MS Drug Gilenya May Increase Risk of Lymphopenia
Studies in Sweden and Germany indicate that underweight women with multiple sclerosis who take the MS drug Gilenya (fingolimod) seem to be at increased risk for lymphopenia. The drug also poses a risk for patients who have low lymphocyte levels before they start drug treatment.
Lymphopenia (also known as lymphocytopenia) is a condition in which a person has a deficiency (penia) of lymphocytes, which are a subset of white blood cells (leukocytes). Lymphocytes, which can be T cells, B cells, or natural killer cells, play a crucial role in supporting immune system function.
It’s been known that fingolimod can lower the level of circulating lymphocytes. In fact, among the serious side effects reported by the Food and Drug Administration (FDA) and the drug’s manufacturer, Novartis Pharma Stein AG, is infections.
Risk of infections is increased because the drug lowers lymphocyte levels. The two newly reported studies cast new light on some of the factors associated with this risk.
In the German study, 418 individuals with relapsing-remitting multiple sclerosis were enrolled in an open label study in which they took 0.5 mg of fingolimod daily. Blood samples were collected on four separate occasions: immediately before treatment and at months 1, 4, and 6. In the Swedish study, data from 438 patients were used to validate the findings.
Here are some of the findings:
- Women who had a body mass index (BMI) less than 18.5 kg/m2 had a 26 percent increased risk for developing lymphopenia (counts at or lower than 0.2 x 109/L associated with drug use. This effect was not seen in men with this BMI.
- Individuals whose starting lymphocyte levels were less than 1.6 x 109/L had a 46 percent increased risk of lymphopenia while using the drug
- Use of glatiramer acetate (Copaxone) before use of Gilenya seemed to help protect against the development of lymphopenia, although the researchers were uncertain about the immunologic effect of this drug
Prior research (phase III trials) has indicated that the decline in lymphocyte counts among MS patients who take fingolimod is not associated with meal timing or the use of other medications, such as corticosteroids.
The findings of the two new studies provide doctors with additional information to consider when Gilenya is on the treatment table, such as monitoring of female patients who are underweight and/or individuals who have low baseline lymphocyte counts. Other serious side effects that may develop with use of Gilenya include slow heart rate (bradycardia), which can occur when starting treatment; macular edema, which typically appears after three to four months of treatment; liver problems; and shortness of breath.