Tesaro Inc. continued its stellar trajectory, filing an S-1 registration statement with the SEC seeking to raise up to $86.3 million in an initial public offering (IPO) to advance rolapitant, its selective neurokinin-1 (NK1) receptor antagonist with an extended plasma half-life.

The lead compound has completed Phase II studies in chemotherapy-induced nausea and vomiting (CINV), postoperative nausea and vomiting and chronic cough.

And that's not all. The filing indicated that Tesaro issued 26.9 million shares of Series B preferred stock on March 21, for net proceeds of about $58.3 million. The shares will be converted into common stock immediately prior to the IPO's closing.

Tesaro became the second biotech in as many days to seek an exit through the IPO gate, following almost to the penny the $86 million registration by Durata Therapeutics Inc., of Morristown, N.J. (See BioWorld Today, March 26, 2012.)

The similarities end there. While Durata is developing compounds targeting skin infections, Waltham, Mass.-based Tesaro is focused on products for oncology patients.

Launched in 2010 with a $20 million Series A financing, Tesaro has moved with lightning speed. The company was co-founded by former executives of MGI Pharma Inc., a Minneapolis-based firm that marketed several cancer drugs, including Dacogen (decitabine) for myelodysplastic syndromes, and was purchased in 2008 by Eisai Co. Ltd. for $3.9 billion. (See BioWorld Today, Dec. 11, 2007, and May 27, 2010.)

In December 2010, Tesaro in-licensed rolapitant from OPKO Health Inc., of Miami, for $121 million, including milestones, double-digit tiered royalties and a 10 percent equity position in Tesaro. Already through Phase II studies, rolapitant had been a Schering-Plough Corp. property, but OPKO bought it for $2 million up front following Schering's 2009 merger with Merck & Co. Inc. (See BioWorld Today, Dec. 16, 2010.)

In cancer patients treated with chemotherapy, the compound showed promising five-day activity in CINV prevention following the administration of a single dose. In addition to meaningful impact on nausea, the drug's characteristics include more rapid onset, longer duration of treatment and lower potential for drug-drug interactions than Emend (aprepitant, Merck & Co.), the only NK-1 receptor antagonist on the market, according to Tesaro. Safety and tolerability of single and repeat doses of the compound have been assessed in more than 1,000 healthy volunteers and cancer patients.

On an annual basis, nearly 7 million CINV treatments are administered on the first day of chemotherapy in the U.S. alone, according to Tesaro, which estimated that 70 percent to 80 percent of cancer patients treated with current standard of care for CINV would benefit from treatment with an NK-1 receptor antagonist. Emend generated $419 million in global revenues last year.

In its S-1 filing, Tesaro said it initiated a global Phase III program for rolapitant and expects to report top-line data from the trial in the second half of 2013. The company plans to present data from a 454-patient Phase II trial evaluating rolapitant in patients at high risk of CINV at the American Society of Clinical Oncology conference in June.

In March 2011, Tesaro acquired exclusive worldwide rights to develop, manufacture, commercialize and distribute small-molecule inhibitors of anaplastic lymphoma kinase (ALK) from Amgen Inc., of Thousand Oaks, Calif., for an undisclosed up-front payment and potential milestone payments and royalties.

Although the ALK program remains in the preclinical stage, Tesaro said in its S-1 that it would pursue an accelerated development pathway for the lead compound in the program, TSR-011 , in non-small-cell lung cancer and other tumor types associated with ALK mutations. The company said it plans to file an investigational new drug application for TSR-011 during the second half of the year.

Tesaro indicated in its filing that it plans to continue in-licensing or acquiring additional product candidates in various stages of development. The company is focusing on compounds that are differentiated from existing therapeutics and supportive care products in oncology and have "well defined, and potentially expeditious, clinical and regulatory pathways."

Unlike most small biotechs, especially those in the oncology space, Tesaro also intends to grow internally rather than partnering to commercialize its pipeline. Leveraging the experience of its senior management, the company said in its filing that "we currently plan to commercialize our portfolio of cancer therapeutics and oncology supportive care products by deploying fully integrated sales and marketing and medical affairs organizations in core strategic markets."

