Relypsa Enrolls Initial Patient in Pivotal Phase 3 Program for the Treatment of Hyperkalemia

Redwood City, CA, February 20, 2013 – Relypsa, Inc., a clinical-stage biopharmaceutical company, announced that he first patient has been enrolled in the company’s pivotal Phase 3 clinical study 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 study is being conducted in 2 parts with each part serving as a pivotal study under an agreed upon special protocol assessment (SPA) with the U.S. Food and Drug Administration (FDA), and will follow 240 patients for up to 12 weeks.

• 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. 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.

Top-line results are expected to be reported in the fourth quarter of 2013.

"Having observed the efficacy and safety data from the phase 2b study presented at ASN in 2012, I am confident this pivotal study will demonstrate the efficacy and safety of patiromer for the treatment of hyperkalemia in CKD patients receiving renin angiotensin and/or aldosterone blockade," said Professor Matthew Weir, Principal Investigator and Director of the Division of Nephrology at the University of Maryland School of Medicine. "Given the challenges of managing hyperkalemia in patients with kidney failure, solutions such as patiromer could offer physicians a new treatment option to control hyperkalemia facilitating better overall management of their CKD patients, for the first time in over 50 years."

"Commencing our Phase 3 pivotal program is a major step forward for patiromer and represents an important milestone toward our goal of making this drug available to all hyperkalemic patients," said Gerrit Klaerner, Ph.D., President of Relypsa. "We are very pleased at the progress of this program and thank the investigators involved for their support in advancing this important therapy that has the potential to significantly improve patient outcomes".

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,

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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