Gilenya Linked to Slightly Increased Cancer Risk in MS, Swedish Study Suggests

The risk of invasive cancer may be slightly higher in multiple sclerosis (MS) patients treated with Gilenya (fingolimod) compared with those treated with rituximab, and with people from the general population, a Swedish study suggests.

The study, “Cancer Risk for Fingolimod, Natalizumab, and Rituximab in MS Patients,” was published in the journal Annals of Neurology.

Disease-modifying therapies (DMTs) have revolutionized how MS disease is managed. The first DMTs, including interferon-beta (sold as Avonex and Rebif, among others), or glatiramer acetate (sold as Copaxone and its generic Glatopa) were introduced more than two decades ago.

Since then, newer and more effective DMTs have been launched. These include Gilenya, marketed by Novartis; Tysabri (natalizumab) by Biogen; and Roche’s rituximab, sold under the brand name Rituxan in the U.S. and MabThera in Europe. Of note, rituximab, an approved treatment for various types of blood cancer, is used as an off-label therapy in MS.

In Sweden, Gilenya, Tysabri, and rituximab are the most used DMTs both for initial stages and more aggressive forms of MS. However, unlike older therapies, studies on the long-term safety profile for newer DMTs are missing.

Thus, researchers in Sweden compared the risk of cancer in a large population of MS patients treated with rituximab, Gilenya, or Tysabri.

The team analyzed data from the Swedish nationwide MS registry, which contains information on MS therapies used, and crossed it with data from the Swedish Cancer Register, as well as other national healthcare and census registers. The data were collected between 2011 and 2017.

In total, the analysis included 6,136 MS patients with 7,477 treatment initiations — 4,187 for rituximab, 1,620 for Gilenya, and 1,670 for Tysabri. As controls, they included 37,801 people without MS from the general population, matched for age, sex, and location.

Among them, the researchers identified 78 invasive cancers among treated MS patients — 33 in those receiving rituximab, 28 for Gilenya, and 17 in the Tysabri group.

The most common cancers in this MS group were breast cancer, melanoma, cancers of the colon, endocrine glands and tissues, non-melanoma skin cancers, and prostate cancer.

In order to normalize the variation between treatment groups regarding certain parameters — making it easier to compare data — the team used a specific statistical method. They adjusted for demographic parameters, including age, and previous cancer and comorbidities, which is when more than one disease is present in the same person at the same time.

The team found that, compared with the general population, the risk for invasive cancer was higher in those treated with Gilenya, but similar or lower in the Tysabri and rituximab-treated groups.

Nonetheless, the team emphasized that this slight higher risk of invasive cancer in MS patients treated with Gilenya should be validated in a larger group of patients, and with longer follow-up periods. 

“In this first large comparative study of 3 highly effective MS disease‐modifying therapies, no increased risk of invasive cancer was seen with rituximab and natalizumab [Tysabri], compared to the general population. However, there was a borderline‐significant increased risk with fingolimod [Gilenya], compared to both the general population and rituximab,” the team concluded.

“It was not possible to attribute this increased risk to any specific type of cancer, and further studies are warranted to validate these findings,” the researchers added.