General Information

Kesimpta (ofatumumab) is a CD20-directed cytolytic antibody.

Kesimpta is specifically indicated for the treatment of relapsing forms of multiple sclerosis (MS), to include clinically isolated syndrome, relapsing-remitting disease, and active secondary progressive disease, in adults.

Kesimpta is supplied as an injection for subcutaneous administration. 

Prior to first Kesimpta administration, patients should be screened for hepatitis B and serum immunoglobulins. Because vaccination with live-attenuated or live vaccines is not recommended during treatment and after discontinuation until B-cell repletion, administer all immunizations according to immunization guidelines at least 4 weeks prior to initiation of Kesimpta for live or live-attenuated vaccines, and whenever possible, at least 2 weeks prior to initiation of Kesimpta for inactivated vaccines.

The recommended initial dose of Kesimpta is 20 mg by subcutaneous injection at Weeks 0, 1, and 2, followed by subsequent dosing of 20 mg by subcutaneous injection once monthly starting at Week 4. If an injection of Kesimpta is missed, it should be administered as soon as possible without waiting until the next scheduled dose. Subsequent doses should be administered at the recommended intervals.

Mechanism of Action

Kesimpta (ofatumumab) is a CD20-directed cytolytic antibody. The precise mechanism by which ofatumumab exerts its therapeutic effects in multiple sclerosis is unknown, but is presumed to involve binding to CD20, a cell surface antigen present on pre-B and mature B lymphocytes. Following cell surface binding to B lymphocytes, ofatumumab results in antibody-dependent cellular cytolysis and complement-mediated lysis.

Side Effects

Adverse effects associated with the use of Kesimpta may include, but are not limited to, the following:

• upper respiratory tract infection
• headache
• injection-related reactions
• local injection site reactions

Clinical Trial Results

The FDA approval of Kesimpta was based on the ASCLEPIOS I and II phase 3 studies. The twin, identical design, flexible duration (up to 30 months), double-blind, randomized, multi-center studies evaluated the safety and efficacy of Kesimpta 20 mg monthly subcutaneous injections versus teriflunomide 14 mg oral tablets taken once daily in adults with RMS. The ASCLEPIOS I and II studies enrolled 1,882 patients with MS, between the ages of 18 and 55 years, with an Expanded Disability Status Scale (EDSS) score between 0 and 5.5. The studies were conducted in over 350 sites in 37 countries. Kesimpta demonstrated a significant reduction in annualized relapse rate (ARR) by 51% (0.11 vs 0.22) and 59% (0.10 vs 0.25) compared with teriflunomide in ASCLEPIOS I and II, respectively (primary endpoint). Kesimpta also showed a relative risk reduction of 34.4% in 3-month confirmed disability progression (CDP) compared with teriflunomide in a pre-specified meta-analysis, as defined in ASCLEPIOS. Kesimpta showed significant reduction of both Gd+ T1 lesions and new or enlarging T2 lesions. It significantly reduced the mean number of both Gd+ T1 lesions (98% and 94% relative reduction in ASCLEPIOS I and II, respectively, and new or enlarging T2 lesions (82% and 85% relative reduction in ASCLEPIOS I and II, respectively) vs teriflunomide.