Tesaro's IPO follows a year that saw it crowned as a star of the biotech venture world. The company's $101 million Series B in June 2011 was one of the year's largest pure venture deals in the industry. (See BioWorld Today, June 22, 2011, and Jan. 18, 2012.)

Series B participants included founding investor New Enterprise Associates – which took the largest position in the round – and new investors InterWest Partners, Kleiner Perkins Caufield & Byers (KPCB), Venrock, Pappas Ventures, T. Rowe Price, Oracle Partners, Deerfield Management and Leerink Swann.

At the time, Mary Lynne Hedley, the company's chief scientific officer and co-founder, told BioWorld Today that the company had about a dozen employees and expected to double its head count by the end of last year.

In its S-1, Tesaro reported $39.8 million in cash and equivalents on Dec. 31, 2011, with expenses of $15.4 million for last year.

Tesaro said it plans to list on Nasdaq under the symbol "TSRO." Citigroup, Morgan Stanley and Leerink Swann are joint bookrunners on the deal.

In other financings news:

• Corcept Therapeutics Inc., of Menlo Park, Calif., said investors exercised warrants to purchase approximately 4.2 million shares of common stock purchased in a private placement that closed on April 21 , 2010. The exercise price was $2.96 per share, generating gross proceeds of approximately $12.4 million. Corcept entered a definitive agreement to raise an additional $500,000 through a private placement to the same investors of warrants to purchase approximately 4.2 million shares of common stock at 12.5 cents per share. The new warrants have a three-year term and an exercise price of $4.05 per share, the closing price of Corcept's shares on March 23. Funding of the warrant exercise and offering of new warrants will occur March 29. The company said it would use net proceeds to commercialize Korlym (mifepristone) 300-mg tablets, continue a Phase III trial of mifepristone in the psychotic features of psychotic depression, develop its next-generation compounds and for other corporate purposes. Last month, the FDA approved Korlym for hyperglycemia in patients with Cushing's syndrome. (See BioWorld Today, Feb. 21, 2012.)

• Merrimack Pharmaceuticals Inc., of Cambridge, Mass., amended the S-1 for its initial public offering, filed in July 2011. The company will seek to raise $100 million, down from $172.5 million, by offering 14.3 million shares at an approximate price of $7 each. The company said it would grant underwriters an option to purchase up to 2.1 million additional shares to cover overallotments, potentially generating an additional $15 million. Merrimack's lead candidate, MM-398, is a stable nanotherapeutic encapsulation of irinotecan preparing to enter a pivotal Phase III trial in pancreatic cancer. The company said it would allocate up to $40 million for the clinical development program for MM-398; up to $22 million to develop MM-111, a bispecific antibody targeting HER2; up to $18 million for MM-302, a nanotherapeutic encapsulation of doxorubicin attached to antibodies targeting the ErbB2/HER2 receptor; up to $15 million for MM-151, an oligoclonal therapeutic consisting of three fully human antibodies designed to bind epitopes of EGFR; and the additional capital for R&D, including the initiation of human trials for earlier-stage candidates. Merrimack plans to list on Nasdaq under the symbol "MACK." J.P. Morgan is bookrunner on the deal. (See BioWorld Today, July 12, 2011.)

• OncoSec Medical Inc., of San Diego, said it would seek to raise $7.75 million through a registered public offering of 31 million shares of common stock at 25 cents per share and warrants to purchase an additional 31 million shares at 35 cents per share for a term of five years. The price represented a 24 percent discount over the stock's previous closing price of 33 cents on March 24. Shares (OTCQB:ONCS) dropped 30.6 percent Monday, closing at 23 cents, after the offering was disclosed. Rodman & Renshaw LLC acted as the exclusive placement agent for the transaction, which is expected to close March 28.

• Sirona Biochem Corp., of Vancouver, British Columbia, closed a private placement of 14.1 million units at C10 cents (US10 cents) each for proceeds of C$1.4 million. Each unit consists of one common share and one warrant to purchase an additional common share at 18 cents for a term of two years. The securities are subject to a four-month holding period.