Portola Pharmaceuticals Inc. has become the latest biotech to go public in a rush driven by surging financial markets. The South San Francisco-based company has become the 12th biotech in the 2013 IPO class, and another dozen are filed and pending, signaling a definitive end to the long wait for markets to regain avid interest in new biotech opportunities following the market crash of 2008.

Portola priced 8,422,758 shares of common stock at $14.50 per share, with a 30-day option for underwriters to purchase an additional 1,263,413 shares to cover overallotments. The funds will support Portola's pipeline of drugs for thrombosis, hematologic disorders and inflammation.

The price fell squarely within the company's planned range of $13 to $16 per share. Its stock will trade on Nasdaq under the symbol PTLA. The stock closed at $15.15 Wednesday, up 65 cents over its opening price.

Its once-daily Factor Xa inhibitor, betrixaban, is in Phase III studies for venous thromboembolism in acutely ill patients. That population has no currently approved anticoagulant for VTE prophylaxis.

It is also developing PRT4445, a Factor Xa inhibitor antidote and companion to betrixaban, in a Phase II proof-of-concept study. The product is designed to reverse anticoagulant activity in patients treated with Factor Xa inhibitor who have an uncontrolled bleeding episode or emergency surgery.

Portola has partnered with Bristol-Myers Squibb Co. and Pfizer Inc. to develop PRT4445 with Eliquis (apixaban), and with Bayer AG and Janssen Pharmaceuticals Inc. for PRT4445 with Xarelto (rivaroxaban). Both programs are in Phase II trials, while Portola retains full, commercial right to PRT4445.

It also has an orally available dual Syk-JAK inhibitor, PRT2070, which it is seeking to move into Phase II studies in patients with B-cell hematologic cancers who have failed or relapsed on existing therapies or development candidates, including those with identified mutations.

Another product candidate, PRT2607, is partnered with Biogen Idec Inc. in autoimmune and inflammatory disorders, including rheumatoid arthritis and systemic lupus erythematosus. (See BioWorld Today, Oct. 28, 2011.)

Portola is classified as an emerging growth company under the Jumpstart Our Business Startups Act of 2012.

IPOs have caught fire in recent weeks, with four biotechs opened to trading in the month of May alone. GW Pharma plc (NASDAQ:GWPH) commenced trading on May 1, pricing at $8.90, and closed at $8.88 Wednesday. Insys Therapeutics Inc. (NASDAQ:INSY) debuted at $8 per share, and has surged as high as $11.39 since then, with its last close at $10.18.

Receptos Inc. (NASDAQ:RCPT) began trading at $14 per share on May 9, and has trading consistently above that price since, closing at $14.29 Wednesday. And Lyon, France-based Erytech Pharma SA commenced trading in Paris at €11.60 per share, raising €16.7 million (US$21.4 million) for the company. Erytech stock (ERYP:EN) last closed at €10.80.

In other financings news:

• Aeterna Zentaris Inc., of Quebec City, entered an at-the-market sales agreement with MLV and Co. LLC. to sell up to 2.5 million common shares on the Nasdaq market up to an aggregate amount of $4.6 million. MLV will be the sales agent for those transactions, and shares will be sold at prevailing market prices.

• Cyclacel Pharmaceuticals Inc., of Berkeley Heights, N.J., closed an underwritten public offering of 6,833,334 shares of common stock at $3 per share for gross proceeds of $20.5 million. Net proceeds will be about $19 million, and will be used to support its pivotal Phase III (SEAMLESS) trial of sapacitabine.

• Ironwood Pharmaceuticals Inc., of Cambridge, Mass., priced a public offering of 10.5 million shares of Class A common stock at $13 per share for gross proceeds of $136.5 million. Net proceeds will support the launch of Linzess (linaclotide) in the U.S., and fund development to strengthen the clinical profile of Linzess and expand the product label.

• NPS Pharmaceuticals Inc., of Bedminster, N.J., priced a public offering of 6 million shares of stock at $14.53 per share for gross proceeds of $87.2 million, to close on or about May 24. Underwriters are granted a 30-day option to purchase an additional 900,000 shares to cover over-allotments.

• Oligomerix Inc., of New York, completed a $2.8M Series B financing, which included both the issuance of new convertible preferred shares and warrants. The funds will be applied to advance their Alzheimer's disease drug discovery programs targeting tau protein oligomers that have recently been shown to be neurotoxic, impair memory formation and cause disease progression in disease models.

• Stemline Therapeutics Inc., of New York, closed a public offering of 4,137,931 shares of common stock at $14.50 per share. Gross proceeds are $60 million, before underwriting discounts and commissions and other expenses.

• TheraCoat Ltd., of Raanana, Israel, raised $7 million from private investors and venture funds in Israel and other countries. Investors included Pontifax and CHealth Fund. In conjunction with the financing, Chaim Hurvitz, of CHealth and Ran Nussbaum, of Pontifax, joined TheraCoat's board. The company's platform technology is designed to improve drug delivery into internal body cavities.