Experts Foresee Approval of Three New Drugs for Huntington’s Disease By 2023
Survey identifies lack of disease-modifying therapies as critical unmet need
Decision Resources Group, a health care research firm located in Burlington, Mass., finds that three therapies — pridopidine (Huntexil, Teva); cysteamine bitartrate (Procysbi, Raptor); and the tetrabenazine analogue SD-809 (Auspex) — will likely receive regulatory approval for Huntington’s disease (HD) in the U.S. during the 2013–2023 study period. Notably, all three drugs are expected to be used primarily to control and relieve motor symptoms.
“We expect Huntexil to launch before SD-809 and Procysbi in the U.S. and European markets, and to have good efficacy and tolerability,” said analyst Jing Wu, MS, MBA. “Teva will likely be able to leverage its long-established presence in the neurological diseases space to quickly drive uptake of Huntexil, which we expect will capture a greater patient share than the other two new therapies by 2023.”
Despite the high unmet need for disease-modifying therapies in HD, such as gene therapies, none is expected to enter the market during the study period, owing to the considerable challenges of modulating gene expression in the human brain.
“HD is caused by mutations in a single gene and hence represents an ideal disorder to target with gene therapy,” Jing said. “However, there are currently no available technologies to deliver and sustainably modulate gene expression in the brain neurons, and this critical challenge needs to be overcome before we see gene therapies developed for the treatment of HD.”
Interviewed experts indicated awareness of the development of ISIS-HTTRX (Isis Pharmaceuticals), an antisense oligonucleotide currently in preclinical studies, but acknowledged that serious barriers remain before this approach could provide real benefits to their patients.
Because the unmet need in HD is so severe, regulators are likely to quickly approve a disease-modifying therapy offering even a modest reduction in disease progression, the survey found. Interviewed neurologists agreed that they would quickly embrace any therapy offering measurable improvements in loss of brain volume and/or a reduction in cognitive impairment.
Driven by an aging population, the number of diagnosed prevalent cases of HD in the U.S. and Europe is expected to increase by approximately 8% through 2023, the report notes.
Interviewed experts agreed that antipsychotic drugs offer meaningful behavioral and hyperkinetic movement benefits for many of their HD patients. Physicians reported that common adverse effects associated with antipyschotics, such as weight gain, sedation, and extrapyramidal symptoms, can be beneficial in HD patients who struggle to maintain weight, to achieve adequate rest, and to control movements.
The survey findings also indicate that high levels of off-label prescribing of antipsychotic drugs and antidepressants will likely continue throughout the study period as no emerging therapies appear to offer significant behavioral or mood benefits at this time.
Source: Decision Resources Group; June 12, 2014.