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Ambit 'FLT3's with Initial Public Offering Again in $57.5M Filing


By Marie Powers
Staff Writer

Late Wednesday, Ambit Biosciences Inc. disclosed an S-1 filing with the SEC for an initial public offering (IPO) of its common stock, expected to trade on the Nasdaq market under the symbol "AMBI." The company is seeking to raise up to $57.5 million, though the number of shares and price range were not yet determined.

Ambit said its IPO would be filed as an emerging growth company, as defined in the Jumpstart Our Business Startups Act of 2012.

The company's lead candidate, quizartinib, formerly known as AC220, is a once-daily, oral selective inhibitor of FMS-like tyrosine kinase-3 (FLT3) that completed a Phase II study last year in relapsed/refractory acute myeloid leukemia (AML) and newly diagnosed AML in combination with chemotherapy and maintenance following hematopoietic stem cell transplantation (HSCT). In November 2012, the company raised $50 million from existing investors to begin prepping for the Phase III, expected to begin next year.

San Diego-based Ambit is partnered with Astellas Pharma Inc. to research, develop and commercialize certain FLT3 kinase inhibitors in oncology and non-oncology indications, including quizartinib. That deal, struck in 2009, brought Ambit $40 million up front and $350 million in potential pre-market milestones, including $160 million related to the AML indication. The company likely will see some of that money next year, when the Phase III is launched. (See BioWorld Today, Dec. 21, 2009.)

Ambit retained a U.S. co-promotion option in the deal.

The company's second-generation FLT3 inhibitor was developed by way of its KINOMEscan profiling technology, moving from initial chemistry to clinical candidate selection for investigational new drug-enabling studies in 18 months. With Astellas, Ambit is developing AC220 for AML in patients who have the internal tandem duplication mutation in the FLT3 kinase, as well as other indications.

Behind the compound are other candidates in the class for cancer and more, including autoimmune and inflammatory disorders.

Founded in 2000, Ambit attracted at least $113 million in four rounds and in 2005 inked kinase screening collaborations with a trifecta of big pharmas: GlaxoSmithKline plc, Bristol-Myers Squibb Co. and Pfizer Inc.

In recent years, the company's executive suite has seen some turnover. After nearly a decade as CEO, M. Scott Salka was replaced in July 2010 by Alan Lewis, who had joined Ambit a few months earlier as executive chairman. Lewis, along with Alan Fuhrman as chief financial officer, Christopher Morl as chief operating officer and Faheem Hasnain as chairman, pushed Ambit toward the public markets through an IPO, filed in November 2010, seeking $86.3 million. (See BioWorld Today, Nov. 9, 2010.)

In June 2011, the company withdrew the offering, citing a market that was not "sufficiently attractive" to move forward. Instead, its venture syndicate stepped up for a $30 million Series D-2 round to help support an ongoing Phase II trial of quizartinib in AML. Apposite Capital LLP led that round, with participation from existing investors Perseus-Soros Biopharmaceutical Fund, OrbiMed Advisors, Forward Ventures, Roche Venture Fund, MedImmune Ventures, GIMV, Growth Works, Genechem, Radius Ventures, NovaQuest and Horizon Technology Finance. (See BioWorld Today, June 13, 2011.)

In November 2011, Michael Martino was named Ambit's CEO, joining the company from CareFusion Corp., where he had served as senior vice president and general manager of diagnostics and senior vice president of innovation, business development and strategy. About the same time, the company reported updated results from an interim analysis of the Phase II of quizartinib at the American Society of Hematology in San Diego, showing the drug had activity in refractory and relapsed FLT3-ITD-positive AML when used as monotherapy. The company also shared data on the pharmacodynamic effects of quizartinib in a pooled analysis from Phase I and II studies, showing that quizartinib enhances chemotherapy in an in vivo model of AML with the FLT3-ITD mutation.

The findings suggested quizartinib was a far cry from an earlier FLT3 compound, lestaurtinib, which fizzled in summer 2009 for Cephalon Inc., of Frazer, Pa. At the time, Martino characterized the Cephalon candidate as "a fairly dirty kinase inhibitor," hitting more kinases than FLT3, while "game changer" quizartinib was specific, long-lasting and relatively safe.

Ambit had inked a deal with Cephalon in 2006 to discover and develop kinase inhibitors in exchange for up to $250.5 million in up-front and milestone payments. (See BioWorld Today, Nov. 7, 2006.)

The Cephalon failure didn't damage Ambit, and the quizartinib Phase II findings generated sufficient enthusiasm for investors to plow another $50 million into the company in November 2012. (See BioWorld Today, Nov. 7, 2012.)

Ambit, which is in a quiet period, declined comment on the proposed offering.

In its S-1, Ambit disclosed that it is developing a companion diagnostic test with Genoptix Medical Laboratory, a unit of Novartis AG, to identify FLT3-ITD-positive patients and indicated approval of the test likely "will be necessary for the approval of quizartinib." Ambit also is exploring quizartinib in other AML therapeutic settings, irrespective of FLT3-ITD status.

The company's filing reported $17.6 million in 2012 revenues from collaboration agreements and $17.5 million in cash and equivalents as of Dec. 31. The filing also indicated that Ambit has 118.4 million shares outstanding, on a pro forma weighted average basis.

Citigroup and Leerink Swann are joint book-running managers for the proposed IPO, with BMO Capital Markets acting as lead manager and Robert W. Baird & Co. Inc. acting as co-manager.