Patients with Stable Disease Who Switch to Another Interferon Therapy at Greater Risk of Flares, Study Reports

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by Ana Pena PhD |

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Multiple sclerosis (MS) patients who have been relapse-free while using an interferon-beta (IFN-β) therapy but switch to another IFN-β are significantly more like to start experiencing flares than patients who remain on their initial interferon treatment, a real-world study reports.

Its results support letting patients remain on a current IFN-β medication if that therapy is keeping their disease stable, and may help guide treatment decisions and insurance-covered medication lists, researchers say.

The study, “Multiple sclerosis patients who are stable on interferon therapy show better outcomes when staying on same therapy than patients who switch to another interferon” was published in the journal ClinicoEconomics and Outcomes Research.

Currently in the U.S., four IFN-β injectable therapies are available to treat relapsing forms of MS: under the skin (subcutaneous) injections of IFN-β-1b (Betaferon/Betaseron, marketed by Bayer; Extavia, marketed by Novartis), intramuscular injections of IFN-β-1a (Avonex, sold by Biogen), under the skin IFN-β-1a (Rebif, marketed by EMD Serono), and under the skin peginterferon β-1a (Plegridy, sold by Biogen).

All have comparable efficacy and safety, the study notes, and continuous use of these therapies can benefit an RRMS patient’s outcomes by reducing the number and frequency of flares and possibly delaying disease progression.

Patients may move to an alternative disease-modifying therapy (DMT) or a different IFN-β for a number of reasons that include failing to respond optimally to an initial therapy, personal preferences (e.g., due to the mode of administration or adverse reactions), or because of disease progression. Increasingly, changes in the medications covered by an insurance plan also drive some to switch therapies.

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A team led by researchers at Biogen and the University of Florida conducted a study to compare outcomes among stable MS patients who remained on their initial IFN-β therapy with those who switched to a different IFN-β treatment.

This type of investigation “may help guide treatment decisions and formulary decision-makers,” the researchers wrote.

Data on a group of MS patients, ages 18 to 64, were collected from the claims database of OptumInsight, a commercial managed care health insurance, between Jan. 1, 2005, and Sept. 30, 2014. A total of 381 patients were in the “switch” group, and 1,143 in the “no switch” group. Patients were matched for age, gender, initial IFN-β therapy and treatment adherence. Those on Plegridy, approved in 2014, were excluded due to lack of available data.

All patients had been relapse-free (defined as clinically stable disease) for more than one year while on continuous treatment with an IFN-β therapy. Relapses were recorded during a one-year follow-up period for both patient groups. Relapses were defined in the claims data as any inpatient hospital stay or outpatient visit requiring treatment with corticosteroids, adrenocorticotropic hormone, or total plasma exchange.

Data showed that a significantly higher percentage of patients who had switched to a different IFN-β therapy experienced a relapse during that year than in those who remained on the same treatment — 21.3% versus 11.7%, respectively.

Annual relapse rates were also greater in the “switch” group — 0.35 relapses per patient year — than among “no switch” patients — 0.20 relapses per patient year.

These data reflect a 45% lower chance of experiencing a relapse, and a 43% lower annual relapse rate in patients who remained on the same IFN-β therapy, compared to those who switched.

In a sub-group analysis, looking only at patients initially treated with Avonex (the only intramuscular injection assessed), results followed the same trend. Of those who switched from Avonex, 23.22% experienced a relapse in the following year, compared to 10.99% of those who stayed on Avonex. And the annual relapse rate was twice as high in the group who switched (0.40 versus 0.20).

Overall, the data “supports the benefits of allowing patients to remain on current IFN-β therapy when stable,” the researchers wrote, adding that further studies are needed to better understand when to switch therapies or stay on an initial therapy.

This study was sponsored by Biogen, and two of its three authors are listed as Biogen employees.

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