Results of North Star Ambulatory Assessments (NSAA) in the Phase 3 Ataluren Confirmatory Trial in Patients with Nonsense Mutation Duchenne Muscular Dystrophy (ACT DMD) | DuchenneXchange

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Abstracts & Posters

Results of North Star Ambulatory Assessments (NSAA) in the Phase 3 Ataluren Confirmatory Trial in Patients with Nonsense Mutation Duchenne Muscular Dystrophy (ACT DMD)

key information

source: American Academy of Neurology

year: 2016

authors: Katharine Bushby, Jan Kirschner, Xiaohui Luo, Gary Elfring, Hans Kroger, Peter Riebling, Tuyen Ong, Robert Spiegel, Stuart W. Peltz, Francesco Muntoni

summary/abstract:

Objective:
Examine the efficacy of ataluren in patients with nonsense mutation Duchenne muscular dystrophy (nmDMD) as assessed by the NSAA.

Background:
Results of the Phase 3, randomized, double-blind, placebo-controlled ACT DMD trial have been reported. The NSAA is a validated functional scale to measure disease progression specifically in ambulant boys with DMD.

Design/Methods:
ACT DMD enrolled males aged 7-16 years with nmDMD and baseline six-minute walk distance (6MWD) > = 150m and < = 80%-predicted. Eligible patients were randomized 1:1 to receive ataluren 10, 10, 20 mg/kg or placebo orally three times daily for 48 weeks. A subgroup analysis of patients with baseline 6MWD of 300-400m was pre-specified. The NSAA consists of 17 activities ranging from standing from a chair to jumping. Each activity is scored as 0, 1, or 2; the sum of these 17 scores forms the total score, which is linearized to a 0 (worst)-100 (best) score.

Results:
The intent-to-treat population of ACT DMD consisted of 228 patients (ataluren, n=114; placebo, n=114). Overall, patients who received ataluren gained a 1.5-point advantage in NSAA observed score compared with patients who received placebo (mean NSAA scores, ataluren: -7.0; placebo: -8.5; p=0.270). In the pre-specified subgroup of 99 patients with baseline 6MWD 300-400m, the advantage conferred by ataluren over placebo increased to 4.5 points (mean observed NSAA scores, ataluren: -5.7; placebo: -10.2; p=0.030).

Conclusions:
Ataluren is the first drug to demonstrate a benefit to patients with nmDMD compared with placebo as assessed by NSAA scores; this benefit was especially pronounced in the subgroup of patients with baseline 6MWD 300-400m. NSAA results when combined with 6MWD results, provide complementary information on different aspects of motor function in nmDMD patients and further demonstrate the efficacy of ataluren in this patient population. More detailed analysis of NSAA domains will be presented.

organisation: Newcastle University; PTC Therapeutics

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