As a case study of patent coverage for a repurposed drug, Biogen Idec's approach 
for Tecfidera(®), an oral formulation of dimethyl fumarate, was analyzed. While 
mixtures of fumarates have been used for over 50 years to treat psoriasis, 
Tecifidera is approved for the treatment of relapsing-remitting multiple 
sclerosis. Biogen pursued claims to pharmaceutical formulations and useful doses 
for treating multiple sclerosis, an approach that is relevant to pharmaceutical 
lifecycle management in general. A survey of recent US, EP, and PCT patent 
applications indicate other companies are developing competing fumarate 
formulations. While it is possible to pursue secondary patents for compounds 
without composition of matter coverage, regulatory data exclusivity provides 
additional protection to delay competitors.