MicuRx Pharmaceuticals Announces Positive Results from Phase 3 Clinical Trial of Contezolid for Complicated Skin and Soft Tissue Infections in China
Shanghai, China and Foster City, California, USA – September 19, 2019 – Micurx Pharmaceuticals today announced positive results from a pivotal Phase III clinical trial conducted in China evaluating contezolid (also known as MRX-I), its first novel antibacterial agent, for the treatment of complicated skin and soft tissue infections (cSSTI). Contezolid demonstrated non-inferiority to linezolid in terms of clinical cure rate at the primary endpoint, the Test-of-Cure (TOC) visit (7–14 days after the last dose), and exhibited a lower incidence of drug-related hematological adverse events.
“We are very pleased with the outstanding results of this Phase III clinical trial, which demonstrate that contezolid is an effective and safer antibacterial agent,” said Dr. Zhengyu Yuan, President and CEO of Micurx Pharmaceuticals. “We plan to submit a New Drug Application to the National Medical Products Administration (NMPA) in the fourth quarter of 2019,” Dr. Yuan added.
This double-blind trial was conducted at 50 clinical centers in China. Patients enrolled with complicated skin and soft tissue infections (cSSTI) were randomized to receive either oral contezolid 800 mg or linezolid 600 mg, twice daily for 7 to 14 days. Among the 719 enrolled patients, 589 were clinically evaluable (CE) at the Test-of-Cure (TOC) visit. In the CE population, the clinical cure rate of contezolid at the TOC visit (93.0%) was comparable to that of linezolid (93.4%), with a between-group difference of -0.4% and a 95% confidence interval (CI) of (-4.4%, 3.7%), meeting the non-inferiority margin of -10%. Furthermore, for all secondary efficacy endpoints, including the clinical cure rate at the End-of-Treatment (EOT) visit, the microbiological eradication rate at the TOC visit, and the composite response rate at the TOC visit, the lower bounds of the 95% CIs for the between-group differences were all greater than the -10% threshold, further demonstrating the comparable efficacy of contezolid and linezolid.
The overall incidence of treatment-emergent adverse events (TEAEs) was comparable between the contezolid and linezolid groups. The incidence of TEAEs deemed by investigators to be related to the study drug was also similar (23.4% for contezolid vs. 26.8% for linezolid), with most being mild or moderate in severity. However, regarding hematological examinations, the incidence of study drug-related TEAEs was lower in the contezolid group than in the linezolid group: decreased white blood cell count (0.28% for contezolid vs. 3.42% for linezolid; p=0.002); decreased neutrophil count (0.28% for contezolid vs. 1.71% for linezolid; p=0.068); decreased reticulocyte count (0.28% for contezolid vs. 1.42% for linezolid; p=0.123); and decreased platelet count (0% for contezolid vs. 2.28% for linezolid; p=0.004). Among the 405 patients who received treatment for more than 10 days, the proportion of patients with a >30% decrease in platelet count from baseline at the end-of-treatment (EOT) visit was 25.4% in the linezolid group, compared to only 2.5% in the contezolid group.
“Oxazolidinone antibiotics demonstrate excellent efficacy against infections caused by multidrug-resistant Gram-positive bacteria, but their clinical use is limited by the side effect of bone marrow suppression,” commented Professor Zhang Yingyuan, former Director of the Institute of Antibiotics at Fudan University and principal investigator of this clinical trial. “However, the results of this Phase III clinical study show that contezolid exhibits the efficacy characteristic of oxazolidinone antibiotics without bone marrow suppression-related toxicity,” Professor Zhang added.
Contezolid is an oral oxazolidinone antibacterial agent designed to treat infections caused by drug-resistant bacteria, such as methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococci (VRE), offering physicians and patients a safer and better-tolerated therapeutic option compared with existing oxazolidinones. The development of contezolid in China has received support from the “Major New Drug Creation” special program, and it has been granted Qualified Infectious Disease Product (QIDP) designation and Fast Track designation by the U.S. Food and Drug Administration (FDA). Dr. Yuan stated, “We sincerely thank all the patients and investigators who participated in this study, and I look forward to presenting more results from this pivotal Phase III clinical trial at the China Medicine Innovation and Investment Conference to be held in Suzhou on September 21, 2019.”
About Micurx Pharmaceuticals, Inc.
Micurx (http://www.micurxchina.com) is a clinical-stage biotechnology company focused on the discovery, development, and commercialization of antibacterial agents for the treatment of infections caused by multidrug-resistant (MDR) “superbugs.” Since its establishment in 2007, we have built a research and development pipeline that includes contezolid (MRX-I), contezolid acefosamil (MRX-4), MRX-8 (a novel polymyxin-class agent targeting MDR Gram-negative bacteria), and MRX-12 (a novel agent targeting MDR Gram-negative bacteria). Our mission is to combat pathogens listed on the World Health Organization’s (WHO) list of priority “superbugs.” Our lead product, contezolid (MRX-I), is a next-generation oxazolidinone antibiotic for the treatment of Staphylococcus aureus (including methicillin-resistant S. aureus, or MRSA) infections, designed through structural optimization to reduce the risk of hematological adverse effects and monoamine oxidase inhibition associated with this class of antibiotics. In 2015, Micurx successfully completed two independent Phase II studies of MRX-I in the United States and China, respectively, and completed a Phase III study for complicated skin and soft tissue infections (cSSTI) in China in 2019. Contezolid acefosamil (MRX-4) is a prodrug of contezolid, with both oral and injectable formulations planned for global development against infections caused by MDR Gram-positive bacteria. Both contezolid and contezolid acefosamil have been granted Qualified Infectious Disease Product (QIDP) designation and Fast Track designation by the U.S. Food and Drug Administration (FDA). The company operates R&D laboratories in the San Francisco Bay Area, California, USA, and in Shanghai, China. Micurx has raised a total of $107 million from leading venture capital firms, including Morningside Ventures, BVCF, GP Healthcare Capital, GP TMT Capital, 3E Bioventures Capital, and Delian Capital. For more information, please visit:
Contact Person
Li Zhile (Jerry)
Senior Vice President and Chief Financial Officer
Micurx Pharmaceuticals, Inc.
Phone: +852 6185 7868 (HK)
zli@micurx.com