US-based Rib-X Pharmaceuticals Inc, a developer of antibiotics, has withdrawn registration for an $80m IPO, which had a market capitalization of $112m. It originally filed for the offering last year, but postponed it back in May. Rib-X set the price range for its initial public offering at between $12 and $14 for each of the 5.77 million shares that were to be sold.
Rib-X recently announced that it has closed a $18.7m first tranche of a $67.5m preferred stock round of financing led by Vatera Healthcare Partners, and were joined by return backers Warburg Pincus, ABS Ventures and Vox Equity Partners. A second tranche is expected to close by the end of the year.
Shareholders in Rib-X include SR One, the corporate venturing unit belonging to healthcare conglomerate GlaxoSmithKline which holds 7.4% of Rib-X’s common stock and MedImmune Ventures, a corporate venture fund operated by pharmaceuticals company AstraZeneca (which holds 6.0%).
Also holding stock in Rib-X are private equity (PE) firm Warburg Pincus (45%), and venture capital (VC) firms Saints Capital (23.1%), Oxford Biosciences Partners (13.9%) and Cardinal Partners (5.4%).
Rib-X has raised around $160m since 2002.