Rare disease drug development has ballooned in just three years, powered by the success of independent biotechs like Alexion, Big Pharma’s entrée into the field, and pressure from regulators and payors that is dis-incentivizing development of traditional primary care drugs. The positive momentum has intensified dealmaking in the orphan drug space and is giving investors confidence to back rare disease-focused start-ups. Some have coined the resulting movement the “orphan drug bubble,” but interest isn’t likely to deflate soon – at least not as long as Big Pharma continues to invest in the area and industry is able to sustain a favorable reimbursement climate for ultra-premium-priced drugs.

The Dealmaking column is a survey of recent transactions, including strategic alliances, mergers & acquisitions, and financings, in the life sciences industries. Deals are listed by the following industry sectors: in vitro diagnostics, pharmaceuticals, medical devices, and research/analytical instrumentation and reagents. All transactions are excerpted from Elsevier's Strategic Transactions database, providing comprehensive transaction coverage from 1991 to the present.

The biotech, which is enjoying growing sales of high-priced, ultra-orphan terminal complement inhibitor Soliris, also has a pipeline of four other clinical and preclinical candidates for rare diseases.

Alexion could pay as much as $1.08 billion for access to Enobia's mid-stage rare disease compound asfotase alpha.