Test Drug Does Well Against Hospital Infection
A new antibiotic being developed by a small San Diego company fared well in a clinical trial, holding promise in treating an intestinal superbug that is commonly spread in hospitals and is becoming more deadly.
In the trial, the drug developed by Optimer Pharmaceuticals to treat a bacterium, Clostridium difficile, worked better than the only approved drug on the market.
The bacterium kills thousands of Americans a year, and that number has been rising sharply, in part because a more virulent strain has emerged.
The announcement led Optimer’s stock price to nearly double in after-hours trading; it closed at $8.50, up $3.90, or 84.78 percent.
The results could also represent a significant step in the fight against the superbug, which can cause severe diarrhea and in some cases requires the removal of the colon.
“C. difficile, if you look at the numbers, probably far outstrips MRSA as a hospital-acquired problem,” said Dr. Stuart Johnson, an associate professor at Stritch School of Medicine at Loyola University. The usual treatment for C. difficile infection is the generic antibiotic metronidazole. More serious cases are treated with the approved drug, Vancocin, a branded oral version of the antibiotic vancomycin that is sold by ViroPharma.
But more than 20 percent of patients treated with either drug have relapses that often require hospitalization again, said Dr. Johnson, who is a consultant to Optimer and other companies.
In the clinical trial, both Optimer’s drug and Vancocin were nearly 90 percent effective in initially clearing the infection. But only 15.4 percent of those treated with Optimer’s drug, called OPT-80, suffered a relapse within four weeks, compared with 25.3 percent of those treated with Vancocin.
The difference in recurrence rates “is something that has us absolutely ecstatic,” Pam Sears, senior director for biology at Optimer, told analysts on a conference call.
The longer-term cure rate, meaning initial cure without recurrence, was 74.6 percent for OPT-80 compared with 64.1 percent for Vancocin.
The study, sponsored by Optimer, involved 629 patients in the United States and Canada. It was a Phase 3 trial, the final stage of testing before a drug is approved. Optimer said it would complete another Phase 3 trial, with results expected late next year, before applying to the Food and Drug Administration for approval to market the drug.
Optimer has no drugs on the market yet but has another antibiotic for travelers’ diarrhea that is also in Phase 3 clinical trials.
ViroPharma recorded Vancocin sales of $182.3 million for the first nine months of 2008, up 17 percent from the year earlier, and the drug is responsible for the company being profitable.
ViroPharma, based in Exton, Pa., acquired Vancocin from Eli Lilly & Company in 2004, just as concerns over C. difficile started to rise, then increased the price of the drug 80 percent in its first year of ownership.
In after-hours trading Monday, ViroPharma’s stock was down $1.07, to $11.50.
C. difficile infection occurs when patients are treated with antibiotics for other problems. The antibiotic treatment disrupts the bacteria in the intestine, allowing C. difficile, which is resistant to many antibiotics, to take over.
Last week, Medarex and the University of Massachusetts said that antibodies they were developing to neutralize toxins produced by C. difficile had been effective in a Phase 2, or midstage, clinical trial.