Washington Editor

Portola Pharmaceuticals Inc. raised $70 million in Series C funding, easily one of the biotech industry's biggest private financing rounds this year.

The cardiovascular-focused company, of South San Francisco, plans to use the new money to advance the development of its two clinical-stage anti-thrombotics: PRT054021, a Factor Xa inhibitor, and PRT060128, an ADP receptor antagonist.

Both clinical candidates, directed at targets for which already-marketed drugs generate billions of dollars in annual sales, are being developed as improvements to those therapies.

"Investors, current and new, have seen good clinical progress," Portola Chief Financial Officer Mardi Dier told BioWorld Today, "and they also see a tremendous opportunity in this space."

Previous financings brought in $88 million since the company's inception four years ago. The latest funds have boosted Portola's bank account to more than $100 million, which Dier said should last through next year if the company achieves its goal of securing a partner for one of its lead compounds in the next 12 months.

"Ultimately, we plan to partner both programs," she said, adding that such discussions are ongoing, but any eventual deals would be made sequentially. "Finding the right partner with the right terms is a priority."

Based on recently reported data from Phase II testing of PRT054021, which demonstrated the safety and efficacy of two doses of the anticoagulant in preventing venous thromboembolism after orthopedic surgery, Portola plans to advance the compound into Phase III for deep vein thrombosis pending FDA meetings and other consultations to refine study protocols. Dier said the company plans to begin pivotal work at the beginning of next year.

Specific findings from PRT054021's Phase II study are scheduled for presentation in July at the International Society on Thrombosis and Hemostasis meeting in Geneva.

Portola is positioning the once-daily oral drug as a more convenient upgrade to warfarin because of its low peak-to-trough variability. That is, patients on PRT054021 don't need to be monitored as they do when treated with warfarin, which works to varying degrees from one patient to the next. The company also plans on developing it for stroke prevention in patients with atrial fibrillation and for the secondary prevention of myocardial infarction and stroke.

In addition, Portola has completed Phase I studies of both intravenous and oral formulations of PRT060128, a direct-acting anti-platelet therapy, and expects its Phase II program to begin in the second half of this year. It's seen as an improvement over Plavix (clopidogrel bisulfate, Bristol-Myers Squibb Co. and Sanofi Aventis Group) in terms of convenience, because of its quicker onset of action, administration flexibility for acute and chronic use, as well as reversibility. That latter characteristic allows PRT060128 to be dosed within 24 hours of surgery, because of its short half-life, whereas Plavix patients often require several washout days before procedures can be scheduled.

Portola plans on developing it for patients with acute coronary syndrome, for the prevention of cardiovascular events in patients undergoing percutaneous coronary intervention and for the secondary prevention of myocardial infarction and stroke.

Both PRT054021 and PRT060128 have roots in Millennium Pharmaceuticals Inc., of Cambridge, Mass., as does Portola's management team.

Its latest financing includes several new investors: Brookside Capital, of Greenwich, Conn.; AllianceBernstein LP, of New York; Teachers' Private Capital, the private investment arm of Ontario Teachers' Pension Plan; Goldman Sachs, of New York; T. Rowe Price, of New York; IBT Management Corp., of Taiwan; and China Investment & Development Co., of Taiwan.

Those backers were joined by several existing investors: Abingworth, of London; Alta Partners, of San Francisco; Advanced Technology Ventures, of Waltham, Mass.; Frazier Healthcare, of Seattle; MPM Capital, of Boston; Prospect Ventures, of Palo Alto, Calif.; and Sutter Hill Ventures, also of Palo Alto.