As part of my reporting workload in recent months, I’ve been navigating the vast, little-known world of antibiotic alternatives. Among the most intriguing are phages, naturally-occurring viruses that have evolved to kill bacteria—and that make mincemeat of even the staunchest antibiotic-resistant species. My piece in the last issue of Popular Science magazine profiled Randy Wolcott, a doctor in Texas who is investigating ways to get phages approved in the United States. And for a graphics-based roundup in May’s Fast Company, I profiled NovaBay and PolyMedix—two companies investigating chemical compounds that physically disable bacteria—as well as Intralytix, the US-based phage company Wolcott has been working with.

What I haven’t gotten a handle on is why these pharmacological alternatives have yet to take off in a big way. The antibiotic resistance problem is getting worse; as I mention in the Fast Company piece, 70% of infections are resistant to at least one antibiotic, forcing many doctors to prescribe expensive antibiotic cocktails to vanquish ever-wilier bacteria. Yet antibiotic-alternative companies have hit various roadblocks in their quest to bring a finished product to the marketplace. One reason may be that companies operating at the bleeding edge of biotech tend to be small and scrappy, making it a financial stretch to pull together the resources needed to shepherd a new therapy through multi-stage clinical trials. What do you think? On the face of it, these companies are rushing in to fill a very obvious vacuum, so why is quick success elusive?