Discovery of gemifloxacin (Factive, LB20304a): a quinolone of a new generation

Novel Quinolone antibacterials, which bear an alkyloxime substituent in the 4-position and an aminomethyl substituent in the 3-position of the pyrrolidine ring, have been designed and synthesized. These fluoroquinolones were found to possess extremely potent antimicrobial activity against gram-positive organisms including resistant strains such as methicillin-resistant Staphylococcus aureus (MRSA). Among these compounds our development candidate, Gemifloxacin (Factive, LB20304a), showed the best in vivo efficacy and pharmacokinetic profile in Animals, as well as good safety pharmacological properties. Gemifloxacin was found to be especially effective against respiratory tract infections that account for over 70% of all infections. With once-a-day dosage, potency against respiratory tract infections such as chronic bronchitis and pneumonia was ensured without any significant side effect. In December 1999, Gemifloxacin filed a NDA for marketing approval to the US Food and Drug Administration.