Biogen Idec
Projected 2018 sales:
$2.085 billion
2012 sales: $2.913 billion

In an MS arena growing ever more competitive, Biogen Idec ($BIIB) has adopted its own strategy: corner the market. The company boasts the much-anticipated Tecfidera, an oral MS drug that competes with Novartis' ($NVS) Gilenya and Sanofi's ($SNY) Aubagio, but which some say could be even safer and more effective than those treatments. But it was Avonex that first brought Biogen into the MS conversation.

Though Avonex, a once-weekly injectable treatment, was groundbreaking when it first gained FDA approval in 1996, it now needs help preserving its market share as oral alternatives pop up around the industry. To keep Avonex competitive, Biogen has been tweaking its drug-delivery options. These alterations are subtle yet significant ways to make the drug more attractive to patients; for instance, last year the FDA signed off on Biogen's Avonex Pen, billed by the company as the first "intramuscular autoinjector" approved for MS and one it hoped would reduce "injection anxiety" and "pain".

The company is also working on a longer-lasting version of Avonex, which in January of this year showed reduced relapse rates in MS patients.

For more:
Biogen prices Tecfidera below oral MS rival Gilenya
Biogen Idec, Sanofi secure European nods for blockbuster MS hopefuls
Biogen Idec secures FDA nod for Avonex delivery accessory