One factor I neglected mentioning is BG-12 launch, which could be more impressive than what we've seen with Gilenya, and in this case a 20% switch is too optimistic.
Assuming thrice-weekly Copaxone entry in early 2014…
That may be optimistic. Before reviewing the NDA, the FDA may want to see the results of GALA’s open-label safety extension, which is slated to run until May 2014 (http://clinicaltrials.gov/ct2/show/NCT01067521 ). If so, market entry will likely be delayed until mid 2015.