New Antibiotic Drugs on Horizon

Wednesday, September 20th 2000, 12:00 am

By: News On 6

TORONTO (AP) â€” A new family of bacteria killers on the horizon for pneumonia and other diseases should offer an alternative to standard antibiotics that have lost their punch because germs are growing resistant.

Medicines called macrolides are a standard treatment for many bacterial infections that cause respiratory diseases. They include such antibiotic warhorses as erythromycin. However, bugs like strep and staph are growing resistant to them, as well as to the primary backup medicines, known as quinolones.

The drug industry's latest salvo are the ketolides. They are derived from the macrolides, but they are chemically different, so they will kill bacteria that are resistant to macrolides.

Reports on two varieties of ketolides were presented in Toronto on Wednesday at an infectious diseases meeting sponsored by the American Society for Microbiology.

Aventis Pharmaceuticals filed with the U.S. Food and Drug Administration in March for permission to sell its new ketolide, called Ketek or telithromycin. A similar drug made by Abbott Pharmaceuticals, code named ABT-773, is also in early-stage human testing.

Researchers presented 10 separate Ketek studies at the conference involving nearly 2,500 patients. They were intended to show that once-a-day Ketek is equivalent to other standard antibiotics for treating a variety of bacterial diseases, including pneumonia, bronchitis, sinus infections and sore throats.

Macrolides work by gumming up bacteria's ability to make new proteins. Some bacteria elude the medicine by quickly pumping it out before it does any harm. Because the ketolides are chemically different, the resistant bacteria do not spit them out this way.

Jerome J. Schentag, a pharmaceutics professor at the State University of New York in Buffalo, noted that quinolone resistance is a growing worry. ``A new class of antibiotics is welcome right now,'' he said.

Dr. William Craig of the University of Wisconsin called the ketolides ``a major step'' because they give new life to the macrolides, which have long been used and have a good safety record.

Craig said that since Ketek is given for just five days, which is shorter than most antibiotics, bacteria may be less likely to grow resistant to the new drug.