Gammaplex 10% is a new, ready-prepared IVIG. A recent clinical trial established the bioequivalence of the Gammaplex 10% and 5% formulations. Here we compare the infusion durations and related tolerability of the two formulations administered using 15-minute titration periods. GMX07 (NCT01963143) was a phase 3, multicenter, open-label, randomized, 2-period, crossover bioequivalence trial that evaluated the pharmacokinetics, safety, and tolerability of Gammaplex 10% in adult and pediatric patients with primary immunodeficiency diseases. Bioequivalence of Gammaplex 10% and Gammaplex 5% was assessed in adults. For each infusion, the infusion rate was increased at 15-minute intervals depending on subjects' tolerability. The median infusion duration for Gammaplex 10% (n=32) was 108.5 min (range 66-252), compared with 161 min (range 75-348) for Gammaplex 5% (n=33). Of subjects receiving Gammaplex 10% and 5% infusions, 96% and 94%, respectively, reached and were maintained at the highest infusion rate. Of 166 Gammaplex 10% infusions, 27 (16.3%) were temporally associated with ≥1 product-related adverse event (AE) versus 32 of 163 (19.6%) Gammaplex 5% infusions. The most common (≥5% in either group) product-related AEs reported during or within 1 hour of infusions' end were headache (9.4% [Gammaplex 10%] vs 15.2% [Gammaplex 5%]), migraine (0% vs 6.1%), pyrexia (6.3% vs 0%), and fatigue (3.1% vs 6.1%). Gammaplex 10%, the first 10% IVIG with a 15-minute titration schedule, allows shorter infusion durations than a 5% IVIG product, with a similar tolerability profile.