* Genmab, J&J collaborate on blood cancer drug Darzalex
* Darzalex recently topped $1 billion in 2017 sales
* J&J has record of European biotech M&A after Actelion buy
LONDON, Nov 30 (Reuters) - Genmab was Europe's second biggest biotech company, until its partner Johnson & Johnson bought Switzerland's Actelion for $30 billion this year and propelled the Danish antibody specialist to the top spot.
Now some investors wonder if the same fate might await Genmab, worth $12 billion, given the soaraway success of its blood cancer drug Darzalex.
J&J sells the drug and pays Genmab a royalty of 12 to 20 percent. With 2017 Darzalex sales already over $1 billion and analysts on average expecting them to reach more than $8 billion annually, those royalties are adding up to serious money.
Bernstein analyst Wimal Kapadia is among those who think J&J might just decide to buy Genmab and avoid royalties altogether, while bringing onboard a smart team of scientists.
For now, however, both J&J and Genmab are lauding the success of their existing relationship.
"It's one of the most successful collaborations we have. We love the partnership," J&J's Chief Scientific Officer Paul Stoffels told Reuters.
He declined to comment on the U.S. healthcare giant's possible interest in buying Genmab in future but said the Danish group had the capital needed to go forward on its own, adding: "They don't need us to be successful."
Indeed, Genmab's strategy is to plough the growing royalty stream from Darzalex into its next wave of medicines. Darzalex is now established as a key treatment in multiple myeloma, where it is moving into earlier stages of the disease.
It is also showing promise in other areas, with clinical trial success in fighting amyloidosis, a rare disease caused by the build-up of an abnormal protein, triggering a $20 million milestone payment from J&J to Genmab on Wednesday.
Genmab Chief Executive Jan van de Winkel says the decision on any eventual sale of the company will be up to shareholders, but he is confident the fast-growing biotech business has a bright future as an independent operation.
"Our focus is to build an independent antibody innovation powerhouse and we think we can create more value for our stakeholders by staying independent than being a part of a larger entity," he said in an interview in London.
Van de Winkel also sees important differences between Genmab and Actelion, with the decision by J&J to snap up the Swiss group driven in large part by a need to plug a revenue hole left by declining sales of J&J's ageing biotech drug Remicade.
"They needed to replace that income and that is exactly what the Actelion products will do. That is a completely different reason, I think, from potentially looking at a company like ours," he said.
"It is up to J&J ... but I hope that we can continue like this for many, many more years." (Reporting by Ben Hirschler; Editing by Adrian Croft)