Genmab A/S announced an amendment to the worldwide agreement to co-develop and commercialize Arzerra (ofatumumab) with GlaxoSmithKline (GSK).

Under the terms of the amendment, Genmab will receive a one-time payment of $4.5 million from GSK upon the FDA's acceptance for review of the filing of the first Biologics License Application (BLA) for ofatumumab in an oncology indication in the USA in exchange for terminating its option to co-promote ofatumumab.

Under the original terms of the companies' agreement, Genmab had an option to co-promote ofatumumab in a targeted oncology setting in the US and in the Nordic region. In addition, if Genmab exercised the co-promotion option, Genmab would have had the option to co-promote GSK's Bexxar and Arranon in the US and Atriance in the relevant countries of the Nordic region. Pursuant to the current amendment, Genmab has sold its co-promotion option rights to GSK. The sale of the co-promotion option does not affect the royalty or milestone revenue that Genmab may receive.

"Under the amendment to our agreement, GSK will now be fully responsible for the entire sales organization for ofatumumab. We believe this is the most cost effective and efficient manner to achieve market penetration and bring value to Genmab if ofatumumab receives approval from the FDA," said Lisa N Drakeman, chief executive officer.

Ofatumumab is an investigational monoclonal antibody that targets a distinct membrane-proximal (close to the cell surface), small loop epitope (a portion of a molecule to which an antibody binds) on the CD20 molecule on B cells. This epitope is different from the binding sites targeted by other CD20 antibodies currently available or in development. The CD20 molecule is a key therapeutic target for B cell malignancies like CLL and NHL because it is expressed on most B cells.