Five funds raised more than $1bn to back biotech firms; Arcus leads recent VC rounds with $107m GV-backed Series C; Celgene, Valeant sell notes to retire debt; and Alnylam cashes in on investor goodwill.

The speed with which TG Therapeutics burst on the scene, along with the impressive potency and safety of its novel combinations of cancer drugs, has perhaps blinded observers to the unique business model that has carried it this far.

Two and a half years after Calistoga Pharmaceuticals was acquired by Gilead Sciences for up to $600m, Frazier Healthcare finally lured Calistoga's former CEO Carol Gallagher to help the venture capital firm replicate its successful investment in the cancer drug developer.

Rather than continue down the path to a public offering, Aragon sells to J&J for a hefty price. Also, MedImmune strikes a diabetes and obesity deal with NGM, Teva buys respiratory drug maker MicroDose, and Sanofi allies with the Curie Institute to study ovarian cancer.