On May 2nd, 2018 the Antimicrobial Drugs Advisory Committee convened to review new drug application (NDA) 210303, for plazomicin, sponsored by Achaogen Inc. Plazomicin is an aminoglycoside antibacterial drug proposed for in the treatment of complicated urinary tract infections (cUTI) and blood stream infections (BSI) in patients 18 years or older, with limited or no alternative treatments. Plazomicin produces a concentration-dependent bactericidal effect through the inhibition of protein synthesis. The proposed starting doses were 15 mg/kg daily for patients with creatinine clearance (Clcr) of greater than 60 mL/min; 10 mg/kg daily for those with Clcr 30 – 60 mL/min and 10 mg/kg every other day for those with CLcr 15 – 30 mL/min.
Plazomicin was evaluated in six phase I studies , one phase II study and one phase III clinical study. The phase II study and one phase III study were conducted for cUTI. The medication was deemed to be non-inferior to a comparable antibiotic in the cUTI study.
There were 2 voting questions presented to the panel. First, the panelists were asked whether the applicant provided substantial evidence of the safety and efficacy of plazomicin for cUTI in patients with limited to no treatment options – voting 15 (Yes) to 0 (No). Unanimously, the panel indicated that animal studies supported efficacy and clinical data did not show a pattern of serious adverse events. The panel also recommended post marketing safety studies and labeling to provide guidance for therapeutic drug monitoring.
During the second vote, the panel was asked whether the safety and efficacy data presented for plazomicin were adequate for BSI. The committee voted 4 (Yes) to 11 (No). Members who voted yes, said that the study showed some efficacy and safety for those with limited or no treatment options. Members who voted no, were concerned with the very small sample size and inadequacy of the non-inferiority analysis as a basis for approval.
The agency is not obligated to follow its panel’s recommendation, but normally does so. On June 26th plazomicin was approved for cUTI treatment by the FDA. The BSI indication was not approved.
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This post was authored by Sami Mourad. Sami is a summer intern at ISS and a 3rd year pharmacy student at the Rutgers University Ernest Mario School of Pharmacy