LONDON – "This window really is unique: It's supporting relatively early stage stories and especially platform technology stories."

So said Tim Van Hauwermeiren, CEO of antibody specialist Argen-x BV, speaking from San Francisco, where he is drumming up interest for the company's initial public offering (IPO) and listing on Euronext Brussels.

"It's got off to a good start. We are aiming to raise €40 million to €50 million (US$54.5 million to $68.1 million) and have €22 million booked already," Van Hauwermeiren told Bioworld Today.

Although it's not clear at this stage what percentage of shares will be taken up by U.S. institutional investors, the reason to go for an IPO was strong demand from the U.S. "We wouldn't have done it without U.S. support," Van Hauwermeiren said.

Ghent, Belgium-based Argen-x is offering up to €40 million in new shares, which may be increased by a maximum of 15 percent up to €46 million. The price range is €8.50 to €10.25 per share.

As part of a rare diseases antibody discovery and development alliance with Shire plc, which was expanded to include a third program at the end of May, Shire is investing €12 million in the IPO. A further €10 million has been booked by existing investors, who include the premier U.S. investor Orbimed Advisors LLC, of New York. Those current investors have agreed to a one-year lock-up.

Van Hauwermeiren is sanguine about Abbvie Inc.'s $47 billion bid to buy Shire, which became public last Friday. "It's not new really. Shire has been rumored as a possible takeover candidate for some time," he said. (See BioWorld Today, June 23, 2014.)

Pre-IPO, Argen-x is in pretty good shape for a small privately funded biotech, with €20 million in cash. The new money will be used to further advance the first three products with the aim of providing enough data for partnering deals.

"We are going to be lighting more fires in the clinic, to position the lead programs for commercialization in a number of indications," Van Hauwermeiren said.

The programs arise from an antibody platform, called SIMPLE, which is derived from the variable regions of the conventional antibody repertoire found in camelids (llamas and camels). That is distinct from the heavy-chain-only antibody repertoire, also found in camelids, which Ghent, Belgium-based Ablynx NV is exploiting.

Conventional camelid V-domains are indistinguishable from those found in human antibodies. Those V-domains are fused with human antibody backbones (the Fc domains of camelid antibodies are not human-like) to form what are essentially fully human antibodies. Argen-x has positioned the technology as an unencumbered platform that can generate high-affinity antibodies against difficult targets.

The lead antibody, ARGX-110, targeting the immune checkpoint target CD70, is being tested in a range of hematological and solid tumors in a phase 1b trial. Argen-x claims a triple mode of action, with the product blocking growth of new cancer cells, destroying existing ones and activating the patient's immune system against the tumor.

Two weeks ago, Argen-x signed an agreement with the Leukemia and Lymphoma Society (LLS), of White Plains, New York, in which the two parties agreed to contribute up to $2.2 million each to fund a phase II study of ARGX-110 in the rare blood cancer Waldenstrom's macroglobulinema (WM).

Lee Greenberger, chief scientific officer of LLS, said recent research has dramatically increased understanding of the role of CD70 in WM. "Based on preclinical and initial clinical data . . . we believe ARHX-110 has potential to benefit patients with WM," Greenberger said.

For Argen-x, the deal allows it to work with leading U.S. cancer centers. It plans to submit an investigational new drug application later in the year, with the trial due to start at Harvard Medical School in Cambridge, Mass., before the end of 2014.

"The phase II deal with LLS is simply a great evolution for us," Van Hauwermeiren said.

The second product, ARGX-111, targeting c-MET, a tyrosine kinase receptor which is involved in metastasis, also is in phase Ib, while ARGX-113, an antibody fragment designed to treat severe autoimmune diseases is in late preclinical development.

U.S. QUEUE GETTING LONGER

While Argen-x aims to join the handful of other firms listing on European markets this year – among those were Circassia Pharmaceuticals plc, Horizon Discovery Group and Txcell SA – four more biotechs filed S-1s with the SEC Tuesday to go public on Nasdaq. All four filed as emerging growth companies under the Jumpstart Our Business Startups Act.

