Ofatumumab


Ofatumumab is a fully human monoclonal antibody to CD20, which appears to inhibit early-stage B lymphocyte activation. It is FDA approved for treating chronic lymphocytic leukemia that is refractory to fludarabine and alemtuzumab and has also shown potential in treating follicular lymphoma, diffuse large B cell lymphoma, rheumatoid arthritis and relapsing remitting multiple sclerosis. Ofatumumab has also received conditional approval in Europe for the treatment of refractory chronic lymphocytic leukemia. This makes ofatumumab the first marketing application for an antibody produced by Genmab, as well as the first human monoclonal antibody which targets the CD20 molecule that will be available for patients with refractory CLL.

Medical uses

Its only indication that has received regulatory approval is chronic lymphocytic leukemia.

Adverse effects

Adverse effects by frequency:
Very common :
Common :'
Uncommon :
Rare :
Ofatumumab has received a black box warning regarding the potential for it to cause progressive multifocal leukoencephalopathy and hepatitis B reactivation. Likewise it is also advised that doctors watch cautiously for small bowel obstruction, neutropenia, thrombocytopenia, infusion reactions or an increased risk for infection.

Contraindications

It is contraindicated in individuals that have hypersensitivity to ofatumumab or any of its excipients.

Interactions

No formal drug interaction studies have been conducted with ofatumumab. Although it is advised that patients are not administered live virus vaccines while undergoing treatment with ofatumumab due to the compromised ability to fight the attenuated viruses seen in patients being treated with ofatumumab.

Mechanism

Ofatumumab is a humanised anti-CD20 monoclonal antibody whose epitope is distinct from that of rituximab. The CD20 antigen is expressed on solely B cell lymphocytes. Compared with rituximab, ofatumumab binds more tightly to CD20 with a slower off-rate. It causes cytotoxicity in the cells that express CD20 by means of complement-dependent cytotoxicity and antibody-dependent cellular cytotoxicity.

History

It received EMA approval in June 2010 and Health Canada approval on the 13th of August 2012. and it first received FDA approval on April 17, 2014, for use in combination with chlorambucil, for the treatment of previously untreated patients with CLL for whom fludarabine-based therapy is considered inappropriate MHRA approval on the 19th of April 2010,