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- Moderna has administered the first doses of its mRNA-based HIV vaccine to volunteers in a clinical trial.
- The vaccine delivers instructions to specific HIV antigens that could potentially induce certain immune responses.
- Developing an HIV vaccine has taken decades, and mRNA technology can help speed the process.
The first doses of an experimental HIV vaccine that uses Moderna’s mRNA technology have been given to participants in a Phase 1 clinical trial, the company announcement Last week.
the test is conducted in partnership with the non-profit International AIDS Vaccine Initiative (IAVI). Researchers are testing whether an mRNA-based vaccine that delivers instructions for specific HIV antigens can induce certain immune responses.
These antigens, also called immunogens, were developed by scientific teams at IAVI and Scripps Research. A “proof of concept” essay last year found that one of these immunogens generated the desired immune response – priming the right types of B cells – in 97% of participants.
This assay delivered the priming immunogen itself to the cells. The current trial will use Moderna’s mRNA technology to provide the genetic instructions for the immunogen, which the cells will then use to make this protein.
Additionally, the researchers are testing a separate stimulatory immunogen – also delivered through the mRNA platform – to see if it can help B cells mature further in the right direction.
“We are extremely excited to advance this new direction in HIV vaccine design with Moderna’s mRNA platform,” said Dr. Mark Feinberg, President and CEO of IAVI, in a statement. declaration.
“The search for an HIV vaccine has been long and difficult, and having new tools, in terms of immunogens and platforms, could be the key to rapidly advancing towards an effective and urgently needed HIV vaccine. “
The new trial, funded in part by the Bill & Melinda Gates Foundation, is the first step in the process of guiding the maturation of certain types of B cells.
The ultimate goal is to stimulate the development of B cells that can produce broadly neutralizing antibodies that can target a wide range of HIV variants.
A possible vaccine using this method will likely involve multiple doses administered weeks to years.
Researchers will recruit 56 healthy HIV-negative adult volunteers for the ongoing clinical trial. Of these, 48 will receive 1 or 2 doses of the immunogenic priming vaccine, 32 also receiving the immunogenic booster vaccine. Eight people will only receive the vaccine for the booster immunogen.
Additionally, researchers will follow participants for 6 months after their last dose to examine their immune responses and monitor for potential safety issues.
He was
Since then, researchers have tried to develop an effective vaccine to protect against HIV – with several large-scale phase 3 clinical trials but without any real success.
One of the challenges of developing an HIV vaccine is that once the virus infects a cell, it replicates wildly, so an effective vaccine would essentially block all infection.
“Yes [HIV] going to trigger an infection, even if someone has been vaccinated, then that infection is lifelong,” said Dr Davey Smith, an infectious disease specialist and translational research virologist at the University of California, San Diego.
Even COVID-19 vaccines don’t provide this kind of comprehensive protection against infection. However, they still offer strong protection against serious illness, hospitalization and death.
The bar for an HIV vaccine is raised because of the need to prevent lifelong infection with the virus.
There are effective anti-HIV drugs which can reduce the replication of the virus in the body, but they do not eliminate the virus completely. These drugs can help people live long, healthy lives and reduce their risk of passing the virus on to others.
Early attempts at HIV vaccines aimed to induce the immune system to make neutralizing antibodies that inactivate the virus, for example by preventing it from infecting cells.
But HIV evolves rapidly to generate new variants, even more so than the flu virus.
Every year the season
In comparison, a to study estimates that the global diversity of influenza virus genetic sequences is comparable to the diversity of HIV sequences found in a single person carrying the virus.
The wide genetic variation of HIV makes it difficult to target the virus with a vaccine, as neutralizing antibodies generated in response to a vaccine may only work against a few strains of HIV.
More recent HIV vaccine research has focused on developing vaccines capable of generating broadly neutralizing antibodies that target parts of the surface of the virus that are identical for many strains.
This is the approach taken by the scientists at IAVI and Scripps. The challenge is to find the best immunogens to guide the maturation of B cells to produce these broadly neutralizing antibodies.
Moderna’s mRNA technology can help speed up this process because much of the vaccine design work can be done on a computer.
This ability helped researchers design candidate vaccines against COVID-19 days after Chinese scientists published the genetic sequence of SARS-CoV-2, the coronavirus that causes COVID-19.
“We have seen promising proof of concept for germline targeting in [last year’s trial], and this trial allows us to take the next step with this approach,” Guillaume Schief, PhD, professor at Scripps Research, said in the statement.
“Additionally, we were able to ramp up the production of clinical trial material at a remarkably rapid rate using Moderna’s technology,” he said.
Smith cautions against overhyping the current study, especially with HIV’s ability to evade the body’s immune responses, even those stimulated by vaccines.
“It’s a very, very high hill to climb for this new mRNA technology,” he said, “to generate a very broad and powerful immune response to protect against HIV.”
Still, he thinks there’s a lot to be gained from this research.
“They set up these trials very smartly, in my opinion, to learn as much as possible,” he said. “What is the immunogen that makes the immune system really go into overdrive? And what is going to help us protect people in the future from exposure to HIV?”
He is also grateful for the renewed interest in the search for an HIV vaccine.
While the World Health Organization (WHO) has given HIV the status of an “epidemic”, many argue that it should be called a “pandemic” because of the millions of people living with HIV around the world.
“We shouldn’t give up on the latest pandemic [HIV] simply because we are fighting the COVID-19 pandemic,” Smith said. “So I really commend the investigators for investigating a new technology to come up with an HIV vaccine, one that we still haven’t got even after nearly 40 years of trying.”
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