Tysabri Side Effects

6 ADVERSE REACTIONS The following serious adverse reactions are described below and elsewhere in the labeling: Progressive Multifocal Leukoencephalopathy (PML) [see Warnings and Precautions ( 5.1 )] Herpes Infections [see Warnings and Precautions ( 5.3 )] Hepatotoxicity [see Warnings and Precautions ( 5.4 )] Hypersensitivity/Antibody Formation [see Warnings and Precautions ( 5.5 )] Immunosuppression/Infections [see Warnings and Precautions ( 5.6 )] Hematological Abnormalities [see Warnings and Precautions ( 5.8 )] Most common adverse reactions (incidence ≥ 10%): MS - headache, fatigue, arthralgia, urinary tract infection, lower respiratory tract infection, gastroenteritis, vaginitis, depression, pain in extremity, abdominal discomfort, diarrhea NOS, and rash ( 6.1 ) CD - headache, upper respiratory tract infections, nausea, and fatigue ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Biogen at 1-800-456-2255 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch .

6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.

The most common adverse reactions (incidence ≥ 10%) were headache and fatigue in both the multiple sclerosis (MS) and Crohn's disease (CD) studies.

Other common adverse reactions (incidence ≥ 10%) in the MS population were arthralgia, urinary tract infection, lower respiratory tract infection, gastroenteritis, vaginitis, depression, pain in extremity, abdominal discomfort, diarrhea NOS, and rash.

Other common adverse reactions (incidence ≥ 10%) in the CD population were upper respiratory tract infections and nausea.

The most frequently reported adverse reactions resulting in clinical intervention (i.e., discontinuation of TYSABRI) in the MS studies were urticaria (1%) and other hypersensitivity reactions (1%), and in the CD studies (Studies CD1 and CD2) were the exacerbation of Crohn's disease (4.2%) and acute hypersensitivity reactions (1.5%) [ see Warnings and Precautions ( 5.5 ) ].

A total of 1617 multiple sclerosis patients in controlled studies received TYSABRI, with a median duration of exposure of 28 months.

A total of 1563 patients received TYSABRI in all CD studies for a median exposure of 5 months;

of these patients, 33% (n=518) received at least one year of treatment and 19% (n=297) received at least two years of treatment.

Multiple Sclerosis Clinical Studies The most common serious adverse reactions in Study MS1 [ see Clinical Studies ( 14.1 ) ] with TYSABRI were infections (3.2% versus 2.6% in placebo, including urinary tract infection [0.8% versus 0.3%] and pneumonia [0.6% versus 0%]), acute hypersensitivity reactions (1.1% versus 0.3%, including anaphylaxis/anaphylactoid reaction [0.8% versus 0%]), depression (1.0% versus 1.0%, including suicidal ideation or attempt [0.6% versus 0.3%]), and cholelithiasis (1.0% versus 0.3%).