• People who start taking Spinraza (nusinersen) to treat spinal muscular atrophy (SMA) may not always stick with the treatment.
• The way the drug is administered and a person’s underlying health conditions can complicate the treatment schedule.
• Those who did not stick with Spinraza treatment often had increased health care expenses and spent more days in care than those who did stick with it.

Spinraza is intended as a lifelong treatment for SMA. However, less than 50 percent of people continue taking the drug within two years, according to a recent study. A significant number of people also do not stick to the prescribed schedule for receiving the drug, the study found. People who strayed from the treatment plan had poorer health outcomes and faced higher health care costs.

For the study, research company Symphony Health used previously collected data to determine how often people stuck to their treatment schedule and the consequences of discontinuing treatment.

Spinraza Treatment for SMA

Spinraza was approved by the U.S. Food and Drug Administration (FDA) in 2016 as the first medication for treating both children and adults with SMA. It contains small pieces of genetic material that bind to ribonucleic acids (RNA) in cells, allowing the RNA to be used to make functional proteins. This is important because faulty survival motor neuron (SMN) genes cannot properly make SMN proteins, which leads to the development of SMA.

Spinraza contains genetic material, so it cannot be given orally: If taken that way, the medication would be broken down in the stomach. Instead, the medication is given as an intrathecal injection directly into the fluid surrounding the spinal cord. Researchers are investigating new methods to administer the drug more easily, including an implanted catheter.

Treatment begins with four loading doses, which are given within the first two months of treatment. Once these are complete, maintenance doses are given every four months for the rest of the person’s life. Administration requires a doctor’s appointment for each injection.

The treatment schedule for Spiraza must be strictly followed in order for the medication to work.

The schedule can be even more difficult for young children — who may have multiple complications — and their parents to stick to. With this in mind, the researchers investigated how well those who take Spinraza adhere to the schedule and the impact it has on health care.

Spinraza Use Decreases Over Time

The researchers used health care data previously collected from Symphony Health’s Integrated Dataverse to identify people with SMA who took Spinraza starting Dec. 23, 2016 through Nov. 20, 2019. Overall, they identified 23 people had SMA type 1, 41 had SMA type 2, and 260 had SMA type 3. The researchers then followed the data on these people until Spinraza treatment was stopped or the data no longer included information about treatment.

The percentages of those who adhered to the regular Spinraza treatment schedule for all the doses they received were roughly the same for each type of SMA:

• 71.8 percent for type 1
• 74.4 percent for type 2
• 75.6 percent for type 3

Those who had trouble sticking with the schedule had other underlying health problems, such as breathing complications, difficulty eating, and muscle weakness.

Over time, the number of people who continued Spinraza treatment decreased. The analysis revealed that less than 50 percent of those taking the drug — regardless of SMA type — remained on the treatment 24 months after starting.

The median time from start to discontinuation was:

• 18.5 months in people with SMA type 1
• 6.2 months in people with SMA type 2
• 14.4 months in people with SMA type 3

Overall, people with SMA who did not stick to the treatment schedule for Spinraza required more health care resources and spent more time in care than those who did stick to it. Health care costs also increased for those who discontinued Spinraza treatment across all SMA types compared to those who continued treatment.

Learn more about the economic costs of SMA.

Logistics and Poor Communication May Contribute To Lack of Adherence

Researchers identified several reasons people may be unable to adhere to the drug regimen. Some were logistical, including being unable to find care for siblings and securing transportation to appointments. Others related to lack of knowledge about the treatment, fear of adverse effects, and poor communication with health care providers.

The study authors recommended steps health care providers could take to help people stick with their treatment plan. “Strategies to improve adherence include quickly detecting non-adherence (e.g., missed appointments) as well as identifying barriers to adherence,” researchers concluded. “Patient and family education on the importance of adherence is also critical.”

Limitations of the Study

It is important to remember that all scientific studies have their limitations. The data used was previously collected, which limits the conclusions that researchers can draw. The number of people used in the study was small, and more studies will be needed to confirm these findings. The data used in the study was also collected before the COVID-19 pandemic, so any impact the pandemic may have had was not reflected in the data.