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AIDS Candidate Drug GS-CA1 Shows Significant Effects In Primates

Release time:2021/12/10 16:36:52
Author:Huateng Pharma

GS-CA1, an inhibitor of the HIV capsid, can provide long-term protection with one injection and prevent macaques from bei…

AIDS, full name is Acquired Immune Deficiency Syndrome, which is a very harmful infectious disease caused by the human immunodeficiency virus (HIV). The HIV virus can attack and severely damage the human immune system. Therefore, AIDS patients often suffer from secondary infections or tumors due to insufficient immunity, which also makes the mortality rate of AIDS patients extremely high. 

HIV virus under electron microscope.png

 HIV virus under electron microscope  

On December 7, 2021, researchers from Harvard Medical School and Gilead Sciences published a research paper titled: Long Acting Capsid Inhibitor Protects Macaques From Repeat SHIV Challenges in Nature.

The study showed that GS-CA1, an inhibitor of the HIV capsid, can provide long-term protection with one injection and prevent macaques from being infected with Simian-Human Immunodeficiency Virus (SHIV). Such antiviral drugs may be expected to improve prevention methods to reduce the spread of HIV.

The use of antiretroviral therapy (ART) for pre-exposure prophylaxis (PrEP) is an important strategy to prevent HIV, but this method requires frequent administration, which limits compliance and effectiveness.

Long-acting antiretroviral drugs can solve the problem of daily drug dosage. The research team investigated the long-term preventive effects of a drug called GS-CA1 developed by Gilead Sciences, which exhibited anti-HIV effects in mice. GS-CA1 is a small molecule that can inhibit the HIV capsid. This target is very attractive because it plays a key role in virus replication.

This study showed that a dose of GS-CA1 can protect macaques and prevent the replication of simian-human immunodeficiency virus (SHIV). A total of 24 experimental animals were divided into three groups. The two groups received a dose of GS-CA1 (150 mg or 300 mg per kilogram of body weight), and the third group was the control group. The experimental animals were exposed to SHIV weekly for 15 weeks. In the highest-dose GS-CA1 group, all macaques had no detectable virus in the plasma at week 17, and 5 of them were still undetectable until the end of the study (24 weeks). A dose of 300 mg GS-CA1 per kilogram of body weight reduced the risk of infection per exposure by 97%.




The structure of GS-CA1 is similar to that of lenacapavir, another HIV capsid inhibitor, which has shown potential for antiviral activity in clinical trials. The authors pointed out that the therapeutic potential of GS-CA1 in non-human primates may help guide further clinical trials of these HIV capsid inhibitors to determine how long a single dose can provide protection.

In October 2020, researchers from the University of Utah and the University of Virginia published a research paper titled: Reconstitution and visualization of HIV-1 capsid-dependent replication and integration in vitroin the top international academic journal Science.

The research has fulfilled a decades-long dream of reconstructing the first steps of HIV infection in vitro. What's more, this study is the first direct evidence that HIV's viral capsid is not just a packaging structure, but an important part of the HIV infection process in its own right. This research also provides theoretical support for the development of AIDS drugs that target the capsid.


According to the UNAIDS report, as of the end of 2018, there were approximately 37.9 million people living with HIV and AIDS worldwide. Although with the continuous in-depth research on HIV and AIDS in the medical field, AIDS patients have been able to maintain a normal life for decades under the condition of proper medication control, but the number of new infections is still showing a continuous increase trend. For this reason, it is believed that the real breakthrough for HIV is prevention, which has further given birth to the development of the HIV vaccine market.

On August 19, 2021, Moderna announced that it has officially launched the Phase I clinical trial of the mRNA AIDS vaccine. It is expected to end in the spring of 2023. Moderna's method is different from that of previous AIDS vaccines. It prevents HIV virus from entering cells by producing broadly neutralizing antibodies against the virus. Due to the rapid development of mRNA COVID-19 vaccines in recent years, the clinical effect of mRNA AIDS vaccine is worth expecting.  

As a professional worldwide supplier of PEG derivatives and pharmaceutical intermediates, Huateng Pharma is committed to supplying small to large quantities of a rich selection of PEG derivatives and pharmaceutical intermediates to support customers research worldwide. We also supply some PEG products used in COVID-19 mRNA vaccines, such as DSPA, mPEG-DSPE, mPEG-DTA (ALC-0159) and so on. We also supply CAS NO.3775-73-3 and CAS NO.61477-40-5 with high quality, they are intermediates of dolutegravir, which is a prescription medicine approved by the U.S. FDA for the treatment of HIV infection.



[1] Long Acting Capsid Inhibitor Protects Macaques From Repeat SHIV Challenges 
[2] Reconstitution and visualization of HIV-1 capsid-dependent replication and integration in vitro