Meiji Seika Pharma: Results from the Global Phase III Trial (Integral-2) of Nacubactam, a Novel β-Lactamase Inhibitor, Highlighted in The Lancet Microbe ’s Coverage of ESCMID Global Congress 2026

Meiji Seika Pharma Co., Ltd. (Headquarters: Tokyo, President and Representative Director: Toshiaki Nagasato) today announced that results from the global Phase III trial (Integral-2) of nacubactam (Development Code: OP0595), a novel β-lactamase inhibitor, were highlighted in The Lancet Microbe’s coverage of ESCMID Global Congress 2026 (held in Munich, Germany).

As highlighted in The Lancet Microbe’s coverage, the key findings presented by Meiji Seika Pharma at ESCMID Global Congress 2026 are as follows:

The Integral-2 study (jRCT2031230076) is a global Phase III clinical trial that enrolled patients with complicated urinary tract infections, acute uncomplicated pyelonephritis, hospital-acquired bacterial pneumonia, ventilator-associated bacterial pneumonia, or complicated intra-abdominal infections caused by carbapenem-resistant Gram-negative bacteria (excluding Acinetobacter species). The study has achieved the prespecified study objectives. For the primary endpoint of overall treatment success at seven days after the end of treatment, cefepime/nacubactam and aztreonam/nacubactam showed success rates of 44.4% (12/27 patients) and 50.0% (12/24 patients), respectively; for reference, the success rate with Best Available Therapy (BAT) was 26.1% (6/23 patients). No major clinical safety concerns were observed.

For background, nacubactam is a β-lactamase inhibitor intended for use in combination with cefepime or aztreonam for infections caused by Gram-negative bacteria resistant to carbapenems. Based on the results of two Phase III global studies—the Integral-1 study (enrolling patients with complicated urinary tract infections and acute uncomplicated pyelonephritis; jRCT2031230075) and the Integral-2 study (enrolling patients with infections caused by carbapenem-resistant Enterobacterales [CRE]; jRCT2031230076)—Meiji Seika Pharma submitted a New Drug Application (NDA) in Japan in December 2025.

Meiji Seika Pharma is committed to contributing to the fight against antimicrobial resistance (AMR), a global issue known as the silent pandemic.

About Nacubactam (Development Code: OP0595):
Nacubactam is a novel β-lactamase inhibitor developed by Meiji Seika Pharma. When used in combination with approved β-lactam antibiotics, it is expected to be effective against CRE. This mechanism restores the antimicrobial activity of β-lactam antibiotics against CRE. Additionally, OP0595 inhibits penicillin-binding protein 2 (PBP2), an enzyme involved in the biosynthesis of peptidoglycan, a key component of bacterial cell walls. This additional mechanism enhances the antimicrobial activities of β-lactam antibiotics against CRE. This dual mechanism differentiates it from existing β-lactamase inhibitors.

References:
Venkatesan P. ESCMID Global Congress 2026. The Lancet Microbe. 2026:101476.

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