Relypsa Announces Results of Sub-Group Analyses from Phase 3 OPAL-HK Trial of Veltassa (patiromer) Presented at ASN Kidney Week 2015

  • Veltassa significantly reduced and maintained control of blood potassium levels in OPAL-HK pre-specified sub-group analysis of patients age 65 and older with chronic kidney disease (CKD) and hyperkalemia
  • OPAL-HK post-hoc diuretic sub-group analysis showed Veltassa significantly reduced blood potassium levels in patients over four weeks, regardless of diuretic use  
  • As previously announced, OPAL-HK trial achieved primary endpoints and Veltassa was well tolerated

REDWOOD CITY, Calif., Nov. 06, 2015 (GLOBE NEWSWIRE) -- Relypsa, Inc. (NASDAQ:RLYP), a biopharmaceutical company, today announced results of a pre-specified sub-group analysis from the Phase 3 OPAL-HK trial of Veltassa™ (patiromer) for oral suspension. Data showed Veltassa significantly reduced and maintained control of blood potassium levels in hyperkalemic CKD patients age 65 and older who were also receiving renin angiotensin aldosterone system (RAAS) inhibitor therapy. Veltassa was recently approved by the U.S. Food and Drug Administration as the first new medicine for the treatment of hyperkalemia in more than 50 years.

A separate post-hoc analysis also from the OPAL-HK trial showed Veltassa’s efficacy in treating hyperkalemia was not diminished by concomitant use of diuretics. Veltassa was well tolerated in both sub-groups, with mild-to-moderate constipation as the most common adverse event.

“These data suggest Veltassa’s efficacy is similar for patients older than 65 years and for younger patients. This is important because older patients have a greater chance of developing elevated blood potassium levels due to common co-morbid conditions,” said presenter Matthew R. Weir, M.D., lead investigator of the OPAL-HK trial and professor and director, Division of Nephrology, University of Maryland School of Medicine. “We have also shown in a retrospective analysis that Veltassa’s efficacy remained consistent with concomitant diuretic use. Diuretics are frequently prescribed to people with CKD and heart failure to reduce fluid volume and blood pressure, or to control symptoms.” 

OPAL-HK Sub-Group Analysis of Patients Age 65 Years or Older (Abstract: TH-OR035)

Results of the OPAL-HK sub-group analysis of patients age 65 years or older were presented by Dr. Weir during an oral presentation on Thursday, November 5, 2015 at the American Society of Nephrology’s (ASN) Kidney Week 2015.

Of the 243 patients in the OPAL-HK trial, 131 (54 percent) were age 65 or older. In addition to CKD, patients in this sub-group had a high prevalence of co-morbidities such as hypertension (96.9 percent), type 2 diabetes (59.5 percent) and heart failure (51.9 percent). All patients (100 percent) were taking at least one RAAS inhibitor. The sub-group analysis showed:

  • Veltassa significantly reduced mean blood potassium levels from baseline to week four (p<0.001), and achieved normal blood potassium levels in 73 percent of patients age 65 and older at week four. These results were consistent with those seen with patients under age 65 (79 percent at four weeks).
  • Veltassa significantly reduced the percentage of patients age 65 and older with recurrent hyperkalemia compared with placebo over eight weeks (p<0.001).
  • One hundred percent of patients age 65 and older taking Veltassa were still receiving RAAS inhibitors after eight weeks, versus 30 percent of patients age 65 or older taking placebo.
  • Veltassa was well tolerated, and its safety profile was consistent with that observed in other clinical trials. The most common adverse event in patients age 65 or older was mild-to-moderate constipation (14.5 percent in the treatment phase and 6.9 percent in the withdrawal phase).

OPAL-HK Diuretic Sub-Group Analysis (Abstract: TH-PO658)

Separately, in an earlier poster session on Thursday, November 5, 2015, Dr. Weir also presented results from a post-hoc analysis of the sub-group of patients taking diuretics in OPAL-HK. Of the 243 CKD patients with hyperkalemia enrolled in OPAL-HK, 132 (54 percent) were taking one or two classes of diuretics at baseline.

Diuretics are frequently prescribed to CKD and heart failure patients. Though diuretics can also reduce elevated blood potassium levels, high doses may lead to side effects. This sub-group analysis compared the effects of Veltassa in patients taking different types of diuretics to patients who were not receiving diuretics in the treatment phase of OPAL-HK.

