A New Jersey biotech firm with a promising treatment for serious skin infections is moving its headquarters to downtown Chicago. In the latest tech win for downtown, Morristown, N.J.-based Durata Therapeutics Inc. intends to set up shop at 200 S. Wacker Drive by year-end, Gov. Pat Quinn and company officials are announcing this morning. The company has only a couple of dozen employees. But it said it expects to increase that to 100 within three years, particularly if its new drug, Dalbavancin, wins approval by the U.S. Food and Drug Administration. Dalbavancin now is in Phase 3 clinical trials — the last step prior to requesting the final federal OK. The drug is aimed at giving physicians and hospitals another weapon against an epidemic of hard-to-treat skin infections that often spread in institutional settings. The company will receive up to $2 million in state Edge payroll tax credits over 10 years, providing that it maintains a staff of at least 25 here. Right now, the company has no Illinois-based employees. The move to Chicago will be a bit of a homecoming for some of the company’s senior executives. CEO Paul Edick was an official with the old G.D. Searle, now a part of Pfizer Inc., and Chief Commercial Officer John Shannon worked at Searle and at Baxter International Inc.