Anticancer drugs are weapons against cancer

In the struggle between humans and cancer, drug treatment is a very important measure. Effective anti-cancer drug treatment can help patients get a longer survival time. This article interprets the new knowledge of anti-cancer drugs for everyone. What are the types of anticancer drugs

At present, 130 to 150 kinds of anti-cancer drugs have been approved for marketing in countries around the world. There are 1,300 to 1,500 kinds of anti-cancer drug preparations prepared with these drugs. According to the classification of drug sources and mechanism of action, anticancer drugs can be divided into two categories, namely traditional cytotoxic anticancer drugs and non-cytotoxic anticancer drugs.

1. Traditional cytotoxic anticancer drugs. That is, the chemotherapeutic drugs we often say, whose function is mainly to inhibit the proliferation of cancer cells and induce apoptosis of cancer cells, thereby destroying cancer cells. Such as cisplatin, paclitaxel, 5-fluorouracil, cyclophosphamide and bendamustine.

2. Non-cytotoxic anticancer drugs. Including hormone drugs, targeted drugs and immunotherapy drugs.

Hormonal drugs

Certain hormone-dependent cancers, such as breast cancer, prostate cancer, thyroid cancer, cervical cancer, etc., their occurrence is related to hormone imbalance; the application of certain hormones or their antagonists can change the hormone imbalance in the human body, thereby inhibiting dependence The growth of sex cancer cells. Such as tamoxifen (suitable for women of any age) and exemestane (suitable for postmenopausal women), which are clinically used to treat breast cancer.

Targeted drugs

It acts on the unique signal pathway of cancer cells to achieve the effect of killing cancer cells, but it rarely damages or does not damage normal cells. In cancer treatment, targeted drug therapy can achieve the goal of improving the effect of disease treatment by accurately finding the target of disease treatment and accurately monitoring the disease state and treatment process. Therefore, patients treated with targeted drugs must undergo genetic testing in advance to find suitable therapeutic targets. For example, the classic anti-cancer drug imatinib mesylate (Gleevec) is effective against Philadelphia chromosome-positive chronic myelogenous leukemia (hereinafter referred to as chronic myeloid leukemia), but it is not effective against Philadelphia chromosome-negative chronic myeloid leukemia; gefitin Nitrile is effective for patients with non-small cell lung cancer that are positive for epidermal growth factor receptor (EGFR) and anaplastic lymphoma kinase (ALK), but not for wild-type mutant lung cancer.

At present, a variety of targeted drugs have been marketed in China, including small molecule targeted drugs imatinib mesylate (Gleevec), gefitinib and erlotinib, etc.; large molecule targeted drugs such as rituximab Monoclonal antibody, trastuzumab; etc. Indications include solid tumors such as lung cancer, hepatocellular carcinoma, gastric cancer and breast cancer, as well as blood tumors such as myeloid leukemia.

Immunotherapy drugs

As the name suggests, it is a method of using the body’s own immune system to treat tumors. It does not harm cancer cells by itself, but uses the ability of the human immune system to eliminate cancer cells to mobilize the immune system to attack tumors and achieve the purpose of treatment.

At present, the most widely used PD-1/PD-L1 inhibitor in clinical applications is to block the PD-1/PD-L1 pathway through drugs, activate the body’s own immune system, and attack tumor cells. Drugs that block the PD-1/PD-L1 pathway are called PD-1 inhibitors. There are two types of PD-1 inhibitors: anti-PD-1 monoclonal antibodies and anti-PD-L1 monoclonal antibodies. Anti-PD-1 monoclonal antibodies include nivolumab (trade name Opdivo, commonly known as drug O) and pembrolizumab (trade name Keytruda, commonly known as drug K); anti-PD-L1 monoclonal antibodies include atezolizumab (trade name Tecentriq, commonly known as T drug) and avilizumab (trade name Bavencio, commonly known as B drug). Drugs O and K have been approved in my country, and drugs T and B are under review.

In addition to the above PD-1 inhibitors, immunotherapeutic drugs include CTLA-4 inhibitors (ipilimumab), tumor vaccines (HPV vaccines) and the latest CAR-T cell therapy.

