Four public biotechs raised over $300 million in equity last week, including big deals by Infinity Pharmaceuticals Inc. and Sarepta Therapeutics Inc. As a result, biotech companies have already pulled in over $1.7 billion in follow-ons this quarter, more than twice what was raised in 4Q11.

The biggest week of the quarter came in late October, when companies raised $773.1 million in follow-ons. But this included $511.6 million that went to Shanghai Fosun Pharmaceutical Group Co. Ltd., which has manufacturing, healthcare services and distribution businesses, as well as R&D.