Isis Pharmaceuticals Initiates Phase I/IIa Study of ISIS_HTTRx For Huntington’s Disease

Ana de Barros, PhD avatar

by Ana de Barros, PhD |

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Huntington's disease therapy

Isis Pharmaceuticals, Inc. a leading company in RNA-targeted drug discovery and development, recently announced they will initiate a new Phase I/IIa clinical trial of ISIS_HTTRx for the treatment of Huntington’s disease (HD). Roche will give Isis a milestone payment of $22 million for the initiation of the trial.

The placebo-controlled, randomized, dose-escalation clinical trial will assess the clinical activity and safety of ISIS-HTTRx in patients with early stage of HD. ISIS-HTTRx will be given to HD patients intrathecally through an injection directly into the cerebral spinal fluid.

This trial will assess the first drug candidate considered as a potential treatment for HD, which can reduce the production of all forms of huntingtin gene protein, a toxic protein underlying HD.

ISIS-HTTRx is an antisense drug designed to correct the genetic defect that causes HD, an inherited genetic brain disorder that results in the progressive loss of both mental faculties and physical control. This malignancy is caused by the expansion of the CAG trinucleotide sequence in the huntingtin (HTT) gene. The resulting mutant HTT protein is considered toxic and gradually damages neurons. Symptoms usually appear between the ages of 30 and 50, and worsen over a 10 to 25 year period. Ultimately, the weakened patient succumbs to pneumonia, heart failure or other complications. Presently, there is no effective treatment or cure for the disease, and current available medicines only mask patients’ symptoms but do not slow down the underlying loss of neurons.

The company is developing the drug in a partnership with Roche. The agreement intends to develop antisense drugs for the treatment of HD. Isis Pharma has received an upfrount and milestone payment of $52 million for the development of ISIS-HTTRx and will receive additional payments upon the continuous drug development process (plus royalties on sales upon commercialization).

The drug currently holds an orphan drug status in the European Union for the treatment of HD. The European Medicines Agency (EMA) awards orphan drug status to drugs that are being developed for the treatment of rare, debilitating and life threatening conditions that affect no more than 5 in 10,000 people in the European Union.