With biotech stocks sizzling, drug developers are bringing home the bacon

When biotech stocks and IPOs are booming, drug developers can always tap investors for more cash. And follow-on offerings have become all the rage in biotech circles.

In just the last day four biotechs raised $276 million from follow-on offerings, part of a dam burst of stock sales that's been pumping money into the biotechs. Popular Epizyme ($EPZM) led the way with an $88 million raise. Halozyme Therapeutics ($HALO) raised $100 million, while Agenus ($AGEN) banked $52 million and Idera ($IDRA) raised $36 million.

Epizyme's shares have been on something of a roller coaster ride in recent months, shooting up most recently on news of $29 million in milestones paid by GlaxoSmithKline ($GSK). Epizyme had a very successful IPO last year, raising $80 million and helping set the hot tone to the ongoing biotech IPO boom. This new cash will go, in part, to back the development of EPZ-5676, including the costs of the expansion stage of its ongoing Phase I clinical trial of EPZ-5676 in MLL-r adult patients and MLL-PTD adult patients and its planned Phase Ib clinical trial of EPZ-5676 in MLL-r pediatric patients.

Idera Pharmaceuticals has seen its share price soar 560% this year, after its toll-like receptor program foundered in a mid-stage study for head and neck cancer in 2012. Agenus was on a downward track for most of last year, though it reported positive Phase II brain cancer vaccine data late last year. And Halozyme also took its share of knocks last year after trouble with a ViroPharma program that used its delivery tech. Nevertheless its stock is up 99% over the past year.

For the public biotechs, strong stock prices make it possible for the industry to add billions of dollars in cash to back R&D. Combined with a steady flow of about $4.5 billion a year in venture cash and more than $3.5 billion from IPOs last year, the follow-ons are helping foster company growth, accelerating development programs.

As long as the sun keeps shining on Wall Street, biotechs will keep making hay. 

- here's the release on Epizyme
- here's the release on Halozyme
- here's the release on Idera
- here's the release on Agenus

Special Report: The top 10 biotech IPOs of 2013 - Epizyme