FibroGen plunges 43% after the company says there were errors in safety analyses data for its anemia drug candidate

• FibroGen tumbled 43% after issuing a clarification on late-stage safety analyses for its anemia drug candidate, roxadustat.
• The company said it identified "post-hoc changes to the stratification factors."
• FibroGen has a meeting in July with an FDA committee about its new drug application for roxadustat.

FibroGen shares plunged as much as 43% on Wednesday after the biopharmaceutical developer said there were errors in certain disclosures about safety analyses for its anemia drug candidate roxadustat.

In a late Tuesday statement about phase 3 testing data for roxadustat, FibroGen CEO Enrique Conterno said the company "became aware that the primary cardiovascular safety analyses included post-hoc changes to the stratification factors."

Conterno said the company became aware of the changes to the stratification factors as members of senior management prepared for a meeting with the Food and Drug Administration's advisory committee about roxadustat.

"We promptly decided to clarify this issue with the FDA and communicate with the scientific and investment communities," he said.

FibroGen said it now cannot conclude that roxadustat is superior to reducing risks of cardiovascular events compared with epoetin-alfa, an already approved drug that can aid the body in producing red blood cells. Roxadustat is aimed at orally treating anemia in chronic kidney disease patients who are dependent or non-dependent on dialysis.

"It is important to emphasize that this does not impact our conclusion regarding the comparability, with respect to cardiovascular safety, of roxadustat to epoetin-alfa in dialysis-dependent patients and to placebo in non-dialysis dependent patients," said Conterno. "We continue to have confidence in roxadustat's benefit risk profile."

The FDA's advisory committee is tentatively scheduled to review the roxadustat application on July 15.