Relypsa Announces Agreement with FDA on Special Protocol Assessment for Patiromer Phase 3 Trial for the Treatment of Hyperkalemia

According to data reported at Kidney Week 2012, an ongoing Phase 2b study of patiromer met the interim analysis primary endpoint of mean reduction in serum potassium after four weeks of treatment

Redwood City, CA, January 2, 2013 – Relypsa, Inc., a clinical-stage biopharmaceutical company, announced today a Special Protocol Assessment (SPA) agreement with the U.S. Food and Drug Administration (FDA) for the design of the Company’s pivotal, Phase 3 trial evaluating the efficacy and safety of patiromer for the treatment of hyperkalemia (high serum potassium levels) in patients with chronic kidney disease (CKD). The Phase 3 trial will consist of two parts, each serving as a pivotal study for the purposes of the New Drug Application (NDA) submission:
• Part A of the trial, the patiromer treatment phase, is a single-blind, single-arm study designed to enroll approximately 240 patients with CKD and hyperkalemia. The primary endpoint of Part A is change in serum potassium from baseline to week 4 after treatment with patiromer.
• Subjects who respond to treatment in Part A will be eligible for Part B, the withdrawal phase. Qualifying subjects will be randomized either to continue on patiromer or to receive placebo for an additional 8 weeks. The primary endpoint of Part B is the change in serum potassium from baseline to week 4. Part B is designed to demonstrate the need for chronic treatment with patiromer.
Relypsa plans to begin patient enrollment in the Phase 3 trial during the first quarter of 2013. Top-line results are expected to be reported in the fourth quarter of 2013.
“The SPA agreement is a major milestone that provides us with a clearly defined development and regulatory pathway for patiromer in the treatment of hyperkalemia,” commented Gerrit Klaerner, Ph.D., President of Relypsa. “Currently, the standard of care to treat hyperkalemia in patients with CKD is to reduce or stop a patient’s RAAS (Renin Angiotensin Aldosterone System) inhibition therapy, even though therapies belonging to this class have been shown to delay progression to dialysis and to reduce cardiovascular events and overall mortality. If approved by the FDA, patiromer would be the first therapeutic on the market with data to support long term use for the treatment of chronic hyperkalemia.”
At the American Society of Nephrology’s Kidney Week 2012, the Company presented positive results from an interim analysis of its ongoing phase 2b clinical study enrolling a total of 306 patients. The trial, known as AMETHYST-DN, is an ongoing, one-year open-label study evaluating the safety and efficacy of patiromer in reducing hyperkalemia in patients with CKD who are being treated with RAAS inhibitors, including ARBs. During the study, patients are orally administered patiromer to control hyperkalemia while maintaining recommended levels of RAAS inhibitor therapy. In this interim analysis, the initial 8-week treatment phase of the AMETHYST-DN study met its primary endpoint of mean reduction in serum potassium at 4 weeks compared with baseline, and demonstrated a rapid reduction of serum potassium as early as 48 hours after the first dose. Reductions in serum potassium were maintained for the full initial 8-week treatment phase.
About Special Protocol Assessments
A Special Protocol Assessment is a written agreement between a sponsor and the FDA that the design and planned analysis of a clinical trial can adequately address objectives in support of a marketing application. Final determinations for marketing approval are made after a complete review of a marketing application and are based on the entire data in the application. For further information regarding the SPA process, please visit the FDA website,
About Patiromer and Hyperkalemia
Hyperkalemia is a condition frequently prevalent in patients that suffer from renal impairment, hypertension, diabetes and/or heart failure. It is characterized by elevated serum potassium levels, which can lead to cardiac arrhythmia and sudden death. Patients with chronic kidney disease are at particular risk for developing hyperkalemia, especially those treated with RAAS inhibitors such as ARBs (Angiotensin Receptor Blockers) and AAs (Aldosterone Antagonists). Although RAAS inhibition has been shown to protect kidney and cardiac function, as well as prolong life, many patients who could benefit from RAAS inhibitors are untreated or undertreated due to the undesirable side effect of increasing serum potassium.
Patiromer (RLY5016) is a high capacity non-absorbed oral potassium binder being developed for the management of elevated serum potassium levels. Relypsa has completed several clinical trials of patiromer that have demonstrated the preliminary efficacy, safety and tolerability of patiromer for the treatment of hyperkalemia.
About Relypsa, Inc.
Relypsa, Inc. is a late clinical-stage pharmaceutical company leading the discovery and development of novel non-absorbed polymeric drugs for important applications in cardiovascular and renal diseases. Relypsa’s lead product candidate is patiromer, a non-absorbed potassium binder for the treatment of hyperkalemia. Relypsa is pursuing the discovery of additional product candidates through use of its proprietary polymer platform. More information is available at
Relypsa, Inc.
Kristine Ball, SVP, Chief Financial Officer
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