The Whitworths of Arizona, bringing science to you in everyday language.

Friday, October 17, 2014

Research Update

In April of 2013, this blog reported on some recent research projects of interest to anyone dealing with a Lewy body disorder. Here’s an update for three of those projects.

Pimavanserin. Reference. Pimavanserin (NUPLAZID), a new drug to treat Parkinson’s disease psychosis, has received Breakthrough Therapy Designation (BTD) from the FDA in September of this year. This means that the FDA agrees that the drug is intended to treat a serious or life-threatening disease and preliminary clinical evidence suggests that it provides a substantial improvement over existing therapies.

Most drugs used to manage LBD's many behavioral symptoms have been too dangerous to use safely with our loved ones. Even those, such as Seroquel, that may seem to work well for many PwLB disorders come with a serious warning. Clinical trials, now complete, demonstrated that this oral, once-a-day drug had significant antipsychotic efficacy with few side effects. The next step is to submit a New Drug Application, planned for late this year. As with the Exelon, which the FDA approved for Parkinson’s with dementia, the drug, if approved, will be equally useful for DLB, the form of Lewy body dementia which starts prior to motor difficulties.

Biomarkers: Reference. A biomarker provides objective evidence of a disease. An ideal biomarker:

  1. is objective rather than subjective. That is, it is physical evidence rather than a patient’s or caregiver’s report of symptoms or even a doctor’s evaluation.
  2. can be collected from live people, rather than from an autopsy.
  3. is easily and safely obtained. Collecting a sample for testing would not be painful, uncomfortable, expensive or dangerous.
  4. can be found early, well before symptoms of the disease appear. This gives researchers a chance to identify ways to treat the disease at a much earlier stage.
The April blog discussed finding alpha-synuclein, the precursor to Lewy bodies, in the nerves of the GI tract even five years before the development of a Lewy body disorder. More recent research explored the expediency of using colonoscopy to look for alpha-synuclein pathology in known PD patients, with the hope that it would provide live, objective biomarkers for Lewy Body disorders. However, the tests were no more than 60% successful. They aren’t very practical either: A colonoscopy may require general anesthesia, not always safe with LB disorders. It always requires preparation that can be uncomfortable.

But all is not lost. Although the research is early yet, alpha-synuclein has also been found in saliva and skin in amounts great enough to act as biomarkers. These may be more practical; access to live samples is easy and safe. It would also seem likely that it would be possible to find evidence of alpha-synuclein pathology well before any Lewy body symptoms appeared. Apparently, this aspect has yet to be explored.

Heart Imaging. Reference. Alpha-synuclein pathology has also been found in cardiac tissue. Researchers used a radioactive tracer used with heart imaging that is called 123I-metaiodobenzylguanidine (MIBG), to make a distinction between the Lewy body disorders and AD, and to predict eventual LBD even in amnestic MCI (the type that usually precedes AD). Articles about this procedure abound and it is now considered one of the tests a neurologist can use to help distinguish between AD and LBD. The next step is to discover how early alpha-synuclein pathology can be found in cardiac tissue.

More information on new research in coming weeks!

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