MS patients prefer Tysabri injection to intravenous infusion: Study

Subcutaneous treatment is 'widely accepted and preferred alternative'

Marisa Wexler, MS avatar

by Marisa Wexler, MS |

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A person lies on a gurney while being given an IV infusion.

People with multiple sclerosis (MS) who are being treated with Tysabri (natalizumab) tend to prefer receiving the medication as a subcutaneous (under-the-skin) injection rather than an intravenous (into-the-vein) infusion, according to new data from an observational study.

“Based on current data, there is a trend toward patients’ preference for the natalizumab SC [subcutaneous] route over the IV [intravenous] route, which provides valuable insights into patients’ preference for [Tysabri route of administration] in routine care,” researchers wrote.

The study, “Real-world evidence and patient preference for subcutaneous versus intravenous natalizumab in the treatment of relapsing-remitting multiple sclerosis – initial results from the observational SISTER study,” was published in Therapeutic Advances in Neurological Disorders.

Tysabri is an antibody-based medication that works to prevent inflammatory immune cells from moving into the brain and causing damage. It’s approved in the U.S. as a treatment for all relapsing forms of MS. In Europe and many other countries, it’s specifically authorized for relapsing-remitting MS (RRMS).

Tysabri is available in the U.S. and elsewhere as an intravenous infusion. A subcutaneous version of the medication was approved in the European Union in 2021, though U.S. authorities rejected an application seeking approval of the subcutaneous formulation that same year.

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‘Shared decision-making’ is key to care

Biogen, the company that markets Tysabri, is sponsoring an observational trial called the SISTER study (NCT05304520) with the aim of evaluating patient preferences regarding the two formulations. The study is open to patients starting on either formulation of Tysabri as part of standard MS care, and is taking place at multiple centers in Germany and Austria.

“Shared decision-making with patients seems to be the key to optimum care for MS patients,” the researchers wrote.

“It is anticipated that the use of SC natalizumab [meets] the users’ expectations and might further improve patients’ adherence to therapy, which is an important prerequisite for treatment success in the long term,” they wrote.

The scientists reported outcomes from the first 262 participants in the SISTER trial. About two-thirds of them had been on intravenous Tysabri but chose to switch to the subcutaneous version once it became available in 2021. Among the remaining patients, half chose to start on subcutaneous Tysabri, while the other half started on intravenous treatment.

Almost all patients starting on Tysabri were administered the treatment once every four weeks, while many of those who’d been on the therapy previously received less frequent, personalized dosing schedules. As of data cutoff in early 2023, these patients had been followed for an average of about eight months.

Upon entering the study, most patients expressed a preference for the administration route they’d chosen to receive.

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Preferences shift over time

Patients receiving intravenous Tysabri frequently reported feeling this route of administration was more comfortable, whereas patients receiving the therapy subcutaneously often said they liked it because it saved time. The average total time to administer treatment — including preparation, administration itself, and required follow-up monitoring — was about one hour with the subcutaneous injection, versus three hours with the intravenous infusion.

Over the course of follow-up, most patients continued to report a preference for the type of treatment they initially chose to receive. But the researchers noted that more patients who had started on intravenous Tysabri expressed dissatisfaction with that method as time went on.

“These data indicate a trend toward the preferred use of SC natalizumab also among patients who were initially treated with IV natalizumab,” the researchers wrote, though they stressed that longer follow-up will be necessary to see if that trend holds. Further data from the study are expected toward the end of 2024.

Efficacy outcomes with both formulations of Tysabri were similar. Only a handful of patients experienced relapses during the trial, and few saw worsening disability over one year. Safety-related outcomes generally were also comparable, though reactions at the injection site, such as pain or redness, were reported in 7.6% of patients receiving the subcutaneous formulation.

Reports from healthcare providers involved in the SISTER study have generally been favorable towards both formulation of Tysabri, though many providers report that the subcutaneous version is less complicated to administer and less time-consuming.

Overall, the findings indicate that subcutaneous Tysabri is “a widely accepted and preferred alternative” to the intravenous infusion version of the drug, the researchers wrote.