Biotech firm Anacor Pharmaceuticals has withdrawn its filing to go public after an arduous 16-month wait (unprecedented for health care enterprises, reports VentureWire). The Palo Alto, Calif.-based company says the market is not optimal to hit its target of $57.5 million in the sale.

Anacor, currently working on a therapy to treat nail fungal infections, had earmarked $49 million of that sum for further research and development of its lead drug candidate. It had already struck licensing deals with Schering-Plough and GlaxoSmithKline in this pursuit. While it has yet to bring in revenue in its six years, the company has raised $37 million to date from Rho Capital Partners, Venrock, Care Capital and Aberdare Ventures.

This brings the total number of companies canceling IPOs due to economic conditions this year to 42.