PHILADELPHIA – A 3-month course of levofloxacin after kidney transplant didn’t prevent BK virus from colonizing the urine, setting the stage for viremia in these immunosuppressed patients.
However, the antibiotic was associated with a significant 75% increase in the risk of developing a quinolone-resistant infection, compared with placebo, Dr. Greg A. Knoll and his colleagues reported in the Nov. 15 issue of JAMA (2014 [doi:10.1001/jama.2014.14721]).In a randomized trial of 154 kidney transplant patients, BK virus developed in 29% of those taking levofloxacin and in 33% of those taking placebo, a nonsignificant difference, coauthor Greg Knoll said at a late-breaking poster session during Kidney Week 2014, where the study was simultaneously presented.Levofloxacin, a quinolone antibiotic, has been shown to have some antiviral properties, especially against polyomaviruses – including BK virus, said Dr. Knoll of the University of Ottawa and the Ottawa Hospital.
Almost everyone harbors latent BK virus, Dr. Knoll said in an interview. It sometimes causes mild cold symptoms when first contracted, but often there’s no indication of illness at all. “If you’re otherwise healthy, it goes dormant and stays that way,” he noted.
But it can cause serious problems in immunocompromised patients, especially those with a kidney transplant. “BK virus tends to live in the bladder and urinary tract,” Dr. Knoll said, “So, when it reactivates, that’s the site where it does its damage.”
The virus will first appear in the urine, and then follow a logical progression through the ureters and into the kidney. If it remains unchecked, it causes very severe kidney inflammation. That inflammation “looks a lot like rejection,” Dr. Knoll said. “In fact, for years, we were very confused about this and ended up giving patients with BK viremia more immunosuppressants – when we actually should have been giving them less.”
It’s been tough to find the right balance of treatment to combat BK infections and immunosuppressants to maintain the allograft, he said.
Some retrospective studies suggested that quinolone antibiotics – including levofloxacin – could help fight cytomegalovirus infections and viral pneumonia, and decrease inflammatory markers in the urine of kidney transplant patients. “This was the little bit of evidence we needed to launch this study,” Dr. Knoll said.
The study investigators examined the time to first occurrence of BK viruria within the first year of transplant. Secondary outcomes included BK viremia, peak viral load, rejection, and patient and allograft survival.
Patients’ mean age was 48 years. They had undergone kidney transplant for a variety of reasons, including glomerulonephritis, polycystic kidney disease, diabetes, and hypertension. Comorbidities were common and included diabetes, history of cancer, cardiovascular disease, and hepatitis C and B infections. Most had received a living donor transplant (60%); the rest had kidneys from deceased donors.
Treatment began soon after transplantation. Patients were randomized to a target dose of 500 mg/day levofloxacin for 3 months. The mean length of follow-up was 46 weeks.
The primary outcome of BK viruria occurred in 46 patients – 29% of those in the levofloxacin group and 33.3% of those in the placebo group. That translated to a nonsignificant increased viruria risk of about 4%.
The time to viruria was not significantly different between the groups, with nearly 25% of each group developing it by 25 weeks. Nor was there a between-group difference in the occurrence of sustained viruria.
The secondary endpoint of BK viremia occurred in 7.9% of the levofloxacin group and 11.5% of the placebo group, also a nonsignificant finding. Infections were similar in both group, occurring in 59% of those taking levofloxacin and 45% of those taking placebo. The types of infections were similar: urinary tract/pyelonephritis (37% active vs. 38% placebo); cytomegalovirus (35% vs. 33%); pneumonia (3.5% vs. 1.7%); cellulitis (2.7% vs. 0.8%); and line infections and bacteremias, which were less than 1% in each group. No patient developed a Clostridium difficile infection.
However, patients taking levofloxacin developed significantly more quinolone-resistant infections (46.7% vs. 32.6%). Among isolates that are usually sensitive to quinolones, those patients taking the study drug were 75% more likely than were placebo patients to have a resistant strain (58.3% vs. 33.3%).
Because quinolones are an important part of infection prophylaxis in kidney transplant patients, “This would have significant implications for the management of common infections after transplantation,” Dr. Knoll said. “Our results don’t support the use of levofloxacin for preventing infections in patients with kidney transplants.”
The researchers were disappointed in the outcomes, “but there were people doing this already, and now we have the evidence to tell them to stop,” Dr. Knoll explained. “Of course, we are back to square one, with no proven treatment.”