Drugmaker Merck says it will no longer manufacture or market the antibacterial combination drug Recarbrio in the United States.
A combination of the antibiotic imipenem-cilastatin and the beta-lactamase inhibitor relebactam, Recarbrio was approved by the US Food and Drug Administration (FDA) in 2019 to treat adults with complicated urinary tract infections and intra-abdominal infections and no alternative treatment options. It was approved for adults with hospital-acquired and ventilator-associated bacterial pneumonia in 2020 and expanded for use in children in 2025.
Recarbrio was developed to target multidrug-resistant infections, particularly pathogens carrying resistance mechanisms that can disable beta-lactam antibiotics, like Klebsiella pneumoniae carbapenemase (KPC), which is found in carbapenem-resistant Enterobacterales (CRE) infections. It’s one of several beta-lactam/beta-lactamase inhibitor combinations that have been developed in recent years to meet the rising threat of drug-resistant bacteria and was initially touted by the company as an important new tool for patients with difficult-to-treat infections.
"At a time of great public health concern about the need for new treatments to meet the evolving challenges posed by Gram-negative bacteria, we are proud to continue bringing new therapeutic options to health care practitioners in an effort to help them overcome the challenges in patient care,” Nicholas Kartsonis, MD, senior vice president of clinical research, infectious diseases and vaccines at Merck Research Laboratories, said in a 2020 press release.
The company said the decision to withdraw the drug from the US market came as part of an ongoing review of its portfolio and was not related to any product safety or quality issues.
Clinical gap ‘immediate but narrow’
“We understand that Recarbrio has been an important option for certain patients. Alternative therapeutic options remain available for the approved indications; patients should consult their healthcare provider to determine the appropriate course of action,” a Merck spokesperson told CIDRAP News.
Amesh Adalja, MD, an infectious disease physician and senior scholar with the Johns Hopkins University Center for Health Security, said the clinical gap left by the discontinuation of Recarbrio is “immediate but narrow.”
“For KPC-producing CRE, the resistance relebactam was designed to overcome, we still have drugs like ceftazidime-avibactam, meropenem-vaborbactam, and cefiderocol. The loss will be felt most with difficult-to-treat Pseudomonas aeruginosa, where imipenem-relebactam was one of a short list of preferred options,” Adalja said.
But Brad Spellberg, MD, chief medical officer at the Los Angeles General Medical Center, said he’s not surprised, given that the drug is “not in any way meaningfully differentiated from multiple other drugs on the market.” Spellberg was skeptical about Recarbrio before it was even approved.
“This drug was never going to be used,” Spellberg said.
Concerns about market failure
For others, the move raises more questions about the viability of the market for new antibiotics. Because the population of patients with multidrug-resistant infections and no alternative treatment options is limited, and antibiotic stewardship programs are required in US hospitals, most new antibiotics are used infrequently.
“We appropriately reserve new antibiotics for patients who truly need them, but that means these medicines will sit on the shelf for long periods and generate little revenue,” said Henry Skinner, PhD, CEO of the AMR Action Fund.
We appropriately reserve new antibiotics for patients who truly need them, but that means these medicines will sit on the shelf for long periods and generate little revenue.
Skinner said he’s particularly concerned about the implications for pediatric patients with multidrug-resistant infections. Citing a 2025 study published in the journal Antibiotics, he noted that the small-to-midsize pharmaceutical companies that currently drive antibiotic development completed only 10% of required pediatric post-approval studies, which are needed to expand drug labels for pediatric use, and none received pediatric approvals for their products.
“Merck did the long, costly work required to fulfill a pediatric postmarketing requirement and expand Recarbrio’s label to children weighing as little as 2 kilograms,” Skinner said. “If large companies cannot sustain these products on the market, who will generate the evidence needed to bring future antibiotics to children?”
Both Skinner and Adalja said they believe a fix could be provided by the PASTEUR Act, a bill that would establish a new payment model for new antibiotics, under which companies would receive fixed annual payments from the federal government for novel new antibiotics.
“Until it or something like it becomes policy, more exits like this will come, which means fewer new antibiotics,” Adalja said.
Though the legislation has received bipartisan support since it was first introduced in Congress in 2020, it has yet to pass.
