Evidence continues to accumulate on the benefits of onasemnogene abeparvovec, the first and only gene therapy (from Novartis) for spinal muscular atrophy (SMA) – a rare genetic disorder that involves degeneration of motor neurons and a progressive impairment of movement, swallowing and breathing. During clinical trials, the majority of children with type 2 AMS treated in the pre-symptomatic phase achieved motor milestones typical of the developmental age, comparable to those of healthy children, while children with type 1 AMS (the most severe form) have retained important functionalities such as swallowing and speaking.
Few or no signs of SMA 2
The Phase III SPR1NT clinical trial involved children with type 2 AMM, a form of the disease that without therapy cancels the ability to walk and stand and progressively impairs respiratory and swallowing muscle function. At less than six weeks of age, in the presymptomatic phase, 15 infants with three copies of the Smn2 gene underwent an intravenous infusion of onasemnogene abeparvovec (which can be done only once in a lifetime) to evaluate safety and efficacy. gene therapy, the aim of which is to replace the function of the missing or non-functioning SMN1 gene by stopping the progression of the disease. By 24 months of age, all children were able to stand on their own, without support for at least 3 seconds (14 managed to do so within the time window of normal development defined by the World Health Organization – WHO). Furthermore, 14 children walked independently (11 in the normal development window). Furthermore, no one needed support for breathing or feeding.
Talking, eating and drinking with Sma 1
In the phase I START and phase III clinical trials STR1VE-EU and STR1VE-US, a total of 65 children with type 1 AMM – the most severe form of AMM that typically leads to death or the need for permanent ventilation at the age of two in more than 90% of cases – received onasemnogene abeparvovec before the age of six months. A retrospective analysis of the results of the three trials made it possible to verify the benefits of gene therapy even in these small patients: at the end of the studies (24 months of age for START and 18 for STR1VE) 92% had at least one swallowing test normal and had no difficulty protecting the airways while taking food and fluids. Among the 20 children of English mother tongue, 95% were still able to communicate in an understandable way by an unknown person.
Results of notable impact that change the clinical course of the disease as it is known today, commented experts such as Kevin Strauss, Medical Director of the Clinic for Special Children in Pennsylvania, underlining how “these data clearly demonstrate the value of newborn screening for SMA. , which is essential in order to provide children with the earliest diagnosis and treatment, in order to guarantee them the best possible results “.