SPL Set ID: 81356b45-1cb7-4eef-88ea-e44cc18b47c5

Tofersen, an antisense oligonucleotide, is a 20-base residue (20-mer) 5-10-5 MOE gapmer mixed backbone oligonucleotide. Of the nineteen internucleotide linkages, fifteen are 3′-O to 5′-O phosphorothioate diesters, and four are 3′-O to 5′-O phosphate diesters. Ten of the twenty sugar residues are 2-deoxy-D-ribose and the remainder are 2′-O-(2-methoxyethyl)-D-ribose (MOE). The residues are arranged so that there are five MOE nucleosides at the 5′ and 3′-ends of the molecule flanking a gap of ten 2′-deoxynucleosides. The cytosine and uridine bases are methylated at the 5-position. The structural formula is: Figure 1: Structural Formula for Tofersen The molecular formula is C 230 H 317 N 72 O 123 P 19 S 15 and the molecular weight is 7127.86 atomic mass units (amu). QALSODY is supplied as a sterile, preservative-free, clear, and colorless to slightly yellow solution in a Type I glass vial to be administered by intrathecal administration. Each vial of drug product contains a single dose of 100 mg tofersen at a concentration of 6.7 mg/mL in a formulation containing 0.21 mg/mL calcium chloride dihydrate, 0.11 mg/mL dibasic sodium phosphate, 0.16 mg/mL magnesium chloride hexahydrate, 0.03 mg/mL monobasic sodium phosphate, 0.22 mg/mL potassium chloride, 8.77 mg/mL sodium chloride, and water for injection. The pH of QALSODY is approximately 7.2 (range 6.7 to 7.7). Figure 1