La FDA aprueba la Fase IIB de ensayos clínicos para ACR16
La dopamina es un importante neurotransmisor que juega un rol clave en la cognición, el estado de ánimo, la atención, el aprendizaje, la actividad motora, el sueño y el comportamiento, por lo que interferir con él es algo que debe ser realizado con sumo cuidado. Parece que la dopamina juega un rol en la enfermedad de Huntington. Los receptores de dopamina se reducen progresivamente con el progreso de la enfermedad. Además, hay algunas evidencias de que hay una sensibilidad anormal a la dopamina en las neuronas espinales medias afectadas por la EH.
El ACR-16 parece trabajar fortaleciendo el control cortical del ganglio basal. El cuerpo estriado, que es parte del ganglio basal, es el piloto automático del cerebro. Una vez que ya aprendimos un comportamiento, no necesitamos prestarle toda nuestra atención. El cuerpo estriado controlará la actividad mientras nuestra corteza piensa en algo más. Una vez que el cuerpo estriado comienza a degenerarse con la EH, la corteza cerebral pierde el control del ganglio basal. Por este motivo, los pacientes con la EH tienen problemas para realizar varias actividades a la vez.
Referencias:
Dr. Joakim Tedroff's talk at the 2008 HDSA convention
Wikipedia on dopamine
Charvin, D. , Vanhoutte, P., Pages, C., Borelli, E., Caboche, J. "Unraveling a role for dopamine in Huntington's disease: The dual role of reactive oxygen species and D2 receptor stimulation." Proc Natl Acad Sci U S A. 2005 Aug 23;102(34):12218-23.
Flemming Pedersen, CEO of NeuroSearch, comments: “The FDA acceptance of our IND application for ACR16 and of the protocol for the US HART study is an important milestone for NeuroSearch. With the European Phase III MermaiHD (Multinational European Multicentre ACR16 study in Huntington’s Disease) study ongoing, we now look forward to completing our international development programme for ACR16 in the treatment of Huntington’s disease. Currently, patients suffering from Huntington’s disease have very limited treatment options. Bringing this promising novel treatment concept to the market to help alleviate the burden of a serious and very disabling disease would therefore be a highly valuable step forward for both patients and their relatives, as well as for NeuroSearch as a company.”
The HART study is planned as a randomised, double-blinded and placebo controlled study expected to include 220 patients. In the study, patients will receive daily doses of either 22.5 mg (QD), 45 mg (QD) or 45 mg (BID) ACR16 or placebo to evaluate the efficacy and safety of ACR16 over three months’ treatment. The primary efficacy endpoint of this study will be the effect of ACR16 on Huntington patients’ voluntary motor function (parkinsonism, gait/balance, hand functionality, bradykinesia) measured by the modified Motor Score, mMS - a subscale of the Unified Huntington’s Disease Rating Scale (UHDRS). Secondary endpoints include the overall clinical impression of the patients, their cognitive function, neuropsychiatric symptoms such as depression and anxiety. The efficacy endpoints in the HART study are the same as in the ongoing European MermaiHD study.
ACR16 belongs to a novel class of active agents called dopaminergic stabilisers, which have the unique ability to either enhance or inhibit dopamine controlled functions depending on the initial level of dopaminergic activity. ACR16 was previously evaluated in four clinical Phase I/II studies with patients suffering from Huntington’s disease, Parkinson’s disease and psychoses, and demonstrated a good safety and tolerability profile. In a Phase II study with ACR16 in Huntington’s disease, the results showed that 28 days’ treatment with ACR16 resulted in a statistically significant improvement in the patients’ voluntary movements including parkinsonism and gait function.
Huntington’s disease is a fatal, hereditary neurodegenerative genetic disorder, which leads to damage of the nerve cells in certain areas of the brain including the basal ganglia and cerebral cortex. Patients suffering from Huntington’s disease experience a wide variety of symptoms typically grouped into three categories (the “symptoms triad”): motor, cognitive and psychiatric disorders. The motor symptoms include muscle spasms and rigidity, tics, gait and balance problems as well as chorea and in the later stage of the disease also difficulties in swallowing. The most significant cognitive symptoms are slowed processing of information in the brain, resulting in communicational and planning difficulties, while depression is the most common of the psychiatric symptoms of Huntington’s disease.
The disease occurs at a rate of about one in 10,000 in most Western countries with symptoms onset typically around 35-45 years of age. There is currently no cure or effective treatment for Huntington’s disease and the disease progresses without remission over an expected lifespan of 10 to 25 years after symptoms onset. Eventually, every person afflicted by Huntington’s disease requires full-time care.
Both the EMEA (European Medicines Agency) and the FDA have granted ACR16 orphan drug status for the treatment of Huntington’s disease.
ACR16 was discovered and is developed internally by NeuroSearch, which has the rights to develop and commercialise the compound for the treatment of Huntington’s disease in the European Union, Norway, Switzerland and North America. All other rights to the compound have been outlicensed to Astellas Pharma Inc.