What are the advantages of PD-1/PD-L1 and CAR-T immunotherapy in fighting cancer

PD-1/PD L, CAR T and traditional anti-tumor treatments are quite different in efficacy and safety. The effectiveness of PD-1/PD-L is mainly reflected in the expression level of PD-L1 in tumor tissues. Before using PD-1 inhibitors, it is best to detect PD-L1 expression in tumor tissues. Taking non-small cell lung cancer as an example, if the detection of tumor tissue has high PD-L1 expression, that is, the expression rate is ≥50%, indicating that more than 50% of the tumor cells in the tumor contain PDL1. If treated with PD-1 drugs, the tumor shrinks It’s half possible. Currently, PD-1 inhibitors have been approved as first-line drugs for non-small cell lung cancer in many countries and regions. In China, lung cancer is the number one cause of cancer death, 80% of which are non-small cell lung cancer. The effective rate for Hodgkin’s lymphoma is close to 90%, melanoma is 40% to 50%, bladder cancer is 50%, and liver cancer is about 30%. It has not been proven effective for some tumors such as gastric cancer and pancreatic cancer.

I would like to remind those patients with non-small cell lung cancer that if your epidermal growth factor receptor (EGFR) gene mutation is negative and anaplastic lymphoma kinase (ALK) negative, you can be treated for PD-1. If you are EGFR, ALK gene mutation positive, it is recommended to take targeted therapy, using targeted drugs instead of PD-1 drugs. Because the effective rate of targeted therapy is 75%, while the effective rate of PD-1 therapy is only 45%. Moreover, the targeted drugs are oral drugs, which are much cheaper than PD-1 drugs. In fact, the US FDA also recommends the use of PD-1 drugs for treatment in the absence of EGFR or ALK mutations or targeted drug resistance.

In terms of safety, immunotherapy is the use of immunosuppressant PD-1 drugs to restore the activation state of T cells, and use the human immune system to release toxic factors to achieve the purpose of killing tumors. Because PD-1 drugs activate the immune system during application, they may cause inflammation in multiple organs or tissues, which is called immune-related adverse reactions. The more serious one is interstitial pneumonia caused by interference with the patient’s normal immune mechanism. Some adverse immune reactions, such as immune myocarditis, have a low incidence, but their severity is high, and doctors and patients need to be vigilant during medication.

The full name of CAR-T is Chimeric Antigen Receptor T Lymphocytes, which are human T cells that are genetically modified in vitro and then transfused into the body to identify and eliminate specific cells. First collect T cells from the patient’s own blood, genetically modify them in vitro, and transfer an artificially designed gene to the T cells through genetic modification. This artificially designed gene is like an “anti-cancer navigator” that can guide T cells to accurately reach and identify cancer cells, thereby initiating T cells’ killing program on cancer cells. The designed CAR-T cells can be cultured and grown in the laboratory, and when they reach billions, they are injected into the patient’s body and proliferate in the patient’s body. CAR-T cell therapy has shown good targeting, killing and durability in clinical trials. At present, two CAR-T drugs that specifically recognize CD-19 positive cells have completed clinical trials abroad, and have been approved by countries such as Europe, America and Japan for the treatment of advanced childhood acute B-cell lymphocytic leukemia and advanced adult B-cell lymphoma . CAR-T is a brand-new cellular immunotherapy method that brings new treatment opportunities to patients. At the same time, various adverse reactions may occur during the treatment process, which requires the attention of doctors, patients and their families.

In recent years, anti-cancer drugs have emerged one after another, and the efficacy of cancer has been greatly improved. However, many anticancer drugs are still not highly selective. While killing cancer cells, they will inevitably cause damage to normal cells. This is the main reason that hinders their efficacy. The most common adverse reactions of anticancer drugs include myelosuppressive manifestations such as neutropenia, anemia, and bleeding; gastrointestinal toxicity manifestations such as nausea, vomiting, constipation, and diarrhea; liver toxicity and nephrotoxicity.

How should we view the adverse effects of taking anticancer drugs? If certain cancer cells do not have suitable targeted drugs, or because of certain conditions, patients must choose a chemotherapy regimen with greater adverse reactions. Under the above circumstances, doctors are required to predict the adverse effects of anticancer drugs as soon as possible and carry out effective treatment to choose the best treatment plan for the patient. Compared with traditional chemotherapy regimens, targeted therapy and immunotherapy have fewer adverse reactions and are new options for patient treatment.

With the continuous deepening of precision medicine research, we have reason to believe that the adverse effects of anti-cancer drugs will become smaller and smaller, and the effective rate of cancer treatment will become higher and higher, which will greatly extend the survival of patients.