Ionis Antisense Oligonuleotide Drug IONIS-HTTRX is Safe and Decreases Levels of Toxic Huntington’s Disease Protein in Cerebrospinal Fluid.

In a statement released today, Ionis Pharmaceuticals announced study results demonstrating for the first time that their drug (IONIS-HTTRX) lowered levels of the abnormal protein causing Huntington’s disease in cerebrospinal fluid, and that this approach was safe and well tolerated in humans.



The IONIS-HTTRx Study:

The IONIS-HTTRX trial enrolled 46 patients with early Huntington’s disease at 9 study centres in the UK, Germany and Canada.  The first subject in the study was enrolled and received intrathecal infusion of study drug in September of 2015 at the Centre for Huntington Disease (CHD) The CHD is a tertiary referral centre/clinic for Huntington’s disease at The University of British Columbia in Vancouver, Canada. CMMT Professor Blair Leavitt, Director of Research at the CHD, treated all the Canadian participants for this study. “This is a very exciting day for patients and families affected by this devastating genetic brain disorder. For the first time we have evidence that a treatment can decrease levels of the toxic disease-causing protein in patients” Professor Blair R. Leavitt, Director of the CHD and UBC site investigator of the IONIS-HTTRX study. The study global chief investigator is Professor Sarah Tabrizi (UCL Institute of Neurology) and the study is sponsored by Ionis Pharmaceuticals.


As reported today, IONIS-HTTRX produced significant, dose-dependent decreases in the levels of mutant huntingtin in the cerebrospinal fluid. This is the first time the toxic protein that causes Huntington’s disease has been lowered in the central nervous system of patients. For all subjects who completed this study, Ionis announced in June that they would be offered a place in an open-label extension study of IONIS-HTTRX. The current study results demonstrated that this therapeutic approach has an excellent safety and tolerability profile, and as a result of these findings, Roche, has exercised its option to license IONIS-HTTRX moving forward. Roche will now take responsibility for further development of this drug.

“The results of this trial are of ground-breaking importance for Huntington’s disease patients and families. For the first time a drug has lowered the level of the toxic disease-causing protein in the nervous system, and the drug was safe and well-tolerated. The key now is to move quickly to a larger trial to test whether the drug slows disease progression.” Professor Tabrizi, Director of the UCL Huntington’s Disease Centre and IONIS-HTTRX Global Chief Investigator


About Huntington’s Disease

Huntington’s disease is a fatal genetic neurological disease. It usually develops in adulthood and causes abnormal involuntary movements, psychiatric symptoms and dementia. Approximately 1 in 10,000 people in Canada have HD and for each affected individual there are 5 people at risk of the disease. To date, no effective treatments have been proven to slow down progression of this disorder. HD is caused by a single known genetic mutation, and each child of a carrier of the mutation has a 50% chance of inheriting the disease.



IONIS-HTTRx is an antisense oligonucleotide drug developed for the treatment of Huntington’s disease. IONIS-HTTRx is designed to reduce the production of all forms of the huntingtin (HTT) protein, which is the protein responsible for HD. As such, IONIS-HTTRx offers a unique approach to treat all patients with HD.

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