are: cytotoxic chemotherapy drugs, “targeted therapy” and immunotherapy. Immunotherapy has not only revolutionized the effectiveness of cancer treatment and will revolutionize the concept of cancer treating. Relatively speaking, immunotherapy is the real anti-cancer revolution and the most reasonable means to solve cancer.
Chemotherapy- the first revolution of anti-cancer drugs
Starting from 1940, the most used anti-cancer chemotherapy drugs are basically belong to cytotoxic chemotherapy drugs currently in clinical.
The basic principle of chemotherapy is kill rapidly dividing cells. Different in mechanism, dozens of commonly used chemotherapy drugs are aimed to kill rapidly dividing cells. But it only seeks for fast dividing cells, do not distinguish whether they are malignant cells or normal cells, thus killing a large number of stem cells in its division. So chemotherapy dosage must be strictly controlled: less would not kill cancers and too much can cause serious side effects.
Targeted therapy-the second revolution of anti-cancer drugs
Targeted therapy was first studied in 1990s and applied into clinical use after 2000. The so called targeted therapy is chemotherapy drugs that only kill cancer cells without affecting normal cells. The discovery of oncogenes in 1970 made this idea become possible, because many oncogenes do not exist in normal cells. The first truly specific targeted drug is Gleevec launched in 2001 used for the treatment of BCR-ABL. The occurrence of Gleevec made the 5-year survival of BCR-ABL jumped from 30% to 89%. So this is obviously the second revolution of cancer drugs. The most brilliant figure of this method is its minimal side effects.
Immunotherapy-the third revolution of anti-cancer drugs
Compared with traditional chemotherapy or targeted therapy, the essence of immunotherapy is directed to immune cells instead of cancer cells, mobilizing the patients’ own natural anti-cancer immune function.
Traditional cancer treatments have three defects, while immune therapy has avoided these drawbacks. Traditional surgery, radiotherapy and chemotherapy goal is to remove or kill cancer cells directly, there are three flaws. One is that this method “kills a thousand enemies but lose eight hundred normal ones”, the treatment bring great harm to the patients, so do their immune function. Secondly, cancer cells at not the same, but the majority of anti-cancer drugs, particularly targeted drugs, is only valid for a specific type of cancer. Thirdly, the cancer cells will continue to evolve, prone to drug resistance, leading to high rate of cancer recurrence. In theory, immunotherapy can avoid the three defects mentioned above: 1. No damage but enhance the immune system; 2. Treat a variety of cancers theoretically; 3. Strong immune system to inhibit cancer cells from generating drug resistance, reducing cancer recurrence rate.