Stewardship / Resistance Scan for Aug 03, 2018

FDA azithromycin warning
Polymyxins and kidney injury

FDA issues azithromycin warning for cancer patients receiving stem cells

The US Food and Drug Administration (FDA) today issued a warning about long-term azithromycin use in cancer patients who've undergone a donor stem cell transplant.

The warning is based on the results of a clinical trial that found an increased rate of relapse in cancers affecting the blood and lymph nodes—and an increased death rate—among stem-cell transplant patients who were being treated with azithromycin to prevent bronchiolitis obliterans, a serious lung condition caused by inflammation and scarring in the airways of the lungs.

The researchers observed cancer relapse in 77 patients (32.9%) with azithromycin treatment compared with 48 patients (20.8%) taking placebo, and a total of 95 patients died in the azithromycin group compared with 66 patients in the placebo group. The investigators concluded that the risks of long-term azithromycin exposure after donor stem cell transplantation may exceed the benefits.

Although the trial could not determine why rates of cancer relapse and death were higher with azithromycin (which is not approved for preventing the condition), the FDA says healthcare providers should not prescribe long-term azithromycin to prevent bronchiolitis obliterans in patients with cancers of the blood or lymph nodes who've had a donor stem cell transplant. The agency says it's reviewing additional data and will communicate its conclusions and recommendations when the review is complete.

Pfizer, the manufacturer of Zithromax, is providing a letter on this safety issue to providers who care for patients undergoing stem cell transplants.
Aug 3 FDA safety announcement


Study highlights clinical, financial costs of kidney injury with polymyxin

A study today in Open Forum Infectious Diseases details the impacts of acute kidney injury in patients treated with polymyxin antibiotics.

The retrospective database analysis looked at adults who received intravenous (IV) treatment with one of two polymyxin antibiotics—sodium colistimethate (CMS) or polymyxin B (PMB)—for more than 3 consecutive days. The use of polymyxins has been on the rise as gram-negative organisms have grown increasingly resistant to other antibiotics, but there are concerns about drug-induced nephrotoxicity, specifically acute kidney injury (AKI). The researchers were seeking to assess the mortality risk, inpatient length of stay, and total hospitalization costs associated with AKI among patients who receive the drugs.

A total of 4,886 patients were included: 4,103 who received CMS and 783 who received PMB. In the multivariable analysis, the presence of AKI was associated with higher in-hospital mortality in the CMS group (adjusted odds ratio [aOR], 2.3) and the PMB cohort (aOR, 2.7) than those who didn't develop AKI, and with longer hospital stays (9.7 days and 11.6 days in the CMS and PMB cohorts, respectively). Mean total hospitalization costs were also higher for patients with AKI—$47,820 higher in the CMS cohort and $35,244 higher in the PMB cohort.

"Our findings suggest that the clinical and economic burden of AKI among polymyxin recipients is substantial and polymyxin therapy should be used judiciously," the authors conclude.

The study was sponsored by Allergan plc.
Aug 3 Open Forum Infect Dis abstract

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