WARNER-LAMBERT’s SPARFLOXACIN FOR MAI INFECTIONS IS REENTERING CLINICALS

WARNER-LAMBERT's SPARFLOXACIN FOR MAI INFECTIONS IS REENTERING CLINICALS through a Phase I/II trial at three investigative sites with six patients each. Last June, the fluorquinolone entered a 14-site, 45-patient clinical trial for the treatment of the AIDS- related opportunistic infection Mycobacterium avium intracellular (MAI, or MA complex, MAC), but Warner-Lambert said the trial was halted in November because of a "possibly drug-related adverse effect" in one patient. Sparfloxacin, a newer generation quinolone, is licensed by Warner-Lambert from the Japanese pharmaceutical firm Dainippon. The drug currently is also in Phase III trials as an antibacterial for the treatment of skin infections, pneumonia, bronchitis and complicated urinary tract infections. Sparfloxacin was one of several new drugs discussed at a Feb. 26 National Institutes of Health clinical staff conference on "Recent Advances in the Treatment of AIDS-Related Opportunistic Infections." Others included a fluorquinolone from Sterling's Winthrop Pharmaceutical, two Walter Reed Army Institute of Research compounds for Pneumocystis carinii pneumonia and two Merck candidates for PCP. Robert Davey, Jr., MD, a senior investigator at the National Institute of Allergy and Infectious Diseases' Immunoregulation Lab, commented that sparfloxacin has been found "to exhibit significant activity" against MAI. In in vitro models of MAI growth, Davey said, "the MAIs with sparfloxacin have generally been substantially lower than with Cipro" (Miles' ciprofloxacin). He added that sparfloxacin also shows "synergistic activity with two conventional anti-MAI agents, ethambucol and rifampin." NIAID Developmental Therapeutic Branch senior scientist Barbara Laughon, MD, reported that another fluorquinolone, Winthrop's WIN 57273, also has shown "promising in vitro and animal efficacy data" against MAI. The company is developing the drug as a candidate for outlicensing and has no plans for clinical trials. Two new drugs of the 8-aminoquinoline class are expected to enter clinical trials shortly for treatment and prophylaxis of PCP, Laughon reported. Developed by the Walter Reed Army Institute of Research, WR 6026 and WR 238,605 both have shown promise against malaria in preclinical trials. FDA has approved the PCP protocol for WR 6026, and the protocol for WR 238,605 is pending at the agency. The two Merck candidate compounds for PCP, L-688,786 and L- 693,989, "may be most useful for long-term prophylaxis," Laughon commented. Merck said the compounds are not yet at the drug development stage and have not entered animal toxicity trials.