SAN FRANCISCO — Two head-to-head comparison trials of micafungin found that it was as effective as older antifungals in treating invasive candidiasis, according to presentations at the annual Interscience Conference on Antimicrobial Agents and Chemotherapy.
Micafungin, a member of the class known as echinocandins, was approved in the United States in 2005 for treatment of esophageal candidiasis and for prophylactic treatment of patients undergoing bone marrow transplantation.
Intravenous micafungin at two different doses produced cure rates similar to those with caspofungin in an international trial with 593 adults who had candidemia or invasive candidiasis, said Dr. Robert Betts, a professor of medicine at the University of Rochester, New York.
The cure rates overall were 74% for the lower dose of micafungin (100 mg/day), 70% for the more typical dose (150 mg/day), and 71% for caspofungin, which was given as a 70-mg loading dose on the first day followed by 50 mg/day.
There were no significant differences between the treatments in adverse events, treatment discontinuation, or relapse, Dr. Betts said.
The only significant difference was in the treatment of patients with invasive candidiasis, for whom the lower dose of micafungin was more effective than the higher dose, with a cure rate of 75%, compared with 53%. By comparison, the caspofungin cure rate was 65% for invasive candidiasis.
Some nonsignificant differences were found for species of Candida other than Candida albicans: Caspofungin performed slightly better against C. tropicalis (75% success vs. 68%), and micafungin performed better against C. glabrata (86% vs. 67%) and C. parapsilosis (77% vs. 64%). Those results may deserve further investigation, Dr. Betts said.
“Micafungin at 100 mg a day appears to be the optimal dose in the treatment of invasive candidiasis or candidemia,” he said.
In the second study, micafungin was compared with liposomal amphotericin B in 98 children with Candida infection, 91% of whom had candidemia.
Micafungin had an overall success rate of 72%, compared with 76% for liposomal amphotericin B. In patients with neutropenia, micafungin was effective in 85%, compared with 77% for amphotericin B. Neither of these differences was statistically significant, said Dr. Antonio Arrieta, an infectious disease specialist at Children's Hospital Orange County, Orange, Calif.
The majority of patients had a Candida infection other than C. albicans; the most common other species was C. parapsilosis. Micafungin treatment was successful in 80% of patients with C. parapsilosis, compared with 60% for liposomal amphotericin B, a difference that was not statistically significant.
No differences in treatment were found between children less than 2 years of age and older children, but the differences observed were mainly in the adverse effects, Dr. Arrieta said. Serious adverse events occurred in 4% of the patients treated with micafungin and 9% of the patients treated with liposomal amphotericin B. “I think the safety of [micafungin] is what has changed my practice,” Dr. Arrieta said in an interview at the meeting.
Both studies were sponsored by the manufacturer of micafungin, Astellas Pharma.