Keryx Biopharmaceuticals saw its stock jump as much as 27% after unveiling promising mid-stage data for its experimental kidney disease drug Zenerex.

The group reported top-line data from its Phase II study of Zerenex (ferric citrate coordination complex) in patients with chronic kidney disease (NDD-CKD) not on dialysis but with elevated serum phosphorus and iron deficiency anaemia. 

The trial met both co-primary endpoints, showing that the drug induced a statistically significant reduction in both serum phosphorus - a high concentration of which is linked with disease progression and death - and transferrin saturation (TSAT) after week 12 of treatment versus placebo.

Zerenex also hit secondary goals such as increasing ferritin and haemoglobin versus placebo, and appeared to be safe and well-tolerated, with discontinuation rates of 19% and 32% in the Zerenex and placebo groups, respectively, and none due to hypophosphataemia. 

The data, said Ron Bentsur, Keryx' chief executive, demonstrate that Zerenex "can potentially treat elevated phosphorus and also iron deficiency anaemia in CKD patients without the need for IV iron and ESAs [erythropoiesis stimulating agents]", which are associated with cardiovascular risk.

The company now plans to meet with the US Food and Drug Administration to determine a path forward towards obtaining a labeled indication for the treatment of iron deficiency anemia in NDD-CKD patients, it said.

Potential blockbuster?

Shareholders certainly seem excited over the drug's potential, which is unsurprising given that Bentsur has predicted that Zerenex sales could overshoot $1 billion with just a 7% share of the market for this subset of patients, reports Reuters.

"Simply put, the data presented demonstrate that Zerenex, an oral iron drug that increases iron stores and mitigates the need for IV iron and ESAs, has the potential to change the treatment paradigm for iron deficiency anaemia in CKD," said Steve Fishbane, Co-Chairman of the study, commenting on its potential.

"An oral drug producing these results suggests the potential for a more efficient and safer approach to anaemia management than currently offered by today's intravenous therapies."