PD-1/PD-L1 immunotherapy is a new class of anti-cancer immunotherapy currently in the spotlight, designed to use the body’s own immune system to fight off cancer by blocking the PD-1/PD-L1 signaling pathway to cause cancer cell death, with the potential to treat many types of tumors. what exactly is the medical value of PD-1? If you can remember how the smallpox vaccine eradicated the infection of smallpox virus and eliminated the pockmarks on human faces back then; how the polio vaccine avoided polio and little ones never limped again; how many friends and relatives with bacterial infections were saved by penicillin, or how tuberculosis patients like sister Lin were cured by streptomycin, you will definitely be hopeful about PD-1. PD1 drugs take the stage PD-1 is short for Programmed Death-1, a cell membrane protein receptor that regulates a key post of immune cell function, and PD-L1 is a ligand that binds to PD-1 protein. In recent years, it has been found that once PD-L1 appears on the tumor cell membrane, the body’s lymphatic immune cells become blind, cannot see the tumor cells, or no longer treat the cancer cells as foreign cells. In this way, the cancer cells can grow without any worries and the patient has cancer. An example is easy to understand. In a martial arts drama, a master sword dancer can’t get into the water when he dances with his sword. This master is like a tumor cell, the sword in his hand is PD-L1, if he takes away the sword, it is the same as abolishing his kung fu, and it is very easy to break. So PD-1 antibody is a new anti-cancer drug specially designed by scientists to disable the tumor cell’s resistance function. It prevents PD-L1 from binding to PD-1, and tumor cells lose their amulet, as if they are facing the outside world naked, thus suffering immune attacks from lymphocytes. Tumor cells can occur in many tissues and organs in the human body, and as far as anti-tumor is concerned, the effect of PD-1 antibody is broad-spectrum, which has been included in clinical trials for lung cancer, kidney cancer, stomach cancer, colon cancer, ovarian cancer, breast cancer, skin cancer, etc. What is PD1 and what is its mechanism of action? Immunotherapy inhibits the function of PD-1, a “suicide molecule”, and prevents the immune system from committing suicide, so that the human immune system can detect and attack cancer cells and use its own immunity to treat cancer. 2.What drugs are currently available for PD1? Currently, there are two main drugs, keytruda and opdivo, referred to as k-drugs and o-drugs respectively. These two drugs are produced by two different pharmaceutical companies, but the principles are the same and the effects are similar. The overall cost of use is basically the same. Before that, they need to be tried after chemotherapy and targeting have failed. However, they are not applicable to all cancers, and the focus is on “PD-L1 high expression” cancer. 3.How to use the drug? Both k-drugs and o-drugs are usually given intravenously and finished within 60 minutes. If you feel any of the following during the infusion, please inform the doctor or nurse immediately: chills, itchy skin, rash, facial flushing, difficulty in breathing, dizziness, fever. 4.How is the drug delivered? The medication is aqueous and needs to be delivered at 2-8 degrees Celsius. After purchasing the medication the doctor will give an ice pack which can be kept for 8 hours. In addition, the doctor will write a doctor’s certificate for customs inspection, which means that the medication can legally pass through customs. 5.How to calculate the dosage of drugs? Take O medicine for example, the standard dose is 3 mg per kg of body weight. The content of each drug is 100 mg. It has been proved that if the patient is sensitive to this drug, there is no problem to lower the dose and lengthen the interval. But if the patient is not sensitive to this drug, it may not be effective to fight every day. 6.How much does the drug cost? The price of O drug. Now each shot is less than 20,000 RMB, and each shot is 100 mg. At present, the price of the latest PD-L1 drug Tecentriq is$12,500/month (sold in the United States), while the price of keytruda (100mg) in Hong Kong is HK$42,000/each, and the price of opdivo (100mg) is HK$28,000/each. 7.What kind of cancer does the drug target? What is the efficacy rate? Currently, the FDA approved indications are melanoma and non-small cell lung cancer, and advanced renal cell cancer. The overall efficiency (without screening, blind test) for non-small cell lung cancer is about 20%. However, since the mechanism of this drug is to activate the immune system, many patients with stomach cancer, liver cancer and even blood cancer are now on trial. 8.Is there any indicator to predict the effect of the drug? Whether the drug is highly expressed or not is the only indicator to predict the effect of the drug, and some studies have shown that the drug is more than 70% effective in patients with high PD-L1 expression. However, some studies have also shown that a significant proportion of PDL1-negative patients are also effective. Therefore, the vast majority of patients are currently blinded to the trial. 9.How can I use this drug? There are currently three ways: ① Go to your doctor in Hong Kong to buy it yourself. Only family members need to go, no need for the patient to go in person, and the doctor will not be responsible for the injection and treatment; ② go to an overseas hospital for treatment; ③ Oriental Hepatobiliary Hospital, where there is a person responsible for purchasing the drug and the hospital can administer the injection and treatment. 10.What are the side effects of the drugs? How should I deal with them? Please tell the doctor if the following symptoms occur seriously or continuously during the treatment: ① joint, back, jaw or bone pain; ② muscle pain; ③ hoarseness and dryness of voice; ④ redness of palms or soles; ⑤ mouth sores; ⑥ dry eyes; ⑦ hair loss. Please tell your doctor immediately if you experience any of the following symptoms during treatment: shortness of breath, persistent cough, abdominal pain, diarrhea, mood or behavior changes, etc. In general, the side effects are milder than those of the targeted drugs, and the better the patient’s constitution, the fewer the side effects will be. 11.Relationship with targeted drugs, can it be used in combination with targeted drugs? At present, PD1 is used only when chemotherapy and targeting have failed, and the direction of many clinical studies is to use PD1 in combination with certain targeting drugs. 12.How can I determine if the drug is working as soon as possible during the blinded trial? Based on tumor markers or CT examination results. Among them, tumor markers can quickly show whether the drug is effective or not. Before starting a blind drug trial, it is better to find a sensitive marker and measure the value before the drug is used. 13.Can I stop the drug after it takes effect? Some patients who have used it think they can. The reason is that the human immune system has a memory function, and this memory function is still there after the drug stimulation takes effect, so there is no need to continue using the drug. However, the specific course of treatment will be decided by the doctor according to the condition and patient’s situation. 14.Will PD1 be drug resistant? Theoretically, it is resistant to the drug, but since it can be stopped, the resistance can be prolonged as long as the frequency of drug use is controlled.