VentureBeat

ImaRx, a Tuscon, Ariz., biotech developing new ways to dissolve blood clots in the lungs, lowered its IPO sights and now expects to raise no more than $17.3 million in the offering. (Its latest SEC filing is here.) Late last month, the company had hoped to raise as much as $25.9 million by pricing its shares between $6.50 and $7.50 apiece.

ImaRx now expects to price its shares at $5 apiece. That will value the company at $50 million following the offering. This is the company’s second shot at an initial offering, and it represents a long decline in ImaRx’s IPO hopes. The company previously hoped to raise $75 million with an IPO in May 2006, a number that had fallen to $60 million by the time it withdrew its application last December. The company re-filed this May.

ImaRx is working on a combination ultrasound and “microbubble” technique for dissolving dangerous blood clots that can lead to stroke. Its microbubbles are composed of an outer fatty-molecule shell and an inert gas, and are small enough to theoretically penetrate blood clots. The microbubbles expand and contract when ultrasound is applied, presumably generating enough dynamic motion to break up a clot. That technique, used in combination with a blood-thinning drug called tissue plasminogen activator, or tPA, is currently in early-stage human tests.

New strategies for attacking clots that can cause stroke or heart attacks are very much in vogue these days. Among venture-backed firms in the field that have recently received funding are EndoVention, Ekos and Portola Pharmaceuticals.

Portola Pharmaceuticals, a South San Francisco, Calif., biotech aiming to develop treatments for blood clots and other heart-related problems, raised $70 million in a third round of financing dominated by late-stage and public-market investors.

Among new investors in the round were Brookside Capital; AllianceBernstein; Teachers’ Private Capital, the private investment arm of Ontario Teachers’ Pension Plan; Goldman Sachs, T. Rowe Price, IBTM and CIDC. They were joined by existing investors Abingworth, Alta Partners, Advanced Technology Ventures, Frazier
Healthcare Ventures, MPM Capital, Prospect Ventures and Sutter Hill Ventures.

Portola plans to use the funding for additional clinical trials of its two leading drug candidates, both experimental blood thinners targeting different blood proteins that promote coagulation. PRT054021, an oral molecule that inhibits Factor Xa, showed promising signs in a recent mid-stage human test, and will advance into further clinical trials. Meanwhile, PRT060128, which prevents blood platelets from aggregating, has completed early trials and should move into mid-stage testing by the second half of 2007. Should they receive regulatory approval, both compounds would compete with blood thinners already on the market.

Portola aims to go public and may do so as early as next year, the company’s chief financial officer, Mardi Dier, told VentureWire (subscription required).