REDWOOD CITY, CA, USA I May 13, 2013 I Relypsa, Inc., a clinical-stage biopharmaceutical company, today announced that the company has completed enrollment of its pivotal phase 3 program of patiromer for the treatment of hyperkalemia in patients with chronic kidney disease (CKD). The two part phase 3 clinical trial is being conducted under an agreed upon special protocol assessment (SPA) with the U.S. Food and Drug Administration as follows:

• Part A – the patiromer treatment phase, is a single-blind, single-arm trial in 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.

• Part B – 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. Part B is designed to demonstrate the need for chronic treatment with patiromer. The primary analysis is the between group difference in the change in serum potassium from baseline to week 4 of Part B.

The company currently expects to have top-line study results in the fall of 2013.

“Rapid enrollment of this pivotal program in only three months is another illustration that patiromer has the potential to fulfill a significant medical need and that nephrologists are embracing the concept of a novel, chronic treatment of hyperkalemia,” said Gerrit Klaerner, Ph.D., President of Relypsa. “Completing enrollment of our pivotal program is a significant milestone that allows Relypsa to ramp up preparations to seek NDA approval and for commercial launch.”

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 (Renin Angiotensin Aldosterone System) 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) for Oral Suspension 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 in patients with hyperkalemia.

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, www.fda.gov.

About Relypsa, Inc.

Relypsa, Inc. is a late clinical-stage biopharmaceutical 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 www.relypsa.com.

SOURCE: Relypsa