Oritavancin Useful for Managing Serious Infections in Cancer Patients

Oritavancin is a useful antimicrobial option to help clinicians manage methicillin-resistant Staphylococcus aureus (MRSA) infections and other serious Gram-positive cocci (GPC) infections in patients with cancer, including in those at the end-of-life, according to the findings of two recent studies.

“Infection represents an important cause of increased morbidity and mortality in patients with cancer and early introduction of appropriate antimicrobial therapy is essential for patient survival, write Michael A. Pfaller, MD, from the University of Iowa, Iowa City, and colleagues, in their recent article in the Journal of Antimicrobial Chemotherapy.

GPC are the most common pathogens isolated from cancer patients, they explain, and these especially include organisms such as MRSA and vancomycin-resistant enterococci (VRE). Approved for use in the United States in 2014, oritavancin belongs to the lipoglycopeptide class of antimicrobial agents and is effective against these and other GPC. The antimicrobial agent has a long half-life, and acts by interfering with the production of the bacterial cell wall and by disrupting the structural integrity of the bacterial cell membrane,

In their study, the researchers tested the antimicrobial activity of oritavancin against 1,357 isolates of GPC causing infections in cancer patients from 51 European and US medical centers. They also compared its activity with that of several other GPC agents, including daptomycin, vancomycin, teicoplanin, trimethoprim-sulfamethoxazole, and linezolid.

According to Dr. Pfaller and colleagues, more than half (54.6%) of the isolates were from bloodstream infections.

They found that 99.9% of S. aureus and vancomycin-susceptible Enterococcus faecalis, and 98.9% of streptococci, were susceptible to oritavancin at £0.12 mg/L and £0.25 mg/L, respectively. The activity of oritavancin against these isolates was comparable to that of daptomycin, linezolid, teicoplanin, and vancomycin, in particular. And, oritavancin, daptomycin, and linezolid showed activity against VRE, including VanA-type VRE.

Dr. Pfaller and colleagues stress that these findings provide useful information about the antimicrobial resistance profile of GPC isolates that affect patients with cancer and highlight the potential for oritavancin to treat serious GPC infections, including those associated with MRSA and VRE.

In an interview with Contagion^®, Rupak Datta, MD, PhD, Yale School of Medicine, New Haven, Connecticut, added that such infections are also common among advanced cancer patients near the end of life. “The management of these infections may be complicated,” he said, “particularly when intravenous antimicrobials are indicated and there are stated goals of comfort. Intravenous antimicrobials may cause discomfort and delay transition to hospice care.”

However, being a long-acting lipoglycopeptide with broad Gram-positive coverage, oritavancin avoids both this discomfort and the risks associated with intravenous dosing, including phlebitis and skin and soft tissue infections. Its long half-life also makes it useful for treating infections in end-of-life patients who may be entering the care of hospice agencies that preclude intravenous antimicrobial therapies.

Indeed, their article published recently in Open Forum Infectious Diseases, Dr. Datta, and colleagues report three cases of patients with terminal cancer who had MRSA, Streptococcus gallolyticus, and Granulicatella adiacens bacteremia who received the long-acting lipoglycopeptide oritavancin to facilitate discharge to hospice.

These patients included: a 64-year-old man with metastatic hepatocellular carcinoma and poorly controlled diabetes; a 72-year-old woman with recurrent non—small cell lung cancer; and a 69-year-old woman with metastatic stage IV non–small cell lung cancer.

“We show that long-acting lipoglycopeptides may have benefit in select patients with invasive infection in whom antimicrobial therapy is desired per patient and family discussions,” Dr. Datta concluded to Contagion^®.

Dr. Parry graduated from the University of Liverpool, England in 1997 and is a board-certified veterinary pathologist. After 13 years working in academia, she founded Midwest Veterinary Pathology, LLC where she now works as a private consultant. She is passionate about veterinary education and serves on the Indiana Veterinary Medical Association’s Continuing Education Committee. She regularly writes continuing education articles for veterinary organizations and journals and has also served on the American College of Veterinary Pathologists’ Examination Committee and Education Committee.