Off-label Use of Recently-Approved Antimicrobial Agents Is Common

Study results indicate that clinicians start prescribing new drugs off-label almost as soon as the drugs become available.

A retrospective look at the recent pattern of use of antimicrobial agents in several hospitals in Pittsburgh, Pennsylvania, has provided solid evidence that clinicians start prescribing new drugs off-label (ie, not necessarily for their US Food and Drug Administration (FDA)-approved use) almost as soon as the drug becomes available.

“Given the frequent use of novel gram-negative agents for pneumonia, there is a need for early trials to determine their role for this indication. In the meantime, antimicrobial stewardship program should consider off-label indications such as pneumonia when developing local criteria for use,” wrote the researchers.

The data presented at a Poster Abstract Session at ID Week 2018 being held here in San Francisco, California, substantiate the concern over the use of antimicrobial agents without robust antimicrobial stewardship.

The results of a survey of 6 hospitals (50-350 beds) starting in 2014 revealed the use of antimicrobial agents within 1 to 2 years of FDA approval. Topping the list was oritavancin, which was in use in all 6 hospitals within 25 months of approval. The drug was approved in early September 2014 for the treatment of acute bacterial skin and soft tissue infections (ABSSSIs) caused by gram-positive bacteria, including methicillin-resistant Staphylococcus aureus and vancomycin-intermediate S aureus. It was used as recommended for 80% of patients with these infections; however, off-label use included bacteremia (11% of patients), osteomyelitis (14% of patients) and other infections.

Ceftazidine-avibactam received approval in late February 2015 for the treatment of complicated urinary tract infection and complicated intra-abdominal infection caused by gram-negative bacteria. Although used for these infections, off-label use was more than twice as common (30% vs 77%), and included the treatment of pneumonia (35% of patients), osteomyelitis (35%), as well as bacteremia and sepsis.

Other drugs that were surveyed were dalbavancin, tedizolid, ceftolozane-tazobactam, peramivir, and isavuconazole. Delafloxacin, meropenem-vaborbactam, and letermovir did not make the list, as they had only been very recently approved at the time of the study and so did not have a sufficient track record of use.

The mean time from FDA approval to the time the drug was pressed into service ranged from 12 months for tedizolid to 26 months for dalbavancin. Approved use ranged from only 7% for ceftolozane-tazobactam for complicated urinary tract infection to 100% for tedizolid for ABSSSI. Empiric use mostly concerned gram-positive bacteria, with gram-negative bacteria tending to be specifically targeted.

The finding of off-label use of drugs is not a shocker. Antimicrobial agents are often used for indications not approved by the FDA. “While this can be appropriate at times, they may be used in settings with no published experience,” according to the presenters.

The poster presenter was Tina Kadem, PharmD, University of Pittsburgh Medical Center Presbyterian Hospital.

DISCLOSURES

Tina Khadem, PharmD: None

PRESENTATIONS

Poster Session: Antimicrobial Stewardship: Potpourri

Tina Khadem, PharmD

University of Pittsburgh Medical Center Presbyterian Hospital

Poster 1880. Does the label matter: Initial use of newly approved antimicrobial agents in community hospitals without robust antimicrobial stewardship programs.

Brian Hoyle, PhD, is a medical and science writer and editor from Halifax, Nova Scotia, Canada. He has been a full-time freelance writer/editor for over 15 years. Prior to that, he was a research microbiologist and lab manager of a provincial government water testing lab. He can be reached at hoyle@square-rainbow.com.