What pack sizes are listed for the Xolair (omalizumab) 150 mg pre-filled syringe with a 27-gauge needle and purple plunger?

Xolair (omalizumab) 150 mg pre-filled syringes with a 27-gauge needle and purple plunger are listed in packs of 1 syringe and multipacks of 3 (3 × 1) or 6 (6 × 1) syringes; not all pack sizes may be marketed.