Autoinjectable Subcutaneous Ofatumumab Depleted B Cells and had Bioequivalence With Prefilled Syringe Delivery 

Ofatumumab 20 mg delivered subcutanously with a monthly dosing regimen resulted in rapid, close to complete and sustained B-cell depletion over 12 weeks across patient groups and delivery with an autoinjector or a prefilled syringe were bioequivalent. The autoinjector allows for monthly at-home self-administration and can help reduce treatment burden.

A loading dose of ofatumumab delivered with the autoinjector rapidly depleted B cells (from baseline 210-220 cells/mcL to 2-4 cells/mcL) by day 14. B-cell depletion was sustained at ≤1 cell/mcL at 12 weeks with monthly dosing. Most participants (77%-87%) achieved B-cell counts of <10 cells/mcL by Day 14 and almost all (92%-95%) achieved B-cell counts of <10 cells/mcL by week 4. B-cell counts <10 cells/mcL were maintained in 97% to 100% of participants through week 12. 

The geometric mean ratios for ofatumumab delivered via the autoinjector vs the prefilled syringe for AUCtau and Cmax were 1.03 and 1.00, respectively. The safety profile was similar for all groups and in line with previous clinical trial that showed ofatumumab had superior efficacy vs oral teriflunomide 14 mg once daily for relapsing multiple sclerosis (RMS).

In this 12-week open-label phase 2 bioequivalence study, participants received ofatumumab 20 mg (0.4 mL) subcutaneous injections every 4 weeks from week 4 onwards after receiving initial loading doses on days 1, 7, and 14. Participants were randomly assigned to receive ofatumumab with different devices and inject different sites (abdomen or thigh). B-cell depletion was measured 9 times and bioequivalence was determined by measuring area under curve from the start to the end of 4-week dosing intervals (AUCtau) and maximum plasma concentration (Cmax) at week 8.