Ionis Pharmaceuticals, Inc. announced that the US Food and Drug Administration has granted Orphan Drug designation to IONIS-HTTRx for the treatment of patients with Huntington's disease (HD). IONIS-HTTRx is the first therapy to enter clinical development that is designed to directly target the cause of the disease by reducing the production of the protein responsible for HD.

IONIS-HTTRx has also been granted orphan drug designation by the European Medicines Agency for the treatment of patients with HD.

"HD is a rare genetic neurological disease in which patients experience deterioration of both mental abilities and physical control. Although the toxic protein produced from the huntingtin (HTT) gene in HD patients has been a target of interest for many years, IONIS-HTTRx is the first therapy to enter clinical development that is designed to treat the underlying cause of this fatal disease. The granting of Orphan Drug designation in both the US and Europe highlights the significant need for a drug that could transform the treatment of HD," said C. Frank Bennett, Ph.D., senior vice president of research at Ionis Pharmaceuticals.

The Orphan Drug Act provides for economic incentives to encourage the development of drugs for diseases affecting fewer than 200,000 people in the United States. Orphan drug designation entitles seven years of market exclusivity in the United States if market approval is granted for IONIS-HTTRx for the treatment of patients with HD. Additional incentives include tax credits related to clinical trial expenses, an exemption from the FDA-user fee, and FDA assistance in clinical trial design.

Roche and Ionis are collaborating to develop antisense drugs to treat HD. The alliance combines Ionis' antisense expertise with Roche's scientific knowledge in developing neurodegenerative therapeutics. To date, Ionis has earned $52 million in upfront and milestone payments from its relationship with Roche and is eligible to earn additional milestone payments as the drug progresses in development, as well as royalties on sales of IONIS-HTTRx if it is commercialised. Roche has the option to license IONIS-HTTRx from Ionis through the completion of the phase 1/2a study. Prior to option exercise, Ionis is responsible for the discovery and development of IONIS-HTTRx. If Roche exercises its option, it will assume responsibility for global development, regulatory and commercialisation activities for the drug.

CHDI Foundation, Inc. provided financial and scientific support to Ionis' HD drug discovery programme through a development collaboration with Ionis. Over time, CHDI will be reimbursed for its support of Ionis' program out of milestone payments received by Ionis.

IONIS-HTTRx is a Gen. 2.0+ antisense drug in development 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.

HD is a rare genetic, progressive neurological disease resulting in deterioration in mental abilities and physical control. HD is referred to as a triplet repeat disorder, and is one of a large family of genetic diseases in which certain gene sequences are mistakenly repeated. In HD, the gene that encodes for the HTT protein contains a trinucleotide sequence that is repeated in the gene more than 36 times. The resulting HTT protein is toxic and gradually damages neurons in the brain. Symptoms of HD usually appear between the ages of 30 to 50 years, and continually worsen over a 10 to 25 year period. Ultimately, the weakened individual succumbs to pneumonia, heart failure or other complications. Presently, there is no effective disease modifying treatment, and current approaches only focus on managing the severity of some disease symptoms.