The HART clinical trial testing ACR16 in Huntington's began in October 2008 with its first participant. And as is usual, it has taken additional time to open all of the centers needed for this 220 person trial. But now with 17 centers actively recruiting, many participants are still needed to complete enrollment for this important trial. Overall, the HD community response to recruitment has been less than overwhelming. Why aren't we signing up in larger numbers? Why should we bother?

There is a straightforward answer: There will never be new treatments if we don't join clinical trials.

What is ACR16? ACR16 is a new drug that took more than twenty years of basic research in Dr. Arvid Carlsson's laboratory in Sweden, followed by another 10 years of drug development. That is thirty years and millions of dollars of work before reaching clinical trials for Huntington's. The ACR16 (Arvid Carlsson Research 16) drug "modulates" the action of dopamine, a very important chemical that is involved in Huntington brain damage. In HD there is excessive action of dopamine in some areas of the brain, while there is too little action in others. Unlike other dopamine drugs on the market, ACR16 is designed to provide dual beneficial actions: to increase dopamine action in areas of the brain where it is low, and to decrease it in other areas where it is too high.

Has ACR16 been Tried in People? There is prior use of this drug in Europe. Fifty eight people participated in a 4 week Phase 2 trial with results reported in May 2006. In this study: there was no appreciable difference in side effects between placebo or ACR16. Those who received active drug showed improved motor function, particularly chorea (involuntary movements), gait and speech. ACR16 also reduced akinesia (slowness of movements). There was also a strong trend towards reduction of symptoms of anxiety and depression in ACR16 treated patients and a marked improvement in performing the Trail Making test, a test for cognitive function.

The Phase 3 trial of ACR16 (MermaHD) is already in progress in Europe.

What about ACR16 (HART) in North America? What is required of participants?

How many visits? Seven visits (which includes the first assessment) over 14 weeks. That seems like a lot of visits, but three of these will be short (about 1 hour) for blood, urine and Electrocardiogram (EKG) testing. Why so many visits? Because the FDA requires frequent and careful checks for safety on this, and every new experimental drug.

What are My Chances of Getting ACR16? Three different doses of ACR-16 will be compared to placebo. You will have a greater chance of receiving active drug than placebo in this trial.

What about Other Medications? Because the trial will measure motor benefit you will not be able to take Xenazine® (tetrabenazine), or any neuroleptic (drugs like Zyprexa® and Risperdal®). There will also be restrictions on certain antidepressants (probably Wellbutrin®) though others will be permitted.

Why choose this trial? Though there are several visits, this 3-month trial will give results fairly quickly. And though it is an experimental drug, there is already a small, but documented level of safety and suggested broad benefit from European study.

For more complete HART description and criteria and participating sites visit

Editor Comments: Industry is watching: At least so far in Huntington's history it has taken longer to find patients for a clinical trial than to complete it. As example, the recent 3-month long Dimebon trial took more than 9 months to find the 90 people needed. And it is looking like ACR16 will take even longer. Why does this additional time matter? In addition to slowing down getting new drugs to HD people, this protracted time adds millions of dollars of cost to drug companies. You can be sure that industry is watching -- and that more drug companies will be interested in working on drugs for HD when we become a more active partner by efficiently entering clinical trials.

How you can help clinical trial efforts:

  • Become aware of clinical trials.
  • Sign up at
  • Educate yourself -- and share what you learn with others in support groups and extended families.
  • Join the clinical trial that best fits your circumstances. It may seem scary at first, but the vast majority of those who participate are glad they did.
  • Encourage and help others to participate.

You can -- and must -- help these efforts if we are to get new treatments for Huntington's.