There is a serious shortage of new antibiotics inthe pipeline partly because the costs involvedare too high in relation to anticipated gains. Asa result, the US FDA was allowed to approveantimicrobials on the basis of preclinical dataand preliminary studies done only on a smallnumber of patients. Between 2010 and 2015, 8new antimicrobials came into the market. Theorganisms targeted were Enterococcus faecium,Staphylococcus aureus, Klebsiella pneumonia,Acinetobacter baumanii, Pseudomonasaeruginosa and Enterobacter spp, collectivelyknown as ESKAPE.
The new drugs and their trial data are summarisedhere: Cefatroline was compared to ceftriaxoneand vancomycin- aztreonam combination in 4trials and came out non-inferior. Fidaxomicinwas compared to vancomycin in 2 trials and wasnon inferior. Bedaquiline when added to background regimen in MDR TB was found tobe superior in terms of suptum conversion butthere was a 5 fold increase of deaths.Dalbavancin was compared to vancomycin orlinezolid in two trials and was found to be noninferior. Tedizolid was compared to linezolid intwo trials and was found to be non inferior.Oritavancin was compared to vancomycin intwo trials and found to be non inferior.
The authors of the meta analysis of the new antimicrobial trials found that most trials weredesigned to show non inferiority and therefore,could not show whether the agents conferredsubstantial benefit or not. Nor were the patients'clinical outcomes analysed. While the FDA hasexpeditiously granted approval, it has disregardedits own traditional requirement of 2 trials perindication. The authors conclude that there is asof now, unclear evidence of additional benefit.
Dr. Sudip Chatterjee
Prof., Dept. of Medicine, MD. MRCP