	Industry focus on innovating within existing classes, rather than discovery of new mechanisms. The development of anti-infective medications has slowed over time, while demand for agents to meet the challenge of resistant pathogens has increased. The market potential for an antibiotic or antifungal is limited by medical concerns that extensive use of a drug exposes it to resistance. This also shortens the marketable life of an agent, as resistance develops over time. Given the extensive time and financial investment required to develop any new agent, a conservative option is to focus on improving on current classes. This choice also plays to physicians’ comfort with familiar classes, which may motivate prescribing. Since the launch of novel agents Zyvox® and Cubicin® in recent years, the remaining pipeline has consisted of familiar favorites, glycopeptides and cephalosporins. In the antifungal space, as well, the pipeline consists mainly of triazoles and echinocandins, rather than newer mechanisms.

	*Physician preference for targeted vs. broad-spectrum therapies. In order to manage resistance of pathogens to available treatments, hospital authorities recommend physicians treat infections with the most specific agents available. As most bacterial infections are gram-positive, physicians are not likely to initiate* treatment with a broad-spectrum agent, such as Wyeth’s Tygacil®, out of a concern that unnecessary use may breed resistant gram-negative bugs. Thus, such medications are often reserved for documented polymicrobial infections, such as diabetic foot infections. As such, targeted gram-positive agents have greater overall market potential than broad-spectrum agents.