Immune Design Corp., of Seattle, filed for a potential $60 million IPO to support clinical development of CMB305 and G100, as well as for working capital and general corporate purposes. CMB305, which uses the firm's prime-boost approach combining LV305 with G305 – those drugs emerged from the firm's Dcvex and GLAAS platforms, respectively – is set to start a phase I trial in a subset of tumor types studied in early individual trials of LV305 and G305. The immunotherapy firm also recently began a phase I trial with LV305 in solid tumors, with safety and immunogenicity data expected in the first quarter of 2015. As of March 31, Immune Design had about $25 million in cash, having raised $49 million in a series C round last year, with investors including Topspin Partners, the Column Group, Sanofi-Genzyme Bioventures, Alta Partners, Versant Ventures, Osage Partners and Proquest Investments. The company has not yet disclosed the share price or number of shares to be offered in the IPO. Jefferies, Leerink Swann and Wells Fargo are acting as underwriters. Immune Design plans to seek a listing under the ticker IMDZ. (See BioWorld Today, Oct. 31, 2014.)

Macrocure Ltd., of Petach Tikva, Israel, filed an F-1 with the SEC for a proposed $75 million IPO, though the number of shares and share price have not yet been disclosed. The regenerative medicine firm, which aims to list on Nasdaq under the ticker MCUR, said it will use proceeds to support late-stage clinical development and regulatory activities for Curexcell, an advanced wound care therapy currently in two phase III trials for diabetic foot ulcers (DFUs) and venous leg ulcers (VLUs). Results from the DFU trial and interim data from the VLU study are expected in the second half of 2015. Macrocure said proceeds from the IPO should be sufficient to finish the phase III trials, seek regulatory approval and complete necessary manufacturing for commercialization. The company's primary stockholders include Portifax, Viola Partners, Kuf Dalet and Vaizra Ventures. As of March 31, it had about $16 million on its balance sheet. Credit-Suisse, Jefferies, Oppenheimer and Nomura are acting as underwriters for the proposed IPO. (See BioWorld Today, June 20, 2013.)

Tobira Therapeutics Inc., of South San Francisco, filed for an IPO, hoping to raise $69 million, though the number of shares and share price were not disclosed. Proceeds will be used to fund further development of lead candidate cenicriviroc (CVC), an immunomodulator, including a phase II study expected to start in the second half of this year in nonalcoholic steatohepatitis and testing in other immuno-inflammatory and fibrosis indications. Tobira also has plans to expand CVC, designed to work by inhibiting chemokine receptor type 2 (CCR2) and CCR5, in a fixed-dose combination for HIV-1 infection, though the firm aims to advance that program via a strategic collaboration. Tobira last raised money in 2010, in a $31 million series B round led by new investor Novo A/S, with existing investors Domain Associates LLC, Frazier Healthcare Ventures, Montreux Equity Partners and Canaan Partners. As of March 31, the firm had about $9.8 million in cash and equivalents. BMO Capital Markets, JMP Securities, Oppenheimer and Nomura are serving as underwriters for the proposed IPO. Upon pricing, Tobira seeks a listing under the ticker TBRA. (See BioWorld Today, Sept. 30, 2010.)

Zosano Pharma Inc., of Fremont, Calif., filed for a proposed $65 million IPO, with proceeds expected to support a phase II trial of weekly ZP-PTH, its version of parathyroid hormone teriparatide formulated with its microneedle patch delivery system, for treating severe osteoporosis. Funds also will support phase II and phase III trials of its ZP-Glucagon candidate for severe hypoglycemia and further R&D work for ZP-Triptan in migraine. Zosano's investors include BMV Direct and New Enterprise Associates, and the firm ended the first quarter with $5.6 million in cash. The number of shares and share price for the IPO have not yet been disclosed. Zosano seeks to list on Nasdaq under the symbol ZSAN. Wedbush Pacgrow Life Sciences, Ladenburg Thalmann and Roth Capital are acting as underwriters.