GSK chases FibroGen's lead as anemia drug daprodustat starts phase 3

GSK's oral drug could be an alternative to injectable erythropoiesis-stimulating agents.

The race to develop a more "natural" way to boost red blood cells in anemia patients has stepped up a gear, now that GlaxoSmithKline has started pivotal trials of its daprodustat candidate.

GSK says daprodustat is a hypoxia-inducible factor prolyl hydroxylase inhibitor (HIF-PHI), an emerging class of drugs that are being pitched as a more convenient oral alternative to injectable erythropoiesis-stimulating agents (ESAs) like Amgen's Epogen and Aranesp and Johnson & Johnson's Procrit.

Daprodustat (formerly GSK 1278863) and other HIF-PHIs work in a different way than ESAs, mimicking the effect of high altitudes on the body to spur red blood cell production. In addition to avoiding injections, they may also have safety advantages including a reduced tendency to raise blood pressure.

GSK is playing catch-up in the development of the class with FibroGen—whose roxadustat started phase 3 testing since 2014 and has been licensed to Astellas and AstraZeneca—as well as Akebia Pharma/Mitsubishi Tanabe which has vadadustat in late-stage testing a little bit behind roxadustat. 

"For many patients with chronic kidney disease, treating their anemia comes with risks associated with cardiovascular safety and injectable administration," said GSK's Julian Jenkins, who is heading up the development program for daprodustat.

The start of phase 3 trials will "explore whether daprodustat could address those risks and provide a potential alternative, oral treatment option," he added. If that proves to be the case the drug could be able to tap into a market estimated by Datamonitor to be worth around $5 billion a year.

GSK's phase 3 program will test the drug's ability to treat anemia caused by chronic kidney disease, including both dialysis and nondialysis patients. It will include two trials: ASCEND-D in dialyzed patients who will switch from an ESA to daprodustat and ASCEND-ND in nondialyzed patients who will either switch from or be naive to ESA therapy.

Datamonitor has predicted that roxadustat is likely to reach the market first and could become a $2 billion brand, particularly if FibroGen and its partners can expand the uses of the drug into additional indications like anemia caused by myelodysplastic syndrome (MDS). FibroGen said recently it is anticipating the first regulatory filings for its drug in 2018.