Optimer’s Second Drug, for Traveler’s Diarrhea, Follows Fast Behind Lead “C. Diff” Antibiotic

San Diego’s Optimer Pharmaceuticals had its breakout moment in November, when it showed its experimental drug could wipe out the dreaded C. Diff bacteria, a horrific, sometimes fatal form of diarrhea that people sometimes pick up in the hospital. What fewer people realize is Optimer (NASDAQ: [[ticker:OPTR]]) has another anti-diarrhea drug in the works that’s designed to stop the milder forms of diarrhea that Americans tend to get when they travel to developing countries.

Optimer’s second drug candidate is called prulifloxacin. It’s part of a class of antibiotics known as fluoroquinolones, and it is commercially available in Japan and Korea in an intravenous form. Optimer’s trick is to make it into an oral form, taken once-a-day for three straight days, which ought to stop a variety of different bugs from making people get so sick that it ruins their vacation.

People currently take Bayer’s ciprofloxacin (Cipro) for traveler’s diarrhea, but Optimer’s drug is more potent and hopes to grab much of the market share, says Optimer CEO Michael Chang. The Bayer drug is in the same class, but has to be taken twice a day for five days, which means patients find it hard to comply with the schedule, says Optimer chief commercial officer Kevin Poulos. It’s also not well-tolerated when people spend time in the sun, which can really sap the fun out of your vacation. This isn’t a huge market—about $200 million are up for grabs—but Optimer thinks it can carve out a strong niche to diversify its sources of revenue in the future, Poulos says.

“This will be the most convenient, and most potent antibiotic for infectious diarrhea approved by FDA, if it’s approved,” Poulos says. “It’s a small market compared to other indications, but the beauty of it is that it’s a market that hasn’t had a lot of attention paid to it. We consider that as an advantage. I’d rather enter a market where we have a unique advantage, instead of a market that’s crowded, like respiratory antibiotics. We feel we can get a large share in a small market, versus a small share in a bigger market.”

The drug has already passed one clinical trial it needs to include in an application for FDA approval, and it expects to get results from a second required trial before the end of March, Chang says. If that goes well, the company will file for FDA approval of prulifloxacin before the end of the year.

This drug isn’t meant to be taken as a preventive treatment; instead patients would wait until they feel a touch of diarrhea coming on, and then take the pill, Chang says. It’s supposed to work fast, so a patient could take it and have their diarrhea go away within 24 hours, he says. About 80 percent got relief from their diarrhea, compared with 40 percent who took placebo. If patients didn’t have their diarrhea improve within the first day, they were able to get a standard treatment to take care of it, Chang says.

The first trial tested the Optimer drug in Mexico and Peru, where it was largely up against E. Coli. The second trial was in India, Guatemala, and Mexico, where the drug mainly had to fight shigella, Chang says. “That way we can cover more people traveling to different parts of the world,” Chang says.

If all goes according to plan, this drug will arrive on the market about the same time in 2010 as Optimer’s other drug, OPT-80, for “C. Diff” bacteria. That drug, which still needs to pass one more clinical trial this year, was recently given the generic name of fidaxomicin. One big event on Optimer’s to-do list this year will be forming a partnership outside the U.S. to help with marketing fidaxomicin, while keeping control of it in the U.S.

“The value driver for Optimer is fidaxomicin, the ratio is about 80/20,” Chang says. “But this second drug (prulifloxacin) is going to be the best-in-class, we think, and has reasonable potential to be a good earnings contributor.”

Author: Luke Timmerman

Luke is an award-winning journalist specializing in life sciences. He has served as national biotechnology editor for Xconomy and national biotechnology reporter for Bloomberg News. Luke got started covering life sciences at The Seattle Times, where he was the lead reporter on an investigation of doctors who leaked confidential information about clinical trials to investors. The story won the Scripps Howard National Journalism Award and several other national prizes. Luke holds a bachelor’s degree in journalism from the University of Wisconsin-Madison, and during the 2005-2006 academic year, he was a Knight Science Journalism Fellow at MIT.