HKU scientists find potential new HIV drug

Team develop promising vaccine to boost a type of white blood cell that can target the virus, but they say it is still at an early stage

PUBLISHED : Thursday, 16 May, 2013, 12:00am
UPDATED : Thursday, 16 May, 2013, 5:11am

Local researchers have found a new way to tackle HIV, through a vaccine that boosts the number of a white blood cell that can kill the virus.

The vaccine has been tested only on mice and may be a few years away from human trials, but the method devised by University of Hong Kong researchers was granted a US patent earlier this year.

Several hundred mice were infected with HIV for the four-year project that involved multiple studies. All the mice that were immunised lived, while the ones that weren't died.

"You could say we had a 100 per cent success rate," Professor Chen Zhiwei, director of the university's Aids Institute, said yesterday. The vaccine was delivered to the mice via an implant that released doses into the muscle.

An estimated five million people in Asia are living with the virus, according to a UNAids report in 2011.

The number of HIV patients in Hong Kong hit a 30-year high last year, with 513 new cases.

Since its emergence 30 years ago, the disease has killed millions. In 2011, 1.7 million people died from Aids-related diseases worldwide.

You could say we had a 100 per cent success rate
Professor Chen Zhiwei

Patients do not die because the body is not capable of fighting the virus, but because the body's immune system becomes weakened by HIV. The virus can be managed with medication, allowing infected patients to live to an old age. US basketball star Magic Johnson has been living with HIV for more than 20 years since he was diagnosed in 1991.

Boosting the number of a specific type of white blood cell - the T cells - that are able to target the virus has been shown to be effective in treating HIV infections.

The DNA vaccine developed at HKU boosts the T cells at a higher frequency than any other technique has previously, which could mean patients would not have to take HIV medication continually. The studies also showed how the immune system worked to regulate specific CD8+ T cell responses.

Chen, who has been working to develop a vaccine for the disease, said a clinical trial could happen in around five years.

He said he was talking to Tsinghua University and the Chinese Academy of Sciences about adding the new technique to a clinical trial that was being planned for another vaccine.

"We're looking to find people to collaborate with on this," he said "We can't do this alone."

If the researchers want to continue the trials using monkeys, they will have to look elsewhere, as the primates are not available for testing here. The HKU team are also carrying out tests to see if a similar approach could be applied to treating cancer.

Chen said he had high hopes for the vaccine and was confident about the results so far, but the study was still at an early stage and the results might not be replicated in humans. Several clinical trials and replication by other researchers would be necessary.

Michael Bartos, of UNAids, said it was at an early stage, but that "each step forward in new approaches and potential candidate vaccines is good news".

The results of the HKU team's study were published this month in the Journal of Clinical Investigation.

Meanwhile, clinical trials of another Aids vaccine in the United States costing US$77 million have been halted as there was no evidence of its efficacy in the latest round of testing.

Separately, scientists made headlines in March worldwide, describing the case of a child, then aged 21/2, who appeared to have been "cured" of the disease. The child, being cared for at the University of Mississippi, had been free of medication for about a year with no sign of the infection after treatment. "You could call this about as close to a cure, if not a cure, that we've seen," said Dr Anthony Fauci of the US National Institutes of Health, who was familiar with the findings.