Recently, the second generation of tenofovirTenofovir fumarate tablets (TAF)in
This is also the only new hepatitis B drug approved in China in the last five years. Tenofovir fumarate tablets (Velde), known as "the most potent hepatitis B drug in history", are used primarily in the treatment of chronic hepatitis B in adults and adolescents (12 years of age and over 35 kg). HBV).
Friends who are familiar with the treatment of hepatitis B may be confused here. Is not it too long for Norfolk to be on the market? Why do propofol fumarate tablets become a new "re-listed" drug? Let's talk in detail today!
How do two drugs treat hepatitis B?
Tenofovir disoproxil fumarate (Wired) tablets were launched as an anti-HIV drug in 2013 and were approved in 2014 to broaden indications for the treatment of hepatitis B.
As tenofovir is hardly absorbed by the gastrointestinal tract, it must be esterified and salted before being absorbed and used by the body. After being hydrated and phosphorylated, it forms tenofovir diphosphate.
Tenofovir diphosphate is similar in structure to deoxynucleotide, one of the molecular materials of DNA, and is fused to the DNA molecule by "disguising", causing the tail of the DNA molecule chain to lack the necessary structure, thereby interrupting the extension of DNA. .
That is, the DNA molecules are cut in disguise, and the virus can not "copy" its own "code of life", thus suppressing the virus.
And the new drug that has just been approved for marketing –Tenofovir fumarate (Velde) is a tenofovir phosphoramide prodrug that can be hydrolyzed and phosphorylated in hepatocytes to be converted to tenofovir diphosphate.
Although the two drugs have the same goal, they will eventually be converted to tenofovir diphosphate. The process in the body is almost the same – hydrolysis, phosphorylation, but the two drugs in the body, dose, efficacy, ".
What is the difference between the two drugs?
Tenofovir disoproxil fumarate tablets (hereinafter referred to as TDF) have been popularly listed.The strong antiviral effect and low rate of drug resistance are the most characteristic of TDF.
Not only recommended as the first treatment option in the 2015 edition of the Guidelines for the Prevention and Treatment of Chronic Hepatitis B but also as a patient with hepatitis B in the 2016 edition of the Consensus on Antiviral Therapy for Chronic Hepatitis B Analogs ) The drug of choice after treatment failure.
Compared to other antiviral drugs, TDF has a higher level of safety in pregnancy. Pregnant women with hepatitis B can use TDF treatment to reduce the possibility of treatment failure due to drug resistance and also prevent maternal block and childhood hepatitis B to ensure the baby's health.
Although TDF has so many advantages as mentioned above, it also has its shortcomings.In the long-term treatment of PTO, there is a risk of kidney damage in some special patients. At the same time, PTO also reduces the patient's bone density and adversely affects the patient's bones.
Tenofovir fumarate tablets (hereinafter referred to as TAF) were modified on the basis of TDF to form a "ME BETTER" drug.
TAF can reduce the effects of kidney damage and bone density. Previous clinical data showed that patients with FAT had more stable kidney function and bone density without significant damage.
Another clinical study found that patients with TDF switched to TAF had better renal function and bone density, and liver function indicators were restored more rapidly.
Second-generation tenofovir (TAF) is safer and better than first generation (TDF) and is, in fact, the gospel of patients with hepatitis B.
In addition, TAF can be "concentrated" in the liver, reducing the concentration of drugs in the peripheral blood and "concentrating forces" to attack the "enemy stronghold", which also reduces the dose and frequency of TAF. better compliance.
What is the price trend of this new drug?
With the drug listing, patients see the dawn of treatment, but that dawn also carries a little mist, that is, the monopoly and the high prices brought by the new drugs.
To develop a new drug, a pharmaceutical company invested enormous human, financial and material resources. The cost of researching and developing new drugs is high and, if not adequately protected, companies will lose their research and development power, so patent protection of new drugs is very much needed.
But this patent protection is not a good thing for the patient, because this patent protection usually carries the high price of the drug.
During the drug patent protection period, other manufacturers can not provide inexpensive alternative drugs through imitation. This makes patients discouraged from expensive new drugs.
In this regard, we must be objective and dialectical, and blindly reducing the price of new drugs is not conducive to the development of new drugs and the development of medicine in the long run. I believe that in the future we will be able to buy a good medicine and use new medicines.
Expert of this article: Li Wensi, Ph.D. in Clinical Pharmacy, Zhongshan Hospital, Fudan University