Already owner of about 60% of the troubled antibiotic firm, Innoviva agrees to pay $2.20 per share for all outstanding stock in Entasis. Roche, KaliVir partner on oncolytic virus therapies.

Another blow-out quarter from Pfizer provided the impetus for an acquisition. But the history of recent commercial-stage biotech transactions and the risky nature of all early-stage companies suggest that the floodgates will not burst open.

Draft legislation would undo the Catalyst decision prohibiting FDA from providing separate orphan exclusivity periods for different subpopulations and alter the Genus ruling by requiring FDA to treat contrast agents, radioactive drugs and OTC monograph drugs as drugs.

Federal court decision said the FDA cannot grant orphan exclusivity for subpopulations of a disease, which agency officials fear could damage pediatric rare disease drug development.