6 ADVERSE REACTIONS The following serious adverse reactions are described in detail in other sections of the labeling: Thrombocytopenia and Coagulation Abnormalities [see Warnings and Precautions (5.1)] Renal Toxicity [see Warnings and Precautions (5.2)] The most common adverse reactions that occurred in at least 20% of SPINRAZA-treated patients and occurred at least 5% more frequently than in control patients were lower respiratory infection, upper respiratory infection, and constipation (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 SPINRAZA cannot be directly compared to rates in clinical trials of other drugs and may not reflect the rates observed in practice. The data described below reflect exposure to SPINRAZA in 173 patients (50% male, 82% Caucasian), including 120 exposed for at least 6 months and 83 exposed for at least 1 year. The safety of SPINRAZA was studied in infants with symptomatic SMA, approximately 1 month to 8 months of age at study entry; in a sham-controlled trial (n=80 for SPINRAZA, n=41 for control); in open-label studies in presymptomatic and symptomatic infants (n=37), and in open-label studies in later onset patients (n=56, 2 to 15 years of age at study entry). In the controlled study in symptomatic infants, 41 patients were exposed for at least 6 months and 19 patients were exposed for at least 12 months. In the controlled study, baseline disease characteristics were largely similar in the SPINRAZA-treated patients and sham-control patients except that SPINRAZA-treated patients at baseline had a higher percentage compared to sham-control patients of paradoxical breathing (89% vs 66%), pneumonia or respiratory symptoms (35% vs 22%), swallowing or feeding difficulties (51% vs 29%) and requirement for respiratory support (26% vs 15%). In the controlled study, the most common adverse reactions that occurred in at least 20% of SPINRAZA-treated patients and occurred at least 5% more frequently than in control patients were lower respiratory infection, upper respiratory infection, and constipation. Serious adverse reactions of atelectasis were more frequent in SPINRAZA-treated patients (14%) than in control patients (5%). Because patients in the controlled study were infants, adverse reactions that are verbally reported could not be assessed in this study. Table 1. Adverse Reactions that Occurred in at Least 5% of SPINRAZA Patients and Occurred at Least 5% More Frequently or At Least 2 Times as Frequently Than in Control Patients in the Controlled Study in Infants with Symptomatic SMA 1 Four loading doses followed by 12 mg (5 mL) once every 4 months 2 Includes pneumonia, bronchiolitis, pneumonia viral, respiratory syncytial virus bronchiolitis, lower respiratory tract infection, pneumonia bacterial, bronchitis, bronchitis viral, pneumonia moraxella, pneumonia parainfluenzae viral, lower respiratory tract infection viral, lung infection, pneumonia influenza, pneumonia pseudomonal, pneumonia respiratory syncytial viral 3Includes upper respiratory tract infection, nasopharyngitis, rhinitis, pharyngitis, or tracheitis Adverse Reactions SPINRAZA 12 mg 1 N=80 % Sham-Procedure Control N=41 % Lower respiratory infection2 43 29 Upper respiratory infection3 39 34 Constipation 30 22 Teething 14 7 Upper respiratory tract congestion 6 2 Aspiration 5 2 Ear infection 5 2 Scoliosis 5 2 In an open-label clinical study in infants with symptomatic SMA, severe hyponatremia was reported in a patient treated with SPINRAZA requiring salt supplementation for 14 months. Cases of rash were reported in patients treated with SPINRAZA. One patient, 8 months after starting SPINRAZA treatment, developed painless red macular lesions on the forearm, leg, and foot over an 8-week period. The lesions ulcerated and scabbed over within 4 weeks, and resolved over several months. A second patient developed red macular skin lesions on the cheek and hand ten months after the start of SPINRAZA treatment, which resolved over 3 months. Both cases continued to receive SPINRAZA and had spontaneous resolution of the rash. SPINRAZA may cause a reduction in growth as measured by height when administered to infants, as suggested by observations from the controlled study. It is unknown whether any effect of SPINRAZA on growth would be reversible with cessation of treatment. The most common adverse events in the open-label studies in later onset patients were headache (50%), back pain (41%) and post lumbar puncture syndrome (41%). Most of these events occurred within 5 days of lumbar puncture. Other adverse events in these patients were consistent with adverse reactions observed in the controlled study. 6.2 Immunogenicity The immunogenic response to nusinersen was determined in 126 patients with baseline and post-baseline plasma samples evaluated for anti-drug antibodies (ADAs). Five (4%) patients developed treatment-emergent ADAs, of which 3 were transient and 2 were considered to be persistent. There are insufficient data to evaluate an effect of ADAs on clinical response, adverse events, or the pharmacokinetic profile of nusinersen. The detection of antibody formation is highly dependent on the sensitivity and specificity of the assay. In addition, the observed incidence of antibody (including neutralizing antibody) positivity in an assay may be influenced by several factors including assay methodology, sample handling, timing of sample collection, concomitant medications and underlying disease. For these reasons, comparison of the incidence of antibodies to SPINRAZA in the studies described below with the incidence of antibodies in other studies or to other products may be misleading. 6.3 Postmarketing Experience The following adverse reactions have been identified during post-approval use of SPINRAZA. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. Serious infections (including meningitis) and hydrocephalus have occurred in patients treated with SPINRAZA via lumbar puncture.