SOUTH PLAINFIELD, N.J., May 7, 2019 /PRNewswire/ — PTC Therapeutics, Inc. (NASDAQ: PTCT) today announced clinical data from the studies of FIREFISH and SUNFISH demonstrating the benefit of risdiplam (RG7916) for the treatment of Type 1, 2 and 3 spinal muscular atrophy (SMA). Patients across all studies continue to achieve motor milestones relative to natural history. Risdiplam has been well tolerated at all doses across studies; there have been no drug related safety findings leading to withdrawal. Regulatory submissions based on Part 1 of FIREFISH and SUNFISH are planned in the second half of 2019. The data from these pivotal trials were presented at the 2019 American Academy of Neurology Annual Meeting in Philadelphia. The SMA program is a collaboration between PTC, the SMA Foundation, and Roche.
"The magnitude of the benefit observed in all SMA types in both trials is very compelling," said Stuart W. Peltz, Ph.D., Chief Executive Officer of PTC Therapeutics. "We believe the improvements seen in developmental milestones across patients with Type 1, 2 and 3 SMA, and the positive safety profile of risdiplam, an oral therapy, will support a compelling submission package for the FDA and the EMA."
In Part 1 of the FIREFISH study, at 12 months of treatment, among the infants who received the dose selected for the confirmatory Part 2 of the study, (n=17), 7 (41.2%) were able to sit without support for at least 5 seconds, assessed by the Gross Motor Scale of the Bayley Scales of Infant and Toddler Development – Third Edition (BSID-III). In addition, 11 (64.7%) infants were able to sit (with or without support) while 9 (52.9%) achieved upright head control after 12 months of treatment as assessed by the Hammersmith Infant Neurological Examination Module 2 (HINE-2). Finally, 1 infant (5.9%) achieved the milestone of standing (supports weight) by this 12-month time point. These results demonstrate a clear divergence from natural history where babies with Type 1 SMA never achieve these milestones. No baby has required tracheostomy, reached permanent ventilation or lost the ability to swallow. At 12 months, 18/19 babies were able to feed orally (exclusively or in combination with a feeding tube). 85.7% of babies remain alive with three having discontinued due to the fatal progression of their disease.
Part 1 of SUNFISH includes a broad patient population aged 2-25 years with Type 2 or 3 SMA and with baseline functional status ranging from individuals unable to sit to those capable of walking. Scoliosis ranged from none to severe. An exploratory efficacy analysis of Part 1 of the SUNFISH study assessed motor function, using the Motor Function Measure-32 (MFM32) scale. The results demonstrate that among the patients for which the MFM32 test has been completed at all visits up to month 12 (n=43), 58% saw an improvement of at least 3 points on the scale from baseline, compared to 7.6% for a matched natural history cohort (n=39). The change from baseline in total MFM32 score is the primary efficacy endpoint in the ongoing Part 2 of the trial. In addition, a sustained median increase from baseline in SMN protein of greater than two-fold, as measured in blood, was seen after 12 months of treatment with risdiplam.
Risdiplam is an investigational small molecule SMN2 splicing modifier targeting the survival motor neuron 2 (SMN2) RNA, restoring a functional transcript. In preclinical studies, risdiplam given orally, crossed the blood brain barrier, and showed systemic distribution to all organs and tissues.
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SOURCE PTC Therapeutics, Inc.