Gene therapy may be the answer for HIV

Clinical Trials Of Breakthrough Gene Therapy To Treat HIV Expected In 2012

Scientists at Calimmune, a stem cell company founded by Nobel Laureate Dr. David Baltimore, plan to start Phase I/II clinical trials of a revolutionary new gene therapy to treat HIV infections.

Narayanan Suresh 07/25/2011

About one percent of people in Europe have a rare gene mutation that makes them immune to the dreaded HIV (human immunodeficiency virus) infection that has so far killed over 30 million people globally since 1981. Scientists have identified that gene that makes them immune and using that knowledge developed a novel gene therapy to provide immunity to HIV patients.
Scientists at San Francisco-based Calimmune, founded by Nobel Laureate Dr. David Baltimore, have sought the permission of US regulator FDA (food and drugs administration) to start phase I/II clinical trials of their proprietary gene therapy that aims to remove the protein that is used by the HIV virus to infect a person.
Calimmune scientists presented the results of their studies so far and made the announcement about the clinical trials during the BIO International Convention in Washington DC on June 28,2011.
The therapy works like this. HIV infects a person using a protein CCR5 which acts as the co-receptor for the virus to invade the T cells. Most people inherit two copies of the gene, one from each parent, that codes for the CCR5 protein. However, it was discovered that about one percent of adult Europeans have a mutation in both the copies of the gene and hence do not produce the CCR5 protein. This makes them resistant to HIV infection because the virus cannot infect a person in the absence of this protein.
Nobel laureate Dr. Baltimore had suggested a decade ago that this knowledge could be used to develop gene therapies that block the protein aiding the HIV infection. Calimmune was founded in 2007 by a group of distinguished scientists and entrepreneurs which included Dr. Baltimore.
Calimmune scientists have since then pioneered a blood stem cell therapy that uses several mechanisms such as RNAi interference to block the expression of the protein CCR5.
Currently HIV infections leads to the prevalence of AIDS (acquired immunodeficiency syndrome) over a period of time and proves fatal in most of the patients. These patients are given lifelong treatment of antiretroviral drugs. The annual treatment for each patient costs about $25,000 (Rs. 11.4 lakh) or about $750,000 (Rs. 3.4 crore) on average for a patient’s life time. More than 30 million are known to have HIV infection globally now.
If the gene therapy is successful, a patient needs to be given a one-time treatment that too without any hospitalization. The patient should develop the immunity to handle the HIV infection. “This is the culmination of more than a decade of research and development, and we look forward to being able to treat patients with this powerful approach,” said Dr. Geoff Symonds, chief scientific officer of Calimmune, in a press statement released during the BIO convention. Dr. Symonds had led the world’s largest cell-derived HIV gene therapy trial during his stint with Johnson and Johnson prior to joining Calimmune.
Added Dr. Baltimore: “The scientists who started Calimmune are devoted to trying to blunt the impact of HIV infection on the world’s population. We came out of our laboratories to form a company that could have an effect on this disease. We are committed to devoting the time and energy necessary to be successful. For all of us, such an outcome would be the most gratifying event of our lives.”
Dr. Baltimore shared the 1975 Nobel Prize for Physiology or Medicine with Howard Temi and Renalto Dulbecco for the discovery of reverse transcriptase which is essential for the reproduction of retroviruses such as HIV. He is currently the chairman of the board of Calimmune and President Emeritus of California Institute of Technology (Caltech).
Genetic modification, if successful, should pave the way for a permanent cure to this dreaded disease. The currently used retroviral treatments only help to delay the infection from turning into AIDS and enhance the patient’s life by a few years. It does not provide a permanent cure.