According to preliminary results from a new study, the intake of anti-anemia drugs may be associated with an increased risk of death, federal officials cautioned last week.

On Friday, the Food and Drug Administration announced it was reviewing a higher rate of deaths among people treated with Eprex, an anemia drug produced by Johnson & Johnson, a global pharmaceutical, medical devices and consumer packaged goods manufacturer.

The German study was conducted to determine if brain function in stroke patients could be enhanced by taking Eprex. 522 people, predominantly anemic, participated in the trial. For a period of three days, they were given either reasonably high doses of the drug or a placebo, regulators said in a statement. The agency has only cleared Eprex to increase red blood cell (RBC) levels in people with anemia, a medical condition described as a deficiency of hemoglobin.

The results showed that 16% of patients who received the medication had passed away only three months after the start of the trial, compared to just 9% who took a placebo.

The FDA said the doses used in the study were considerably higher than the ones that appear on Eprex’s current labeling. Additional data on the trial is expected by federal health officials in the next couple of weeks. Also, after reviewing the drug, the agency will make recommendations to patients and physicians.

On the topic of the study, Dr. Samuel M. Silver, a spokesman for the American Society of Hematology, said the results are “interesting, because people were looking at potential neuroprotective effects of erythropoiesis-stimulating agents.”