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

Research Health World General
 
  Home
 
   Health
 Aging
 Asian Health
 Events
 Fitness
 Food & Nutrition
 Happiness
 Men's Health
 Mental Health
 Occupational Health
 Parenting
 Public Health
 Sleep Hygiene
 Women's Health
 
   Healthcare
 Africa
 Australia
 Canada Healthcare
 China Healthcare
 India Healthcare
 New Zealand
 South Africa
 UK
 USA
 World Healthcare
 
   Latest Research
 Aging
 Alternative Medicine
 Anaethesia
 Biochemistry
 Biotechnology
 Cancer
 Cardiology
 Clinical Trials
 Cytology
 Dental
 Dermatology
 Embryology
 Endocrinology
 ENT
 Environment
 Epidemiology
 Gastroenterology
 Genetics
 Gynaecology
 Haematology
 Immunology
 Infectious Diseases
 Medicine
 Metabolism
 Microbiology
 Musculoskeletal
 Nephrology
 Neurosciences
 Obstetrics
 Ophthalmology
 Orthopedics
 Paediatrics
 Pathology
 Pharmacology
 Physiology
 Physiotherapy
 Psychiatry
 Radiology
 Rheumatology
 Sports Medicine
 Surgery
 Toxicology
 Urology
 
   Medical News
 Awards & Prizes
 Epidemics
 Launch
 Opinion
 Professionals
 
   Special Topics
 Ethics
 Euthanasia
 Evolution
 Feature
 Odd Medical News
 Climate
Search

Last Updated: Nov 18, 2006 - 1:55:25 PM
Breakthrough

Clinical Trials Channel
subscribe to Clinical Trials newsletter

Latest Research : Clinical Trials

   DISCUSS   |   EMAIL   |   PRINT
First human trial of recombinant ricin vaccine completed
Jan 31, 2006 - 7:54:00 PM, Reviewed by: Dr. Priya Saxena

"We have shown that this vaccine is safe and immunogenic. Now we need to tinker with the dose and formulation to give the longest-lasting and most robust immunity."

 
Scientists have completed the first human clinical trial of a recombinant vaccine for the deadly toxin ricin - a potential bioterror threat � and the results indicate the vaccine is safe and effective in eliciting ricin-neutralizing antibodies, the UT Southwestern Medical Center researchers report.

The nearly year-long pilot study involved three groups of five volunteers each. Individuals in each group received a series of three injections of various doses of the vaccine, called RiVax, over the study period. As a recombinant vaccine, RiVax is a form of ricin that consists of a genetically modified subunit of the toxin, rather than an inactivated whole toxin.

All five of the individuals in the group receiving the highest vaccine dose produced ricin-neutralizing antibodies in their blood, indicating their immune systems had responded. Four of five in the intermediate dose group produced antibodies, while one of five in the lowest dose group did so.

The human-produced antibodies were then injected along with active ricin toxin into test mice, and the mice survived.

"Our major concern in this trial was safety," said Dr. Ellen Vitetta, director of the Cancer Immunobiology Center at UT Southwestern and lead author of the study. Dr. Vitetta's work with ricin received international attention when she and a team of UT Southwestern researchers in the Cancer Immunobiology Center developed the experimental vaccine for the deadly toxin as an outgrowth of their cancer-therapy work. Dr. Vitetta, Dr. Joan Smallshaw, assistant professor in the center, and their colleagues showed in pre-clinical studies that the subunit of the ricin toxin used to make RiVax was non-toxic but retained the capacity to elicit immunity.

Ricin, which can be administered in food and water or sprayed as an aerosol, is extracted from castor beans. There is currently no approved vaccine to prevent ricin poisoning in humans, and the biological agent has a long history of use in espionage.

Participants in the study, however, reported only mild side effects that were consistent with any intramuscular vaccine injection, such as a sore arm or mild headache that might be experienced with a tetanus or a flu shot, said Dr. Robert Munford, a professor of internal medicine and a collaborator on the study.

Based on the protection they observed in the mice injected with ricin mixed with human-produced antibodies, the researchers projected that a RiVax-vaccinated human could withstand a lethal dose of injected ricin. The results from the UT Southwestern trial justify further development of the vaccine, Dr. Vitetta said.
"We have shown that this vaccine is safe and immunogenic," said Dr. Vitetta. Antibodies were present in the blood of study participants for as long as 127 days after the last vaccine injection, but the longevity of the antibodies in a given volunteer was not related to the dose level of the vaccine he or she received. Dr. Vitetta and her colleagues are now conducting studies on mice that combine the vaccine with an adjuvant, a formulation that may lengthen the time the vaccine is effective. Other common vaccines, such as tetanus, are typically administered with an adjuvant and can confer immunity for years.

Dr. Smallshaw is currently determining whether the vaccine protects against aerosol and oral administrations in mice. "In a recent series of experiments, we have shown that the vaccine protects mice against lethal doses of ricin administered orally just as well as it protects them against injected ricin," she said. Dr. Vitetta noted that, in humans, exposure by aerosol or food may require inducing immunity in the lung and gut by a very different formulation and vaccination schedule.

Because castor beans are readily available � more than 50,000 tons of castor bean extract exist around the world as a byproduct of castor oil production � public health officials warn that ricin could be used for terrorism. The CDC classifies ricin as a "Category B" biological agent, which means it is "relatively easy to disseminate."
 

- The results of the vaccine trial will be available this week online and in an upcoming issue of the Proceedings of the National Academy of Sciences.
 

www.utsouthwestern.edu

 
Subscribe to Clinical Trials Newsletter
E-mail Address:

 

Other UT Southwestern researchers from the Cancer Immunobiology Center involved in the study were Dr. John Schindler, assistant professor and director of clinical trials, and Dr. Elaine Coleman, senior research associate. Dr. Hasan Jafri, assistant professor of pediatrics, and Callie Foster, senior research nurse, also participated.

DOR BioPharma has received an exclusive license for RiVax and is developing large scale manufacturing processes. DOR officials hope to produce a large stockpile for more advanced human clinical testing, product licensing and potential purchases from the U.S. government and other interested parties.


Related Clinical Trials News
Probiotics unsafe for severe acute pancreatitis patient's due to its increased mortality.
Start of Second Phase III Trial in MS Neuropathic Pain
RISUG (Reversible Inhibition of Sperm Under Guidance) Trial to recruit more volunteers
EU clinical trials directive is threatening future of cancer research
Lessons from natalizumab fast tracking in multiple sclerosis
First human trial of recombinant ricin vaccine completed
New stem cell study seeks to prevent heart failure
Electronic health record-based clinical trial alert system increased recruitment rates
Study of New, Non-Growth Hormone Treatment for Short Stature


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