FDA questions safety profile of AZ, FibroGen’s anaemia drug roxadustat

Ahead of an upcoming advisory committee meeting for AstraZeneca (AZ) and FibroGen’s anaemia drug candidate roxadustat, the FDA has questions about the drug’s safety profile. 

AZ and FibroGen are aiming for approval of roxadustat for the treatment of anaemia caused by chronic kidney disease (CKD).

In briefing documents published ahead of a meeting of the Cardiovacular and Renal Drugs Advisory Committee meeting on 15 July, the FDA said that “roxadustat’s efficacy is not in question”.

However, the document added that “the principal issues before the committee are the drug’s safety, and safety with respect to the specific CKD populations”.

The briefing documents included details from a pooled safety analysis of six phase 3 clinical trials in both non-dialysis (NDD) and dialysis-dependent patients.

According to this analysis, roxadustat was comparable to epoetin alfa, a standard therapy for anaemia in CKD, on the composite measure of major adverse cardiovascular events (MACE).

However, the FDA raised concerns over serious thrombotic events and seizures with roxadustat treatment, which were detected against a placebo background in the NDD patient population and evident against epoetin alfa, “which is itself known to pose these risks”.

“Other signals of concern include serious adverse events of hypoglycaemia, gastroenteritis, and pancreatitis.”

AZ and FibroGen have previously made a case for roxadustat’s safety profile, highlighting that the drug could avoid the serious cardiovascular risks associated with epoetin alfa.

Epoetin alfa has a warning on the label that it can sometimes cause increased blood pressure, especially in patients with long-term kidney disease, which could increase the risk of cardiovascular events.

The risk is thought to be most acute with epoetin alfa when treatment is started, typically in patients in newly-initiated (incident) dialysis.

Looking at this group in particular, patients on roxadustat did better than those on epoetin alfa on so-called MACE+, which includes all-cause mortality, stroke and myocardial infarction (MACE) as well as heart failure and/or unstable angina requiring hospitalisation.

Roxadustat is already approved in China  – where CKD is a particularly pressing medical problems – under the brand name Evrenzo.