Report from the 27th Conference on Retroviruses and Opportunistic Infections (CROI) 2020
OK, so you all are probably wondering if I’m obsessed with long-acting therapies after the previous article and several others in this collection. Understand that because medication adherence affects the effective treatment of all diseases and many people have problems taking pills every day, long-acting therapies are seen as a way the improve medication adherence (see the article entitled “Medication Adherence….” dated July 3, 2019 ).
At the Conference on Retroviruses and Opportunistic Infections in March 2020, the top HIV research conference (held virtually), some new research looks very encouraging for what could be an important treatment. It belongs to a brand new class of drugs called Capsid Inhibitors that work differently from all of the available HIV medicines.
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So what is Capsid? Capsid is a specialized protein that envelopes the HIV genetic material. When viruses infect a cell, they inject the Capsid-encased genetic material into the human white blood cell, a CD4+ lymphocyte. In order for the virus’s genetic material to hijack the cell, it must be released from the Capsid encasing it. Capsid inhibitors can block the release of the HIV’s genetic material (viral RNA) so it cannot replicate. They can also block the assembly of new viruses that manage to be produced. This double action makes them very effective in blocking HIV replication.
GS-6207, a drug developed by Gilead Sciences Pharmaceutical company, was shown in the laboratory to halt HIV infections in blood cells at very low concentrations, meaning it is quite potent. In early clinical trials, drugs are referred by their chemical code number in the company, and not assigned an actual drug name until later. So the study presented here is the first exposure of humans to the drug GS-6207. The primary purpose of this study (called phase 1) is to demonstrate the safety of the drug in humans and determine which doses are most likely to produce the best effect. In this study, 8 people were assigned to each of six different doses. These people were infected with HIV and had not received any treatment yet, so they had virus in their blood. They received a single administration of the drug, which was given subcutaneously, or under the skin like a diabetic would take insulin.
The amount of drug and virus was measured in the blood for ten days. Then the patients were started on a regular HIV treatment regimen. The first result is that the drug was well tolerated with few side-effects. Importantly, by day 10 after the single injection of the drug, the amount of virus in the blood was reduced by 100-fold on average in people receiving the two highest doses. This effect would make this new drug among the most powerful, compared to the available treatments.
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Combining this drug with one or two other HIV meds would drive the amount of virus in the blood even lower, easily getting the virus to undetectable levels in the blood, the target goal of treatment. The study participants were then at this point switched to a standard HIV treatment regimen (Bictarvy – Bictegravir/emtricitibine/tenofovir alafenamide). With these encouraging results, the studies of GS-6207 move forward with researchers exploring dosing the drug once every 6 months!!
It is important to remember that this is a totally new class of drug. As the studies move forward, we will likely see this drug being effective in people newly diagnosed with HIV. But there are people who have been infected for decades and may have an infection that is resistant to many existing classes of drug, giving them few treatment options. For these patients, this drug could be life-saving. Stay tuned.
In the meantime, PLEASE CONTINUE TO FOLLOW COVID-19 PROTECTIVE MEASURES (wear a face mask and continue to social distance in public. IT WORKS!)!
