A new study has found that just one infusion of an antibody called VRC01 can safely suppress the level of HIV in the blood of people who are not taking antiretroviral therapy (ART), the National Institutes of Health (NIH) announced late December 23, 2015
The phase I trial included 23 volunteers, 15 on ART and eight not on ART. Those on ART received two infusions of VRC01 28 days apart, and the others received just one infusion.
“The researchers found that while antibody infusions did not reduce the amount of HIV in blood cells, they reduced plasma viral load more than 10-fold in six of the eight people who were not on ART,” the NIH reported in a news release. “In the two people in this group who began the study with the lowest viral loads, the antibody suppressed HIV to extremely low levels for approximately three weeks – as long as VRC01 was present at therapeutic concentrations. In the other four people whose HIV levels declined, their viral load fell substantially but did not reach undetectable levels.”
Related HIV Equal News: Phase III trials have begun for Injectable Antibody to Fight HIV
Scientists later discovered that in two people on ART whose viral loads did not decline with the antibody, the predominant strain of HIV in their bodies “had been resistant to VRC01 at the outset,” adding, “The antibody also did not appear to have any effect in people taking ART whose virus was already suppressed.”
The results of the research appeared Dec 23, 2015 in the journal Science Translational Medicine.
“As therapeutic agents, (monoclonal antibodies) could be used to suppress active virus replication, maintain suppression induced by antiretroviral therapy (ART) and/or decrease the size of the persistent virus reservoir,” scientists reported in the research abstract. “In summary, a single infusion of mAb VRC01 significantly decreased plasma viremia and preferentially suppressed neutralization-sensitive virus strains. These data demonstrate the virological effect of this neutralizing antibody and highlight the need for combination strategies to maintain virus suppression.”
PRO 140 trials get FDA boost
Meanwhile, clinical trials have entered phase III for a similar approach to treat HIV using antibodies. PRO 140 is a manmade antibody manufactured by CytoDyn. On Monday, the U.S. Food and Drug Administration (FDA) granted CytoDyn “relaxed entry” status for those trials.
Initially the trials were limited to enrollment of patients resistant to HIV drugs in two or more classes. Now patients only need to demonstrate resistance to one class of drugs. “These patients must demonstrate evidence of HIV-1 replication despite ongoing antiretroviral therapy and have limited treatment options,” CytoDyn reported Monday in a news release.
“We are pleased that the FDA has granted CytoDyn relaxed entry criteria for subjects in our ongoing phase III trial to include patients with a single drug resistance,” CytoDyn President and CEO Dr. Nader Pourhassan said. “This is expected to significantly accelerate enrollment in the trial and allow us to test PRO 140 in a broader patient population with limited treatment options. We believe that the change will also significantly expand the potential market for PRO 140, if the trial is successful.
HIV Equal first reported in July about PRO 140 and how it could mean an end to daily pills, instead allowing the disease to be treated with two inj
|ections per week.
In September, in an exclusive interview with HIV Equal, Pourhassan said, “One FDA official told me ‘I have a room full of adolescents right now that would love this,’ and that is a direct quote. Treatment interruption is very attractive for the patient.”
He added that if the product comes to market, CytoDyn likely will be acquired by a large drug manufacturer such as Gilead. He said the company already met with a Gilead representative a while back, but at that time PRO 140 only was on track to win FDA approval for use among people who inject drugs and do not adhere to traditional regimens. That would have given the drug a much smaller market share.
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