Merck has announced that it will no longer manufacture or market the antibacterial combination drug Recarbrio in the U.S. CIDRAP has the news.

Recarbrio is a combination of the antibiotic imipenem-cilastatin and the beta-lactamase inhibitor relebactam. It was approved by the FDA in 2019 to treat adults with complicated UTIs and intra-abdominal infections with no alternative treatment options. It was also approved for adults with hospital-acquired and ventilator-associated bacterial pneumonia in 2020.

The drug was developed to treat multidrug-resistant infections, and particularly pathogens that carry resistance mechanisms that can disable beta-lactam antibiotics. It was initially touted by Merck as an important new tool for patients with difficult-to-treat infections. They said the decision to withdraw the drug from the U.S. market came as part of an ongoing review of its portfolio and wasn’t related to product safety or quality issues.

Experts were split on the drug itself. One expert said that there are already other drugs that treat the resistance relebactam was designed to overcome, but its absence will still be felt, like with difficult-to-treat Pseudomonas aeruginosa. Others said they felt the drug was never going to be used due to its lack of meaningful differentiation from other drugs on the market. Others, meanwhile, said the move raises questions about the viability of the market for new antibiotics.