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May 11, 2007

AAN Meeting Report

Here is a summary of news about amyotrophic lateral sclerosis (ALS, or Lou Gehrig’s disease) reported at the American Academy of Neurology 59th Annual Meeting, April 28-May 4 in Boston.

Many of the findings resulted from MDA research funding and/or the contributions of MDA clinic physicians.

MINOCYCLINE INEFFECTIVE FOR ALS

Disappointing results of a nine-month trial of the drug minocycline were announced.

Minocycline demonstrated no beneficial effect, and for some patients, worsened measurable outcomes.

People with ALS who are currently taking the drug, an antibiotic in the tetracycline family, are urged to contact their physician to discuss discontinuing its use, said MDA Medical Director Valerie Cwik, who attended the meeting.

The drug did not affect survival or quality of life measures for people with ALS in the trial.

The trial tested minocycline versus a placebo (inert, look-alike substance) in 412 people at 31 U.S. centers. The drug was thought to reduce inflammation and counteract cell death

MORE ALS FINDINGS

  • Variations in a gene for a protein called progranulin can modify the course of ALS according to a study of 230 people with ALS and 436 without the disease in Belgium. This finding could have implications for understanding and treatment of ALS.

  • Administering a compound called SOD1 antisense directly into the brains of rats destined to develop a genetic form of ALS slowed the progression of the disease early in its course and extended survival. If the drug was given prior to the onset of the disease, the increase in survival was 30 days; but if treatment was started close to disease onset, survival increased by 10 days. SOD1 antisense blocks genetic instructions for the SOD1 protein. In this form of ALS, these instructions are abnormal and lead to production of a highly toxic, disease-causing protein. Plans to test this treatment in people with SOD1-caused ALS are under way.

  • An analysis of muscle tissue in 33 people with ALS, ALS with dementia or dementia alone, seven people with various other neuromuscular disorders, and 12 people without a neuromuscular disorder showed that a protein in muscle called Nogo-A was found in 20 out of 23 (87 percent) of the ALS patients. It was also found in five out of five people with ALS and dementia (100 percent) and three out of five with dementia alone (60 percent). None of the other 19 study participants, who had another neuromuscular disease or no neuromuscular disease, had this protein in their muscle tissue. The significance of these results isn’t yet clear.

  • In a second study about Nogo_A, researchers reported that detection of this protein in muscle tissue may be a way to identify ALS very early in the course of the disease, when the diagnosis is still uncertain. Further studies are necessary to determine whether Nogo-A may be a potential biomarker for ALS.

  • A comparison of the DNA in all genes of 276 Americans and 277 Italians with ALS and 2,130 Americans and Italians without the disease has been completed. Two genetic variants that may increase the risk for developing sporadic ALS were identified in the Italian cohort but not in the US cohort of individuals with ALS. These results may yield new clues for understanding the causes of and biochemical pathways involved in sporadic ALS.

  • Variations in the genes for two enzymes, known as PON1 and PON3, appear to be risk factors for ALS, according to a study of 221 Irish ALS patients and 202 healthy subject of similar age, gender and ethnic background. These PON genes, which have previously been implicated in other ALS studies, are involved in detoxification of pesticides and other chemical compounds.

  • A study of 65 people with ALS and their primary caregivers (who were separately interviewed) found that the diagnostic phase of ALS is a time of moderate to high anxiety levels for patients, but that these tend to decrease as the disease progresses. Anxiety in caregivers, however, did not decrease with disease progression.

  • Mutations in a gene for the SOD1 protein, known to cause a type of familial ALS, don’t do so by damaging muscle tissue, a new study shows. Increasing muscle mass and strength did not slow the onset or progression of ALS in mice with the SOD1 form of the disease, although enhanced muscle mass led to temporary strength gains.

  • Phrenic nerve conduction studies are a useful tool in evaluating whether the respiratory status of paralyzed patients will benefit from implantation of electrodes that stimulate the diaphragm. The phrenic nerve normally controls diaphragm movement. This type of “diaphragm pacemaker implantation” strategy is being tested in people with spinal cord injuries and ALS.

  • Mice with a genetic form of ALS because of a mutation in the gene for the SOD1 protein responded well to a compound called anti-SOD1 siRNA, designed to block erroneous SOD1 genetic instructions. Mice bred to produce this anti-SOD1 compound and also bred to have an SOD1 mutation didn’t develop ALS symptoms until they were 280 days old, whereas all the animals with an SOD1 mutation without it died by 160 days.

  • A 20-week trial of sodium phenylbutyrate in 40 people with ALS at eight centers showed the drug was safe and tolerable for the majority of participants at dosages between 12 and 21 grams per day.

  • Cells called microglia taken from the nervous systems of mice with ALS caused by mutated SOD1 genes are more toxic when active than are microglia taken from healthy mice. Microglia are the cells that carry out an immune response in the nervous system. The study supports the hypothesis that activated microglia play a role in ALS.