Spark Therapeutics (ONCE) Trading of Stock Halted as FDA Advisory Committee Reviews Investigational Gene Therapy
The U.S. Food and Drug Administration’s (
The advisory committee meeting is scheduled to start at
Today’s advisory committee vote will be non-binding, but
Clinical Trial Overview of LUXTURNA™ (voretigene neparvovec)
The safety and efficacy of LUXTURNA were assessed in two open-label Phase 1 trials, which continue to follow participants who received LUXTURNA between 2007 and 2012, and one open-label, randomized, controlled Phase 3 trial. The LUXTURNA clinical program overall includes up to four years of efficacy data from a single dose. The overall safety profile has not changed over the period of observation, and has been previously reported (The Lancet 2016; The Lancet 2017).
Following the one-year control period of the Phase 3 study, all control participants elected to cross over and received LUXTURNA; long-term safety and efficacy continue to be assessed in the Phase 3 participants who received LUXTURNA between 2013 and 2015. The clinical trial program included 41 participants with vision loss ranging from mild to advanced, and included individuals from age four to 44 years at the time of first administration. Confirmed biallelic RPE65 mutations and the presence of sufficient viable retinal cells were established in all participants.
LUXTURNA Phase 3 clinical trial data, including data from the intent-to-treat population of all randomized participants through the one-year time point, were published in The Lancet. Results included in the BLA submission showed a statistically significant and clinically meaningful difference between intervention (n=21) and control participants (n=10) at one year, per the clinical trial’s primary endpoint, mean bilateral multi-luminance mobility testing (MLMT) score change (difference of 1.6; 95% CI, 0.72, 2.41; p=0.001). In addition, participants who received LUXTURNA showed a marked difference compared to control participants across the first two secondary endpoints: full-field light sensitivity threshold (FST) testing averaged over both eyes (p=0.001) and the mobility test score change for the first injected eye (p=0.001). A third secondary endpoint, the change in visual acuity (VA) averaged over both eyes, was not statistically significant between intervention and control participants (p=0.17).
On average, participants in the original Phase 3 intervention group maintained functional gains observed by the day-30 visit through their last annual follow-up visit, as measured by MLMT and FST, with observation ongoing. Average improvement in FST testing observed in the original intervention group at one year was more than 100-fold (or greater than two log units).
In continuation of the trial to include crossover of the control group to receive LUXTURNA, 93 percent (27 of 29) of all treated Phase 3 trial participants saw a gain of functional vision as assessed by bilateral MLMT over the follow-up period of at least one year from administration of LUXTURNA to each eye. Additionally, 72 percent (21 of 29) of all Phase 3 trial participants receiving LUXTURNA successfully completed MLMT at the lowest light level evaluated (1 lux) at one year.
Data from a cohort of the Phase 1 clinical trial, in which investigational LUXTURNA was administered to the contralateral, or second previously uninjected eye, showed mean improvements in functional vision and visual function. This cohort of participants (n=11) received the same dose of LUXTURNA that was administered in the Phase 3 trial and would have met the Phase 3 eligibility criteria. See the publication of the three-year Phase 1 data in The Lancet.
Two ocular SAEs were reported in the clinical program. There was one SAE related to the surgical procedure in one eye of a Phase 3 participant, in which there was foveal thinning and a sustained reduction in VA. One additional ocular SAE was reported in one eye of a Phase 1 participant in which the treatment for bacterial endophthalmitis led to elevated intraocular pressure and subsequent optic atrophy. There were three non-serious AEs of retinal deposits (subretinal precipitate) in three participants (three eyes) that were considered to be related to LUXTURNA. All three of these events were mild in intensity, transient in nature and resolved without consequences. No deleterious immune responses have been observed. The most common adverse reactions related to LUXTURNA reported in 10 percent or greater of the combined Phase 1 and Phase 3 trial participants included conjunctival hyperemia, cataract, increased intraocular pressure and retinal tear.
About RPE65-mediated Inherited Retinal Disease (IRD)
Inherited retinal diseases (also known as inherited retinal dystrophies) are a group of rare blinding conditions caused by one of more than 220 different genes. People living with IRD due to biallelic RPE65 gene mutations often experience night blindness (nyctalopia) due to decreased light sensitivity in childhood or early adulthood and involuntary back-and-forth eye movements (nystagmus). As the disease progresses, individuals may experience loss in their peripheral vision, developing tunnel vision, and eventually, they may lose their central vision as well, resulting in total blindness. Independent navigation becomes severely limited, and vision-dependent activities of daily living are impaired. There are currently no approved pharmacologic treatment options for IRD due to biallelic RPE65 gene mutations.
About Gene Therapy
Gene therapy is an investigational approach to treat or prevent genetic disease by seeking to augment, replace or suppress one or more mutated genes with functional copies. It addresses the root cause of an inherited disease by enabling the body to produce a protein or proteins necessary to restore health or to stop making a harmful protein or proteins, with the potential of bringing back function in the diseased cells and slowing disease progression. To deliver the functional gene into the cell, a vector is used to transport the desired gene and is delivered either intravenously (IV) or injected into specific tissue. The goal is to enable, through the one-time administration of gene therapy, a lasting therapeutic effect.
Cautionary note on forward-looking statements
This release contains "forward-looking statements" within the meaning of the Private Securities Litigation Reform Act of 1995, including statements regarding the company's product candidate LUXTURNA™ (voretigene neparvovec). Any forward-looking statements are based on management's current expectations of future events and are subject to a number of risks and uncertainties that could cause actual results to differ materially and adversely from those set forth in, or implied by, such forward-looking statements. These risks and uncertainties include, but are not limited to, the risk that: (i) our BLA or MAA submitted for LUXTURNA may not be approved by the
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Source: Spark Therapeutics, Inc.