European Journal of Heart Failure Publishes Pre-Specified Sub-Group Analysis of Heart Failure Patients With Hyperkalemia From Phase 3 Trial of Patiromer FOS

  • Pre-specified sub-group analysis from OPAL-HK trial of hyperkalemic chronic kidney disease (CKD) patients with heart failure receiving renin angiotensin aldosterone system (RAAS) inhibitor therapy
  • In heart failure sub-group, Patiromer FOS significantly reduced blood potassium to normal levels and prevented recurrent hyperkalemia compared with placebo
  • As previously announced, OPAL-HK trial achieved primary endpoints and Patiromer FOS was well tolerated

REDWOOD CITY, Calif., Oct. 13, 2015 (GLOBE NEWSWIRE) -- Relypsa Inc. (NASDAQ:RLYP), a biopharmaceutical company, today announced that results of a pre-specified sub-group analysis from the Phase 3 OPAL-HK clinical trial of Patiromer for Oral Suspension (Patiromer FOS) were published today in the European Journal of Heart Failure. These data were previously presented in a late breaking clinical trial session at the Heart Failure Society of America Annual Meeting in September 2014.

“Patiromer FOS helped people with heart failure and hyperkalemia reduce their blood potassium levels to the normal range and reduced the recurrence of dangerously elevated potassium,” said Bert Pitt, M.D., lead author of the European Journal of Heart Failure paper and professor of medicine emeritus in the Department of Internal Medicine at the University of Michigan Medical School. “The findings also showed that heart failure patients could stay on their RAAS medicines while managing their potassium levels with Patiromer FOS. This analysis further supports that, if approved, Patiromer FOS could transform the way hyperkalemia is managed in heart failure patients.”

The sub-group analysis in hyperkalemic CKD patients with heart failure showed that Patiromer FOS significantly reduced mean blood potassium levels from baseline to week four (p<0.001), and 76 percent of heart failure patients had normal blood potassium levels at four weeks. Patiromer FOS significantly reduced the percentage of heart failure patients with recurrent hyperkalemia compared with placebo over eight weeks (p<0.001). Additionally, 100 percent of heart failure patients on Patiromer FOS were still receiving RAAS inhibitors after eight weeks, versus 55 percent of heart failure patients on placebo.

Safety and tolerability of Patiromer FOS was similar between patients with and without heart failure and consistent with that observed in other clinical trials of Patiromer FOS. In the sub-group of heart failure patients, Patiromer FOS was well tolerated and the most common adverse event in these patients was mild-to-moderate constipation (11 percent).

The European Journal of Heart Failure publication of the sub-group analysis is available at The main results of the OPAL-HK study were previously published in the New England Journal of Medicine.1 The trial achieved its primary endpoints and Patiromer FOS was well tolerated.

OPAL-HK Study Design
In the OPAL-HK trial, 243 CKD patients with hyperkalemia (blood potassium levels ≥5.1–<6.5 mEq/L) received Patiromer FOS (4.2 g or 8.4 g twice daily initially) for four weeks (initial treatment phase). Of the 243 patients in the trial, 102 (42 percent) also had heart failure. Of these, 91 heart failure patients (89 percent) completed the initial treatment phase. The primary endpoint of the initial treatment phase was the mean change in blood potassium levels from baseline to week four in patients who received at least one dose of patiromer and had at least one potassium measurement after day three.

Patients who entered the trial with moderate-to-severe hyperkalemia (blood potassium levels 5.5–<6.5 mEq/L) and achieved normokalemia (blood potassium levels within the target range of 3.8–<5.1 mEq/L) after the initial four weeks of treatment were randomly assigned to continue Patiromer FOS or switch to placebo for another eight weeks (randomized withdrawal phase). A total of 49 patients with heart failure (54 percent) were randomly assigned either to continue Patiromer FOS (27 patients) or switch to placebo (22 patients). The primary endpoint of the randomized withdrawal phase was the difference between the Patiromer FOS and placebo groups in the median change in blood potassium levels from baseline to week four of that phase or the earliest visit when blood potassium was outside of the target range.

About Hyperkalemia
Hyperkalemia is a serious condition defined as abnormally elevated levels of potassium in the blood. It is frequently prevalent in patients who suffer from CKD, hypertension, diabetes and/or heart failure. Hyperkalemia can lead to life-threatening heart arrhythmias and sudden death. Patients with CKD or heart failure are at particular risk for developing hyperkalemia, especially those treated with RAAS inhibitors such as ARBs (Angiotensin Receptor Blockers), AAs (Aldosterone Antagonists), and ACE (Angiotensin-Converting-Enzyme) inhibitors. Although RAAS inhibition has been shown to protect kidney and cardiac function, many patients who could benefit from RAAS inhibitors are untreated or undertreated due to these medicines having an undesirable side effect of increasing blood potassium.

About Patiromer FOS
Patiromer FOS is a potassium binder, taken orally with a small amount of water, being developed for the treatment of hyperkalemia. Patiromer FOS has been evaluated in CKD patients with hyperkalemia, including a two-part Phase 3 program, a 12-month Phase 2 trial and a 48-hour Phase 1 onset-of-action trial. In all of those trials, Patiromer FOS met its efficacy endpoints and was well tolerated.

About Relypsa, Inc.
Relypsa, Inc. is a biopharmaceutical company focused on the development and commercialization of non-absorbed polymeric drugs to treat disorders in the areas of renal, cardiovascular and metabolic diseases. The company's lead product candidate is Patiromer for Oral Suspension for the treatment of hyperkalemia, a potentially life-threatening condition defined as abnormally elevated levels of potassium in the blood. A New Drug Application for Patiromer for Oral Suspension for the treatment of hyperkalemia was accepted by the U.S. Food and Drug Administration and is currently under review. Patiromer for Oral Suspension has intellectual property protection until 2030 in the United States and 2029 in the European Union. More information is available at

Forward-Looking Statements
To the extent that statements contained in this press release are not descriptions of historical facts regarding Relypsa, they are forward-looking statements reflecting the current beliefs and expectations of management made pursuant to the safe harbor provisions of the Private Securities Litigation Reform Act of 1995, including statements regarding the potential for, and timing of, approval and commercialization of Patiromer for Oral Suspension, or Patiromer FOS, and the potential of Patiromer FOS to transform hyperkalemia management. Such forward-looking statements involve substantial risks and uncertainties that could cause our clinical development program, future results, performance or achievements to differ significantly from those expressed or implied by the forward-looking statements. Such risks and uncertainties include, among others, the uncertainties inherent in the clinical drug development process, including the regulatory approval process, the timing of Relypsa's regulatory filings, Relypsa's substantial dependence on Patiromer FOS, Relypsa's commercialization plans and efforts and other matters that could affect the availability or commercial potential of Patiromer FOS. Relypsa undertakes no obligation to update or revise any forward-looking statements. For a further description of the risks and uncertainties that could cause actual results to differ from those expressed in these forward-looking statements, as well as risks relating to the business of Relypsa in general, see Relypsa's current and future reports filed with the U.S. Securities and Exchange Commission, including its Annual Report on Form 10-K for the year ended December 31, 2014 and its Quarterly Report on Form 10-Q for the quarterly period ended June 30, 2015.


1 Weir MR, Bakris GL, Bushinsky DA, Mayo MR, Garza D, et al. Patiromer in Patients with Kidney Disease and Hyperkalemia Receiving RAAS Inhibitors. N Engl J Med. 2015; 372:211-221.

Charlotte Arnold
Vice President, Corporate Communications

Source:Relypsa, Inc.