Majority in SMA Community Survey Support Prenatal Treatment: Study
Highest support was among those with severe SMA — type 0 or 1
Note: This story was updated Sept. 19, 2022, to correct that 78.9% of the survey respondents would choose an ASO or a small molecule therapy, such as Evrysdi (risdiplam), if they were approved therapies.
Many members of the spinal muscular atrophy (SMA) community are interested in the possibility of treatments given during pregnancy before a baby with SMA is born, according to a new study.
Results suggest interest in prenatal treatment is particularly high among people with more severe forms of SMA.
“This is the first stakeholder survey conducted for fetal therapies for patients with SMA and offers meaningful insights into patient and parent attitudes towards emerging fetal therapies,” the researchers wrote.
The study, “Investigating Attitudes Towards Prenatal Diagnosis and Fetal Therapy for Spinal Muscular Atrophy (SMA),” was published in Prenatal Diagnosis. The work was funded by the National Institutes of Health and the University of California, San Francisco (UCSF).
Multiple disease-modifying treatments for SMA have become widely available over the last several years. These therapies can help prevent the progression of the disease, but their ability to fix damage that has already occurred is limited. Across treatments, clinical trials have consistently shown that the best outcomes are achieved when treatment is started as early as possible.
SMA is marked by the gradual death of motor neurons, the nerve cells that control movement. In many cases, motor neuron death begins during pregnancy while the fetus is still developing, meaning that even if treatment was started from the moment of birth, some damage would already have accrued.
Researchers are exploring the possibility of prenatal SMA treatment, where treatment is initiated during pregnancy for fetuses confirmed to have SMA via prenatal genetic testing.
Working with the nonprofit Cure SMA, a team led by scientists at UCSF surveyed the SMA community to better understand attitudes toward prenatal treatment.
“Having so recently witnessed the rapid proliferation of drugs that can alter the natural history of SMA, the SMA community may be predisposed to be optimistic about other novel approaches such as fetal therapies,” the researchers wrote. “As the possibility of prenatal therapies emerges, it is also important to assess whether this population’s historical interest in previous novel approaches also portends an interest in prenatal clinical trials.”
The researchers said understanding community views “can help inform conversations with regulatory authorities regarding trials for fetal therapies, and importantly, provide direction for future trials in considering their primary beneficiaries’ priorities and needs.”
Respondents favor fetal therapies
The survey was answered by 114 people: 68 patients with SMA and 46 parents of a child with SMA. The median age was 37 and most respondents were white women with a bachelor’s or graduate degree. The most common SMA type was type 2 (43.9%), followed by type 3 (29.8%), and type 1 (25.4%). One parent of a child with type 0 SMA responded.
Only two participants reported a prenatal diagnosis of SMA. Most felt there had been a delay in diagnosing the disease. About three-quarters strongly supported prenatal testing.
“Most of our respondents were strongly supportive of prenatal testing for SMA; this percentage was higher among respondents affected by more severe SMA [types],” the researchers noted. “This subset of respondents may have felt that, based on their experiences, there was more to gain from an earlier diagnosis.”
Participants were asked about their potential interest in two types of prenatal SMA treatment: a gene therapy — such as the approved treatment Zolgensma (onasemnogene abeparvovec-xioi) — or an antisense oligonucleotide (ASO), such as the approved medication Spinraza (nusinersen).
Overall, 61.1% of respondents said they would likely enroll in a clinical trial testing fetal treatment with a gene therapy, while 55% said they were likely to enroll in a trial testing an ASO.
If the hypothetical therapy were already approved, 87% said they would choose fetal treatment with a gene therapy, and 78.9% said they would choose an ASO or a small molecule therapy such as Evrysdi (risdiplam).
Generally, those affected by more severe SMA (type 1 or 0) were more likely to say they would enroll in a trial or use prenatal treatment.
“Based on their experiences, patients and caregivers affected by a more severe form of SMA in our survey may have felt that future generations would have more to gain from prenatal therapy, tipping the scale so that the benefits of prenatal therapy outweighed the risks in our theoretical scenarios,” the researchers wrote.
The scientists noted that the survey did not assess rationales for responses, highlighting a need for further research into what factors affect these decisions. They also noted that the surveyed group of mostly white people with substantial formal education “is not unusual for a survey distributed via Cure SMA, but … is not representative of all members of the SMA community.”
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