A US FDA Advisory Committee’s overwhelming rejection of FibroGen/AstraZeneca’s oral anti-anemia agent is a big setback for the sponsor. But the committee’s reaction to novel strategies used to try to save the application has an important message for all drug developers about the limits of those approaches.

AstraZeneca and FibroGen hit another safety roadblock with roxadustat, while GSK is hoping it might catch up with its rivals in the US.

But advisory committee members see a potential opportunity for the oral anemia drug in small percentage of dialysis-dependent patients not responsive to erythropoiesis-stimulating agents; FibroGen’s revised dosing algorithm, aimed at slowing hemoglobin rate of increase and reducing risk of thrombosis, needs to be clinically tested before marketing approval, panelists said.

Risks of serious thrombotic events, seizures and infection make the benefits of the first-in-class oral drug for treating anemia related to chronic kidney disease ‘difficult to calculate’ despite demonstrated improvements in hemoglobin, FDA says in advisory committee briefing document.