XML Feed for RxPG News   Add RxPG News Headlines to My Yahoo!   Javascript Syndication for RxPG News

Research Health World General
 
  Home
 
 Latest Research
 Cancer
 Psychiatry
 Genetics
 Surgery
 Aging
 Ophthalmology
 Gynaecology
 Neurosciences
 Pharmacology
 Cardiology
 Obstetrics
 Infectious Diseases
  AIDS
  Influenza
  MRSA
  Tuberculosis
  Shigella
  HCV
  SARS
  Ebola
  Dengue
  Malaria
  Pertussis
  Mumps
  Prion Diseases
  Small Pox
  Anthrax
  Leishmaniasis
 Respiratory Medicine
 Pathology
 Endocrinology
 Immunology
 Nephrology
 Gastroenterology
 Biotechnology
 Radiology
 Dermatology
 Microbiology
 Haematology
 Dental
 ENT
 Environment
 Embryology
 Orthopedics
 Metabolism
 Anaethesia
 Paediatrics
 Public Health
 Urology
 Musculoskeletal
 Clinical Trials
 Physiology
 Biochemistry
 Cytology
 Traumatology
 Rheumatology
 
 Medical News
 Health
 Opinion
 Healthcare
 Professionals
 Launch
 Awards & Prizes
 
 Careers
 Medical
 Nursing
 Dental
 
 Special Topics
 Euthanasia
 Ethics
 Evolution
 Odd Medical News
 Feature
 
 World News
 Tsunami
 Epidemics
 Climate
 Business
Search

Last Updated: Nov 7th, 2006 - 22:20:17

AIDS Channel
subscribe to AIDS newsletter

Latest Research : Infectious Diseases : AIDS

   DISCUSS   |   EMAIL   |   PRINT
Fighting HIV With HIV Virus Itself
Nov 7, 2006, 22:12, Reviewed by: Dr. Priya Saxena

Overall, the study results are significant, say the researchers, because it is the first demonstration of safety in humans for a lentiviral vector (of which HIV is an example) for any disease.

 
Researchers at the University of Pennsylvania School of Medicine report the first clinical test of a new gene therapy based on a disabled AIDS virus carrying genetic material that inhibits HIV replication. For the first application of the new vector five subjects with chronic HIV infection who had failed to respond to at least two antiretroviral regimens were given a single infusion of their own immune cells that had been genetically modified for HIV resistance.

The researchers, led by Carl June, MD, and Bruce Levine, PhD, of the Abramson Family Cancer Research Institute and the Department of Pathology and Laboratory Medicine, along with Rob Roy MacGregor, MD, Professor of Medicine, report their findings in the online edition of the Proceedings of the National Academy of Sciences. Viral loads of the patients remained stable or decreased during the study, and one subject showed a sustained decrease in viral load. T-cell counts remained steady or increased in four patients during the nine-month trial. Additionally, in four patients, immune function specific to HIV improved.

Overall, the study results are significant, say the researchers, because it is the first demonstration of safety in humans for a lentiviral vector (of which HIV is an example) for any disease. Additionally, the vector, called VRX496, produced encouraging results in some patients where other treatments have failed.

“The goal of this phase I trial was safety and feasibility and the results established that,” says June. “But the results also hint at something much more.”

Each patient received one infusion of his or her own gene-modified T cells. The target dose was 10 billion cells, which is about 2 to 10 percent of the number of T cells in an average person. The T-cell count was unchanged early after the infusions. “We were able to detect the gene-modified cells for months, and in one or two patients, a year or more later,” says Levine. “That’s significant – showing that these cells just don’t die inside the patient. The really interesting part of the study came when we saw a significant decrease in viral load in two patients, and in one patient, a very dramatic decrease.

But, cautions Levine, “just because this has produced encouraging results in one or two patients doesn’t mean it will work for everyone. We have much more work to do.” In the current study, each patient will be followed for 15 years.

“The new vector is a lab-modified HIV that has been disabled to allow it to function as a Trojan horse, carrying a gene that prevents new infectious HIV from being produced,” says Levine. “Essentially, the vector puts a wrench in the HIV replication process.” Instead of chemical- or protein-based HIV replication blockers, this approach is genetic and uses a disabled AIDS virus to carry an anti-HIV genetic payload. The modified AIDS virus is added to immune cells that have been removed from the patients’ blood by apheresis, purified, genetically modified, and expanded by a process June and Levine developed. The modified immune cells are then returned to the patients’ body by simple intravenous infusion.

