A vaccine designed to re-educate the immune system has been shown to be safe and feasible in the treatment of rheumatoid arthritis, according to research presented this week at the American College of Rheumatology Annual Scientific Meeting in Chicago.
Rheumatoid arthritis is a chronic disease that causes pain, stiffness, swelling, and limitation in the motion and function of multiple joints. Though joints are the principal body parts affected by RA, inflammation can develop in other organs as well. An estimated 1.3 million Americans have RA, and the disease typically affects women twice as often as men.
"RA is caused by an aberrant response that can be triggered by disease-specific antigens, or proteins," says lead investigator Ranjeny Thomas, MBBS MD; professor of rheumatology at The University of Queensland Diamantina Institute. "Current treatments attempt to reduce the joint destruction associated with this disease by targeting the inflammation that is a consequence of this immune response. However, non-specific suppression of inflammation may increase infection, and drugs may be toxic to vital organs."
Dr. Thomas' team recently completed a study looking at the feasibility and safety of using a vaccine, called Rheumavax®, to reduce the way a person's immune system reacts towards the disease antigens thought to cause RA.
"Approximately 70 to 80 percent of RA patients make antibodies towards RA-specific antigens called citrullinated peptides, which are identifiable with a blood test," explains Dr. Thomas. "While antigen-specific immune tolerance is a major goal for RA prevention and treatment, early trials failed to show a response, and the strategy was abandoned when biologic therapy was spectacularly successful. We reasoned the problem might be solved if the dendritic cells that normally educate the immune system towards these antigens were modified with a drug that would promote immune tolerance."
And, with that thought in mind, Dr. Thomas' team designed Rheumavax using drug-modified dendritic cells (generated from a person's own blood) and citrullinated peptide antigens, to suppress specific RA immune reactivity (or restore immune tolerance) - leaving broader immunity towards infections intact.
Once the vaccine was developed, the researchers identified 29 people with RA (predominately female with an average age of 56) who had suffered from the disease for an average of 5.5 years, and who were treated with at least one disease modifying anti-rheumatic drug (commonly called DMARDs).
These participants were placed into three groups. The first group of nine received 1 million Rheumavax dendritic cells, the second group of nine received 5 million, and the third (the control group) of 11 received their usual DMARDS. The cells were given once, through an injection into the thigh.
Participants were evaluated monthly for six months, and the researchers looked for safety issues, immune tolerance and changes in RA activity.
Overall, Rheumavax was well tolerated at both dosages and did not cause any skin reactions, allergic reactions, infections, or immediate disease flares. Some side effects were noted, but were all minor. These included headache, anemia, decrease in white blood cells, and altered liver function tests.
Additionally, the researchers found that those participants with lower levels of disease activity before receiving Rheumavax continued to have low disease activity, and improvements occurred after receiving Rheumavax in patients who started with higher levels of disease activity. Participants receiving Rheumavax also had improvements in blood inflammatory markers and glucose tolerance.
"This study shows that a new approach to re-educate the immune system towards RA-specific antigens using dendritic cells can be safe, says Dr. Thomas. "Similar strategies could now be developed and tested for RA prevention and treatment using this concept."