Genentech presents pivotal FIREFISH and SUNFISH Studies in Spinal Muscular Atrophy
Genentech, a member of the Roche Group announced new data from the dose-finding Part 1 of the pivotal FIREFISH trial showing infants with Type 1 spinal muscular atrophy (SMA) achieved key motor milestones after one year of treatment with investigational risdiplam. Among the infants who received the dose selected for the confirmatory Part 2 of the study (n=17), seven (41.2 percent) 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 percent) infants were able to sit (with or without support) while nine (52.9 percent) achieved upright head control after 12 months of treatment as assessed by the Hammersmith Infant Neurological Examination Module 2 (HINE-2). Finally, one infant (5.9 percent) achieved the milestone of standing (supports weight) by this 12-month time point. The data were presented at the 71st American Academy of Neurology (AAN) Annual Meeting from May 4-10 in Philadelphia, Pennsylvania. Roche and Genentech lead the clinical development of risdiplam, an investigational, orally administered survival motor neuron-2 (SMN2) splicing modifier for SMA, as part of a collaboration with the SMA Foundation and PTC Therapeutics.
Part 1 of FIREFISH also assessed motor function with the Children’s Hospital of Philadelphia Infant Test of Neuromuscular Disorders (CHOP-INTEND), a scale used for infants with Type 1 SMA. Results showed that 10 out of 17 infants (58.8 percent) in the therapeutically dosed group achieved a CHOP-INTEND total score of 40 points or more. Median change from baseline to month 12 in CHOP-INTEND was 17.5 points. The maximum CHOP-INTEND score was 57 points after 12 months of treatment, increasing from a maximum of 49 points after eight months.
Among all 21 infants enrolled in Part 1 of the FIREFISH study, the median duration of treatment is 14.8 months, with 19 infants treated for more than 12 months. Three infants experienced fatal complications of their disease after approximately one, eight and 13 months of treatment. None of these have been attributed by the investigator as related to risdiplam. No infant has lost the ability to swallow during the study, and no infant has required tracheostomy or permanent ventilation. The event-free survival was 18 out of 21 (85.7 percent) overall and 15 out of 17 (88.2 percent) in the therapeutically dosed group. The most common adverse events included fever (pyrexia; 52.4 percent), upper respiratory tract infections (42.9 percent), diarrhea (28.6 percent), vomiting (23.8 percent), cough (23.8 percent), pneumonia (19.0 percent) and constipation (19.0 percent).
Genentech also presented new data from Part 1 of its pivotal SUNFISH trial in people aged 2-25 years with Type 2 or 3 SMA. The dose-finding SUNFISH Part 1 includes a particularly broad patient population. Baseline functional status ranged from individuals unable to sit to those capable of walking. Scoliosis ranged from none to severe. As previously reported, 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. The most common adverse events in Part 1 of the SUNFISH study were fever (pyrexia; 41 percent), cough (33 percent), vomiting (29 percent), upper respiratory tract infections (26 percent), persistent sore throat (oropharyngeal pain; 22 percent) and cold (nasopharyngitis; 20 percent). The most common serious adverse event that occurred in two of the 51 patients exposed to risdiplam was pneumonia. To date there have been no treatment-related safety findings leading to withdrawal from any study.
An exploratory efficacy analysis of Part 1 (n=51) of the SUNFISH study assessed motor function, using the Motor Function Measure-32 (MFM32) scale. This scale is designed to detect motor function changes in a broad range of patients, from weak Type 2 to strong Type 3 SMA, and is therefore more appropriate for the SUNFISH population. One patient withdrew from the trial during the open-label extension. Among the patients for which the MFM32 scale has been completed at all visits up to month 12 (n=43), 58 percent saw an improvement of at least three points on the scale from baseline, including 71 percent among patients 2-11 years old and 42 percent aged 12-25 years. While Part 1 of the SUNFISH study was not designed or powered to detect efficacy, the change from baseline in total MFM32 score is the primary efficacy endpoint in the ongoing Part 2 (n=180) of the trial. The confirmatory Part 2 portions of the SUNFISH and FIREFISH studies have completed enrollment and will conduct their primary efficacy analyses in Q4 2019 and Q1 2020, respectively.
Roche and Genentech lead the clinical development of risdiplam as part of a collaboration with the SMA Foundation and PTC Therapeutics. Risdiplam is currently being evaluated in four multicenter trials in people with SMA
FIREFISH (NCT02913482) – an open-label, two-part seamless pivotal clinical trial in infants with Type 1 SMA. Part 1 was a dose-escalation study in 21 infants. The primary objective of Part 1 was to assess the safety profile of risdiplam in infants and determine the dose for Part 2. Per protocol, four infants enrolled (“Cohort A”) were required to remain at their low dose for over 12 months in order to evaluate longer term safety at multiple doses. The remaining patients (“Cohort B”; n=17) were allowed by the protocol to more quickly escalate to the expected therapeutic dose selected in Part 2. Part 2 is a pivotal, single-arm study of risdiplam in 41 infants with Type 1 SMA for 24 months, followed by an open-label extension. Enrollment for Part 2 was completed in November 2018. The primary objective of Part 2 is to assess efficacy as measured by the proportion of infants sitting without support after 12 months of treatment, as assessed in the Gross Motor Scale of the Bayley Scales of Infant and Toddler Development – Third Edition (BSID-III) (defined as sitting without support for 5 seconds). Part 2 is ongoing.
SUNFISH (NCT02908685) – a two-part, double-blind, placebo-controlled pivotal clinical trial in children and young adults (2-25 years old) with Type 2 or 3 SMA. Part 1 determined the dose for the confirmatory Part 2. The primary objective of Part 2 is to evaluate motor function using total score of Motor Function Measure 32 (MFM32) at 12 months. Enrollment for Part 2 was completed in September 2018 with 180 patients randomized and the study is ongoing.
JEWELFISH (NCT03032172) – an open-label exploratory trial in people with all types of SMA aged 6 months-60 years who have been previously treated with SMN-targeting therapy or olesoxime. The study is currently recruiting.
RAINBOWFISH (NCT03779334) – a new trial in pre-symptomatic SMA initiated earlier this year.
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