Novel drug candidate, MRX-I, an oral oxazolidinone showed positive top-line results from the first Phase 2 clinical study in China, according to biopharmaceutical company, MicuRx Pharmaceuticals, Inc. today.

Staphylococcus aureus Image/CDC
Staphylococcus aureus

“These clinical data demonstrate that MRX-I has the potential to be a safe and effective antibiotic for a broad range of infections, including those that are multidrug-resistant,” said Dr. Zhengyu Yuan, president and CEO of MicuRx Pharmaceuticals, lnc.

MRX-I is an oral oxazolidinone antibiotic designed to treat drug-resistant bacteria such as MRSA and VRE, while offering physicians and patients a safer and better tolerated therapeutic option than currently available oxazolidinone agents.

In the double-blind study conducted at 29 sites in China, patients with complicated skin and soft tissue infections received either 600 mg or 800 mg of MRX-I, or 600 mg of linezolid, twice daily for a period of up to 14 days. Of 199 patients with confirmed or suspected Gram-positive bacterial infection at the time of admission, 178 patients were clinically evaluable at the test-of-cure (TOC) visit.

For the clinically evaluable patients, the clinical cure rates at the TOC visit were comparable for the MRX-I 800 mg group (96.5 percent) and the linezolid group (95.5 percent). Both doses of MRX-I demonstrated a favorable safety and tolerability profile. No drug-related serious adverse events were noted in patients receiving either MRX-I or linezolid.

“The oxazolidinone class of antibiotics stands out from others with a remarkably low propensity for bacterial resistance,” commented Dr. Yingyuan Zhang, director of the Institute of Antibiotics at Fudan University and the principle investigator of this study. “However, these antibiotics typically come with the myelosuppression adverse event, which limits its use. Data from the Phase 2 study of MRX-I reported today combined with prior Phase 1 trial results indicate that this promising agent may offer the efficacy of the oxazolidinone class without bone marrow toxicity.”

Dr. Yuan further noted that, “Adding to our body of clinical knowledge, we have completed dosing in a second Phase 2 trial conducted in the United States, and results will be available in the fourth quarter of 2015. The full data set for MRX-I will inform the design of our planned Phase 3 clinical trials.”

This Phase 2 study was funded through MicuRx’s joint venture with Shanghai Zhangjiang Biomedical Industry Venture Capital, founded to advance the development of MRX-I for the Chinese market. Data from two Phase 1 studies in China and Australia have confirmed that MRX-I was safe and well tolerated in healthy volunteers at all dose regimens, including 28-day repeated dosing regimen alongside Zyvox® as comparator, with no evidence of myelosuppression that is typical for this class.