The Food and Drug Administration (FDA) has issued a Complete Response Letter (CRL) to FibroGen regarding its New Drug Application (NDA) for roxadustat for the treatment of anemia of chronic kidney disease (CKD) in both non-dialysis dependent and dialysis-dependent patients.

Roxadustat is an investigational oral hypoxia-inducible factor prolyl hydroxylase inhibitor that promotes erythropoiesis by increasing endogenous erythropoietin production. It also improves iron regulation and eases the negative impact of inflammation on hemoglobin synthesis and red blood cell production by downregulating hepcidin. The NDA included data from a global phase 3 program that evaluated the effects of roxadustat in over 8000 patients.

In July 2021, the FDA’s Cardiovascular and Renal Drugs Advisory Committee voted against the approval of roxadustat for this indication. The panel raised several questions about the roxadustat development program, particularly regarding the safety analyses. Concerns related to the potential for thromboembolic events and major adverse cardiovascular events were discussed during the meeting.

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In the CRL, the FDA stated that the application could not be approved in its present form and had requested an additional clinical study be conducted in both non-dialysis dependent and dialysis-dependent patients. 

“We are deeply disappointed with this result, and this is an unfortunate day for patients suffering from anemia of CKD in the United States,” said Enrique Conterno, CEO, FibroGen. “Roxadustat is changing the lives of patients around the world, and we and our partner AstraZeneca will discuss next steps in the US.”


  1. FibroGen receives Complete Response Letter from the FDA for roxadustat for anemia of chronic kidney disease. News release. FibroGen, Inc. Accessed August 11, 2021.
  2. Update on US regulatory review of roxadustat in anaemia of chronic kidney disease. News release. AstraZeneca. Accessed August 11, 2021.

This article originally appeared on MPR