Pliva gains FDA approval for generic antibiotic

Azithromycin is the AB-rated generic equivalent of Pfizer’s Zithromax, an antibiotic indicated for the treatment of patients with mild to moderate infections caused by susceptible strains of bacteria. It is most often used to treat respiratory infections but can also be used to treat skin infections and some sexually transmitted diseases.

Originally discovered by Pliva, azithromycin was licensed to Pfizer in 1986 for exclusive sale in the US and Western Europe. The drug brought in substantial royalty revenue for Pliva, but this revenue has now dissolved with the expiry of Pliva’s patent at the beginning of November 2005.

Although Pliva is hoping to offset declines in royalty revenues by developing a strong generic business, its efforts may be hampered to some degree by the FDA’s approval of other generic versions of Zithromax. Both Israel’s Teva Pharmaceutical Industries and Novartis AG’s Sandoz unit have received approval to market different strength versions of azithromycin.

Pliva’s previous earnings associated with azithromycin are estimated to be as much as $150 million a year. Analysts are predicting further positive sales results for its new strength versions of the drug, 250 mg, 500 mg and 600 mg, as they cover a broader spectrum than Zithromax. However, Pfizer is reportedly planning to develop injection and liquid solution formulations of the drug.