Biogen quickly became the leader in the multiple sclerosis market, growing Avonex into a billion-dollar drug. Now Biogen's dominance is being challenged by Serono and its new partner Pfizer, co-promoting another interferon, Rebif, which came to market with head-to-head data showing it's better. Biogen maintains that Avonex is the best treatment, and is working to support its contention. The biotech is confident that the relationships it has built over time, and strengthened through services, will be hard for newcomers to push aside. The potential for leverage is what attracts Pfizer to this specialist market: it aims to sell Rebif broadly. Its 300 neurology sales reps will carry other products for the co-morbidities MS patients suffer--so the ROI could be good, even if Rebif itself isn't a huge seller. An industry whose pipeline is far richer in niche than GP products will be watching this marketing battle: will Biogen's focus carry the day--or can Pfizer turn a late-entry specialist product into a market leader and in the process, make significant money for itself?

GSK achieved a first-in-class market oncology launch in 2020, but will have to increase that hit rate in order to fulfil its blockbuster ambitions.