Veltassa significantly reduced blood potassium levels both in patients who were not receiving diuretic therapy and those taking any diuretic at week four (p<0.001), and significant reductions in mean blood potassium were seen as early as 48 hours after the first dose, regardless of diuretic use. The study authors concluded that Veltassa’s efficacy in treating hyperkalemia was not diminished by concomitant use of diuretics. Veltassa was also well tolerated among patients taking diuretics, with mild-to-moderate constipation as the most common adverse event (7.6 percent).


The main results of the pivotal Phase 3 OPAL-HK study of Veltassa were previously published in the New England Journal of Medicine.1 The trial achieved its primary endpoints and Veltassa was well tolerated.

In the OPAL-HK trial, 243 CKD patients with hyperkalemia (blood potassium levels ≥5.1 – <6.5 mEq/L) received Veltassa (8.4 g or 16.8 g as a divided dose) for four weeks (treatment phase). The primary endpoint of the treatment phase was the mean change in blood potassium levels from baseline to week four in patients who received at least one dose of Veltassa 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 blood potassium levels within the target range (3.8 – <5.1 mEq/L) after the initial four weeks of treatment were randomly assigned to continue Veltassa or switch to placebo for another eight weeks (randomized withdrawal phase). The primary endpoint of the randomized withdrawal phase was the difference between the Veltassa 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

Approximately 3 million people in the United States with stage 3 or 4 CKD and/or heart failure have hyperkalemia, or elevated blood potassium levels. Hyperkalemia can cause abnormal heart rhythms and even sudden death. There are often no warning signs, meaning a person can unknowingly experience spikes in potassium levels recurrently and be at risk for these cardiac events. Some medicines that are frequently prescribed to people with CKD and heart failure to help delay progression of their underlying disease can cause hyperkalemia as a side effect. These include RAAS inhibitors such as ARBs (angiotensin receptor blockers), AAs (aldosterone antagonists) and ACE (angiotensin-converting-enzyme) inhibitors.

About Veltassa

Veltassa is a potassium binder approved for the treatment of hyperkalemia. Veltassa should not be used as an emergency treatment for life-threatening hyperkalemia because of its delayed onset of action.

Made in powder form consisting of smooth, spherical beads, this new medicine is mixed with water (90 milliliters or 3 ounces) and taken once-a-day with food. Veltassa is not absorbed and acts within the gastrointestinal tract. It binds to potassium in exchange for calcium, primarily in the colon. The potassium is then excreted from the body through the normal excretion process.


The Prescribing Information for Veltassa includes a Boxed Warning that Veltassa binds to many other orally administered medications, which could decrease their absorption and reduce their effectiveness. Other oral medications should be administered at least 6 hours before or 6 hours after Veltassa. Doctors should choose Veltassa or the other oral medication if adequate dosing separation is not possible.


Veltassa is contraindicated in patients with a history of a hypersensitivity reaction to Veltassa or any of its components.

Worsening of Gastrointestinal Motility  

Use of Veltassa should be avoided in patients with severe constipation, bowel obstruction or impaction, including abnormal post-operative bowel motility disorders, because Veltassa may be ineffective and may worsen gastrointestinal conditions. Patients with a history of bowel obstruction or major gastrointestinal surgery, severe gastrointestinal disorders, or swallowing disorders were not included in clinical studies.


Veltassa binds to magnesium in the colon, which can lead to hypomagnesemia. In clinical studies, hypomagnesemia was reported as an adverse reaction in 5.3 percent of patients treated with Veltassa. Approximately 9 percent of patients in clinical trials developed hypomagnesemia with a serum magnesium value <1.4 mg/dL. Doctors should monitor serum magnesium and consider magnesium supplementation in patients who develop low serum magnesium levels.

Adverse Reactions

The most common adverse reactions (incidence ≥ 2 percent) were constipation, hypomagnesemia, diarrhea, nausea, abdominal discomfort and flatulence. Mild to moderate hypersensitivity reactions were reported in 0.3 percent of patients treated with Veltassa and included edema of the lips.

For additional Important Safety Information and Veltassa’s full Prescribing Information, please visit

About Relypsa, Inc.

Relypsa, Inc. is a biopharmaceutical company focused on the discovery, development and commercialization of polymeric medicines for patients with conditions that are often overlooked and undertreated and can be addressed in the gastrointestinal tract. The Company’s first medicine, Veltassa (patiromer) for oral suspension, was developed based on Relypsa’s rich legacy in polymer science. Veltassa is approved in the United States for the treatment of hyperkalemia. Veltassa 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 advantages of Veltassa for the management of hyperkalemia in older patients and patients with concomitant diuretic use. 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 and commercialization process, including regulatory requirements, Relypsa's substantial dependence on Veltassa, Relypsa's commercialization plans and efforts and other matters that could affect the availability or commercial potential of Veltassa. 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 September 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