New Phase III patiromer data boost Relypsa's IPO prospects
This article was originally published in Scrip
Relypsa upped its chances for a successful launch into the US stock market on 10 October when president and CEO John Orwin said the company plans to file for US FDA approval of the hyperkalemia drug candidate patiromer (RLY5016) based on statistically significant results from Part B of a Phase III clinical trial. Relypsa, which has the only therapy in development to treat high potassium levels in the blood, believes that its data support chronic dosing.
The News in a Nutshell
Redwood City, California-based Relypsa filed for a $126.5m IPO less than three weeks after the company reported a statistically significant 1.01mEq/L reduction in serum potassium from baseline to week four of its Phase III trial (p<0.001) for="" adult="" patients="" with="" hyperkalemia="" and="" chronic="" kidney="" disease="" (ckd)="" who="" were="" also="" taking="" a="" renin="" angiotensin="" aldosterone="" system="" (raas)="">
All 243 patients enrolled in the study were treated with patiromer during the first four weeks and patients whose serum potassium levels were controlled by the drug – 76% of Part A participants – were randomized to treatment with patiromer or placebo in Part B.
Elevated potassium levels in the blood can lead to fatal arrhythmia. People with renal impairment, hypertension, diabetes and heart failure have a higher risk for hyperkalemia. The condition is a common side effect of RAAS inhibitors prescribed for CKD and heart failure.
Given the already compromised health of patients who may take patiromer, if approved, Relypsa's performance in an IPO could be helped or harmed by forthcoming data from a longer-term mid-stage study.
Primary Endpoint details
The difference between the placebo and patiromer groups in terms of median change in serum potassium levels from Part B baseline to week 8 was 0.72mEq/L (p<0.001).>
Secondary Endpoint details
Part B of the clinical trial also evaluated the difference between the patiromer and placebo groups in terms of the proportion of patients who developed recurrent hyperkalemia. Serum potassium levels at or above 5.1mEq/L were measured in 91% of people in the placebo group and in 43% of patiromer-treated patients. Serum potassium at or above 5.1mEq/L was observed in 60% of placebo patients and 15% of people in the patiromer group.
Side-effect details
Relypsa previously disclosed two serious adverse events during Part A that were determined to be unrelated to patiromer. The company said in September that it will release more details at a future medical meeting.
Market size
Relypsa estimates that 20% to 40% of stage 3 and 4 CKD patients and heart failure patients have moderate-to-severe hyperkalemia, representing about 2.4m US patients who are being treated by nephrologists or cardiologists. The company believes that many millions more patients are not treated with RAAS inhibitors or get suboptimal doses of the drugs due to hyperkalemia concerns.
Next steps
Data from a 52-week Phase IIb clinical trial that enrolled 306 patients with CKD who were also treated with RAAS inhibitors will be revealed in the next few weeks. The Phase IIb trial has the potential to boost Relypsa's IPO prospects considerably if the longer-term study shows that the drug, which is dosed in an oral suspension, is safe and effective.
Relypsa intends to fund manufacturing and commercial preparations and pay expenses during the regulatory filing and review processes with proceeds from its IPO. The company intends to commercialize patiromer on its own in the US.
Related stories
Relypsa pursues $126.5m IPO for patiromer, 1 October 2013
Significant Part A results for Relypsa's Phase III hyperkalemia drug, 11 September 2013