This approach enables patients’ own T cells, which are targets for HIV, to inhibit HIV replication – via the HIV vector and its anti-viral cargo. The HIV vector delivers an antisense RNA molecule that is the mirror image of an HIV gene called envelope to the T cells. When the modified T cells are given back to the patient, the antisense gene is permanently integrated into the cellular DNA. When the virus starts to replicate inside the host cell, the antisense gene prevents translation of the full-length HIV envelope gene, thereby shutting down HIV replication by preventing it from making essential building blocks for progeny virus. VRX496 was designed and produced by the Gaithersburg, Md. biotech company VIRxSYS Corp.

The new vector is based on a lentivirus, a subgroup of the well-known retroviruses. The study and its safety profile to date have now opened up the field of lentiviral vectors, which have potential advantages over other viral vectors currently being studied because they infect T cells better than adenoviruses, a commonly used viral vector. Lentiviruses also infect non-dividing or slowly dividing cells, which improves delivery to cells such as neurons or stem cells, thus enabling the evaluation of gene therapy in an even wider array of diseases than before. Furthermore, lentiviral vectors insert into cellular DNA in such a way that may be safer than other gene therapy vectors. This is because lentiviruses appear to insert differently from other retroviruses that have caused side effects in other trials involving stem-cell therapy. In addition, gene insertion by lentiviral vectors is attractive for potential therapeutics since it enables long-term gene expression, unlike other viral vectors where expression is lost over time.

Penn researchers are now recruiting for a second trial using the VRX496 vector with HIV patients whose virus is well controlled by existing anti-retroviral drugs, a group of patients who are generally healthier and have more treatment options available. This trial will use six infusions rather than one and is designed to evaluate the safety of multiple infusions and to test the effect of infusions on the patients’ ability to control HIV after removal of their anti-retroviral drugs. The hope is that this treatment approach may ultimately allow patients to stay off antiretroviral drugs for an extensive period, which are known to have significant toxicity, especially after long-term use.
 

- Proceedings of the National Academy of Sciences
 

www.med.upenn.edu/research/penn

 
Subscribe to AIDS Newsletter
E-mail Address:

 

The research was supported by the National Institute of Allergy and Infectious Disease; the Abramson Family Cancer Research Institute; and VIRxSYS Corp. In addition to June, Levine, and MacGregor, co-authors on the paper are: Jean Boyer and Frederic Bushman from Penn; Laurent M. Humeau, Tessio Rebello, Xiaobin Lu (now with US Pharmacopeia), Gwendolyn K. Binder (now with Penn), Vladimir Slepushkin, Frank Lemiale, and Boro Dropulic (now with Lentigen Corp, Baltmore) from VIRxSYS; and John R. Mascola from the National Institutes of Health.

PENN Medicine is a $2.9 billion enterprise dedicated to the related missions of medical education, biomedical research, and high-quality patient care. PENN Medicine consists of the University of Pennsylvania School of Medicine (founded in 1765 as the nation's first medical school) and the University of Pennsylvania Health System.

Penn's School of Medicine is ranked #2 in the nation for receipt of NIH research funds; and ranked #3 in the nation in U.S. News & World Report's most recent ranking of top research-oriented medical schools. Supporting 1,400 fulltime faculty and 700 students, the School of Medicine is recognized worldwide for its superior education and training of the next generation of physician-scientists and leaders of academic medicine.
The University of Pennsylvania Health System includes three hospitals, all of which have received numerous national patient-care honors [Hospital of the University of Pennsylvania; Pennsylvania Hospital, the nation's first hospital; and Penn Presbyterian Medical Center]; a faculty practice plan; a primary-care provider network; two multispecialty satellite facilities; and home care and hospice.


Related AIDS News

Keeping A3G in action represents a new way to attack HIV
Fighting HIV With HIV Virus Itself
HIV exploits competition among T-cells
Harmless GB Virus type C (GBV-C) protects against HIV infection
Study defines effective microbicide design for HIV/AIDS prevention
HIV depends on human p75, study shows
Simplified treatment of HIV infection shows promise
Clinical trial evaluates first-line approaches for treating HIV
T cells activated to fight HIV basis for dendritic cell therapeutic vaccine
B cells with special protein direct HIV to T cells


For any corrections of factual information, to contact the editors or to send any medical news or health news press releases, use feedback form

Top of Page

 

© Copyright 2004 onwards by RxPG Medical Solutions Private Limited
Contact Us