Genmab of Denmark has ended its search for a partner for its most promising compound and landed a deal with GlaxoSmithKline that could be worth over £1 billion.

The agreement covers HuMax-CD20 (ofatumumab), a fully human monoclonal antibody which is in late stage development for CD20 positive B-cell chronic lymphocytic leukemia and follicular non-Hodgkin's lymphoma and in Phase II for rheumatoid arthritis.

Under the terms of the alliance, Genmab will receive a license fee of £52 million and GSK will also invest £183 million to purchase almost 4.5 million shares. In total, and "in the event of full commercial success, in cancer and various autoimmune and inflammatory diseases," the pact could be worth £ 1.1 billion and in addition, Genmab will be entitled to receive tiered double-digit royalties on sales of HuMax-CD20.

As well as getting global rights to HuMax-CD20, the tie-up also gives GSK options to CD20 Unibody, Genmab’s next-generation antibody technology.

This is exactly the type of deal that chief executive Lisa Drakeman told PharmaTimes World News that the firm was looking for in an interview earlier this month and GSK brings more to the table than just cash. The Danish group is not simply licensing out the compound but will be responsible for development costs until 2008 and will have an option to co-promote HuMax-CD20 as a cancer treatment in the USA and the Nordic region. Genmab may also co-promote GSK’s anticancer agents Bexxar (tositumomab and I131) and Arranon (nelarabine) in the USA and the latter drug in Nordic countries where it will be sold as Atriance.

Potential sales of over $2 billion

The huge sums involved in this deal, the biggest ever agreement of this type sealed by a biotechnology company, reveals the potential the two firms see in the HuMax-CD20 programme. Ms Drakeman, who said that she hopes the drug will be filed for regulatory approval by 2008, could generate well over $2 billion in annual sales, though some feel even that is a little conservative.

Analysts at Jyske Bank, who have raised their rating on the stock to buy from accumulate, forecast peak sales of $2.8 billion, and this could rise if regulatory approvals for HuMax-CD20 for its three indications are secured.

As for GSK, this is the second deal it has made in the antibodies field in less than a fortnight, following its decision to buy the UK’s Domantis for £230 million.