Dystonia and Spasticity Patients May Become Immune to Toxin Treatment
People with dystonia or spasticity can get relief from botulinum toxin type A, but a new study published online in Neurology shows that 15% of people treated with the toxin can develop an immune response to the treatment, making it less effective or ineffective.
The study involved 596 people who had received the toxin for 3 to 5 years for cervical dystonia, blepharospasm, facial hemispasm, or other types of dystonia and spasticity. The patients were responding to the treatment, but 14% had developed neutralizing antibodies that can reduce responsiveness to the toxin.
Of the 64 patients who had cervical dystonia,16% had developed the antibodies. Of the 54 people with blepharospasm, 6% had the antibodies. Of the 52 people with other types of dystonia including Meige syndrome, which affects the jaw, tongue, and eyes, 17% had the antibodies, and of the 33 people with spasticity, 15% had the antibodies.
The researchers found that the number of antibodies increased over time and the main factor for developing them was the dose of the toxin—patients who received doses above 700 units were more likely to develop the antibodies.
“People may be able to lessen their chances of developing this response by making sure the dose of the drug in each injection is as low as possible, the time between injections is not shortened, and booster injections are avoided,” said study author Philipp Albrecht, MD, of Heinrich Heine University in Düsseldorf, Germany.