India Pharma Outlook Team | Friday, 03 June 2022
Even as highly effective Covid-19 vaccines have been developed in a year, the history of HIV vaccine research has been far less successful. Experts treating HIV/AIDS have called for using DNA and mRNA based Covid vaccine platforms to successfully produce HIV vaccines. It has been 38 years since HIV was first discovered as the cause of AIDS, but there is still no vaccine available against this disease. The first candidate vaccine against AIDS was made in 1987 by Dr Jonas Salk who had invented the polio vaccine.
The candidate vaccine went in phase 1 trial in 1989 but could not succeed. Till date, no preventive HIV vaccine exists, but research is underway. Only two out of 30 HIV candidate vaccines which have been tested in approximately 60 phase I/II trials, involving more than 10,000 healthy volunteers, went to phase 3 trials. So far AIDSVAX, an experimental HIV vaccine that was developed originally at Genentech in San Francisco, California, and later tested by the VaxGen company, showed partial efficacy in preventing HIV in phase 3 trials.
Another canarypox–protein HIV vaccine regimen (ALVAC-HIV plus AIDSVAX B/E) showed modest efficacy in reducing infection in Thailand in phase 2b-3 study. On the other hand, there has been a lot of progress in therapeutic vaccines or immuno-therapy to prevent disease progression to clinical stages. After the success of long-acting antiretrovirals, injectable cabotegravir plus rilpivirine is the first complete HIV treatment regimen that does not require daily pills. Vaccine research and development is a long-drawn and very expensive proposition.
With over 35 years gone in this field without any commercialized vaccines, there are very few companies and research laboratories which would invest in HIV vaccine development. After the Covid vaccine success, there are two specific Covid vaccine platforms, which can be used for HIV with success. One is mRNA and the second one is DNA. A DNA vaccine
has been produced by Zydus Cadila called ZyCov-D for Covid and that platform can also be used for HIV. But mRNA is a very successful platform, used by Pfizer and Modena and another is under development at Pune based Gennova Biopharmaceuticals and Hyderabad based Biological-E; which utilizes broadly neutralizing antibodies,” said Dr Ishwar Gilada, President, AIDS Society of India (ASI).
“Broadly neutralising antibodies (BNAbs) are produced by certain types of B immunity cells, which are rare and may be only one in 300,000 B cells that have this capability. The mRNA vaccine aims to stimulate production of bnAbs that can act against many variants of HIV. So, what this mRNA vaccine will do is instigate our B-cells and try to produce more neutralizing antibodies. And when neutralizing antibodies are produced in HIV negative people, if that person is exposed to HIV, the neutralizing antibodies will neutralize HIV and do not allow the HIV negative person to get infected,” said Dr Gilada who is also Consultant in HIV, STDs and Infectious Diseases at Mumbai based Unison Medicare & Research Centre.
Currently, India has 2.3 million people living with HIV (PLHIV). Of these 76 per cent know their HIV status and among those who know their HIV status, 84 per cent are on antiretroviral treatment (ART). Among those on ART 84 per cent were suppressed virally. New HIV infections in India have declined by 37 per cent between 2010 and 2019 compared to the global average of 23 per cent. Similarly, during the same period, AIDS-related deaths have declined in India by almost 66 per cent against the global average of 39 per cent decline, according to National AIDS Control Organization (NACO). The decline is higher in states like Andhra Pradesh, Maharashtra, Karnataka, Telangana, Tamil Nadu, and West Bengal and noticeably among women and children with 73.7 per cent and 65.3 per cent respectively.
“However, despite commendable progress, challenges continue to confront our progress to end AIDS by 2030. Mizoram (2.32 per cent), Nagaland (1.45 per cent), and Manipur (1.18 per cent) had higher than 1 per cent HIV prevalence in the adult population in 2019. HIV prevalence injection drug users is almost 28 times higher than overall adult prevalence.
Similarly, HIV prevalence among Hijra/Transgender people, men who have sex with men and female sex workers is 6 to 13 times higher than the adult prevalence. Among inmates in central jails, where the population with high-risk behaviour is over-represented, HIV prevalence is 9 times higher than the adult prevalence. More than 69,000 people were newly infected with HIV in 2019 - twice the envisaged 2020 milestone (75 per cent reductions since 2010),” he said.
, CDSCO.jpg)
