AstraZeneca and FibroGen say they are preparing a US filing of roxadustat for anaemia in chronic kidney disease after reporting cardiovascular outcomes data from phase 3 trials.
The cardiovascular safety data found that roxadustat was less likely to be associated with major adverse cardiovascular events (MACE) than epoetin alfa, a standard therapy for anaemia in CKD, in patients who required dialysis.
The new drug was also non-inferior to placebo in patients with less severe CKD who were not on dialysis, said AZ and FibroGen in a press release. From a safety perspective that would seem to indicate a greater chance of roxadustat getting a clean label from the FDA, although there was some confusion about the results with shares in FibroGen dropping sharply in after-hours trading.
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.
If the FDA concurs with that interpretation, roxadustat could potentially avoid a warning on its label if it gets approved in the US, setting up a stronger challenge to the standard therapy in the market. Epoetin alfa is sold by Amgen as Epogen and Janssen as Procrit, but these brands were joined by Pfizer’s lower-cost biosimilar Retacrit last year.
FibroGen’s sell-off seemed to relate to what some observers considered was cautious language in the company’s recent 10-Q filing with the Securities & Exchange Commission (SEC) on the cardiovascular safety data.
That has however been attributed to differences between the EU and US regulators on defining non-inferiority in MACE, although there is still a lot of debate about how to interpret the top-line data on Twitter.
Roxadustat is already approved in China – where CKD is a particularly pressing medical problems – and is now on track for a filing in the US before the end of the year, according to AZ.
“These results add to the growing body of positive evidence to support roxadustat … following our announcement that the primary efficacy endpoints were met for the OLYMPUS and ROCKIES trials in December 2018,” said AZ’s head of biopharma R&D Mene Pangalos.
“There is a significant unmet medical need among patients living with chronic kidney disease, and we look forward to working with FibroGen to prepare for regulatory submissions of roxadustat.”
Analysts suggest the drug could bring in sales of $2bn or more at peak, with plenty of additional upside – perhaps as much as $4bn to $5bn, according to Leerink – if it has a clean enough safety profile to also get approval for non-dialysis CKD patients.