Auspex新药SD-809治疗亨廷顿舞蹈症3期临床效果显著

Auspex新药SD-809治疗亨廷顿舞蹈症3期临床效果显著

                               
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发布日期：2014-12-21  来源：生物谷  

近日，Auspex Pharmaceuticals宣布，该公司治疗亨廷顿舞蹈症的试验药物SD-809的3期临床结果显着，与安慰剂组相比，能够降低病人发生不受控行为的发生率。

                               
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    近日，Auspex Pharmaceuticals宣布，该公司治疗亨廷顿舞蹈症的试验药物SD-809的3期临床结果显着，与安慰剂组相比，能够降低病人发生不受控行为的发生率。

SD-809是一种由老药tetrabenazine(四苯喹嗪）经化学修饰的新药，tetrabenazine(四苯喹嗪）本来就用于治疗亨廷顿舞蹈症引发的异常不自主运动。亨廷顿舞蹈症是由基因缺陷引起的严重神经退行性疾病。Tetrabenazine(四苯喹嗪）需要频繁给药，并且副作用较多，而SD-809的作用时间更长，病人的耐受度也更好。

基于这次3期临床实验以及另外一个独立研究（从tetrabenazine换到 SD-809大获成功）的阳性结果，Auspex希望SD-809能在明年中期获得FDA批准。

3期临床试验的受试者是90个患有亨廷顿舞蹈症而产生不自主运动的患者，此前他们没有接受过tetrabenazine(四苯喹嗪）的治疗。这些病人被随机分组，接受每日一至两次、为期12周的SD-809治疗，对照组使用安慰剂。主要终点计算了最大舞蹈病总分，用来评估服用SD-809和安慰剂之间患者病情的缓解情况。

据报告，服用SD-809的最大舞蹈病总分为4.4，而安慰剂组是1.9.，这2.5的差距反映了SD-809对患者生理机能和生活质量上的提升。

此外，患者对SD-809的耐受性也很好。报告说明，与tetrabenazine(四苯喹嗪）对照组相比，患者服用SD-809后镇静、困倦、失眠、焦虑和抑郁等不良反应发生的比率均较低。尽管目前两种药物并未进行直接的临床对比试验，但是Auspex希望医生能自己做出比较发现SD-809的副作用较小，从而开出更好的处方。

丹麦Lundbeck制药以Xenazine作为商品名在美国销售tetrabenazine(四苯喹嗪），据称2013年的销售额是2.53亿美元。Xenazine在美国没有专利保护，并且孤儿药专营权也将在明年结束。

Auspex凭借SD-809更好的疗效和安全性，可以避开成为trabenazine(四苯喹嗪）仿制药的名声，达到2.32亿美元的销售巅峰。对Auspex和SD-809而言，更好的商机是申请其他的治疗用途，比如迟发型运动障碍和图雷特综合症等等，如能获批，能为Auspex赢得10亿美元的销售额。此外，Auspex还面临Neurocrine Biosciences的竞争，该公司也在研发同样治疗用途的药物valbenazine。

原文 Auspex Drug Reduces Uncontrolled Movements in Huntington's Patients

An experimental drug from Auspex Pharmaceuticals (ASPX) significantly reduced the incidence of uncontrolled movements in patients with Huntington's disease compared to a placebo， according to results from a phase III study announced Tuesday.

The Auspex drug， SD-809， is a chemically modified version of an older drug， tetrabenazine， currently approved to treat chorea (abnormal involuntary movements) associated with Huntington's disease， a genetic and fatal neuro-degenerative disease. Auspex designed SD-809's effect to last longer in a patient's body and to be better tolerated than tetrabenazine， which sees limited use in Huntington's patients because of the need for frequent dosing and relatively high side effects.

Auspex is expected to seek U.S. approval for SD-809 in the middle of next year based on the positive results from the placebo-controlled phase III study plus results from a separate study in which Huntington's patients were switched successfully from tetrabenazine to SD-809.

The phase III study enrolled 90 patients suffering from involuntary movements related to their Huntington's. None of the patients had been treated with tetrabenazine previously. The patients were randomized to receive 12 weeks of treatment with SD-809 once or twice daily or a placebo. The primary endpoint measures Total Maximum Chorea Score to assess the comparable reduction in involuntary movements between SD-809 and placebo.

As reported Tuesday， patients treated with SD-809 showed a 4.4-point improvement in Total Maximum Chorea Score compared to a 1.9-point improvement for patients treated with placebo. The 2.5-point benefit favoring SD-809 was statistically significant. Key secondary efficacy endpoints measuring quality of life and physical functioning also showed a statistically significant benefit for SD-809， Auspex said.

SD-809 was well tolerated in the study. Notably， reported rates of sedation， somnolence， insomnia， anxiety and depression reported by Huntington's patients treated with SD-809 were lower than the comparable side effect profile included in the FDA-approved label for tetrabenazine. The two drugs have not been compared directly against each other in a clinical trial， but Auspex hopes treating doctors will make the comparison themselves and conclude SD-809 is better tolerated than tetrabenazine.

Denmark-based Lundbeck  (HLUKF) sells tetrabenazine in the U.S. under the brand name Xenazine and reported $253 million in sales in 2013. There are no patents protecting tetrabenazine in the U.S. and orphan drug exclusivity ends next year.

Zacks analyst Jason Napodano believes Auspex can fend off generic versions of tetrabenazine with SD-809's better tolerability and safety profile， reaching peak sales in Huntington's of $232 million. The more lucrative commercial opportunity for Auspex and SD-809 will come from developing the drug and receiving approval in other movement disorders， including tardive dyskinesia and Tourette's syndrome. Combined， the latter two indications could boost peak sales of SD-809 to more than $1 billion， projects Napodano. Auspex is also facing competition from Neurocrine Biosciences (NBIX) ， which is developing a drug， valbenazine， for the same movement disorders.