Novel Mechanisms to Solve Significant Medical Challenges
For decades, the gut had been under-recognized as a viable site for new therapeutic points of intervention for treating disease. Using our discovery model, which recreates environments within certain areas of the gastrointestinal tract and kidney, Ardelyx® scientists have been able to elucidate new and previously unexploited ion transport mechanisms. Focusing on these mechanisms, we are creating targeted, small molecule drugs that are orally active but with limited systemic absorption, aiming to develop potent and efficacious therapies that minimize the side effects and drug-drug interactions frequently encountered with traditional, systemically absorbed medicines.
Our Pipeline
Based on our successes to date in translating scientific insights into targeted therapies, our strategy enables the expansion of our pipeline with promising, novel mechanism, first-in-class drug candidates that target specific pharmacologic pathways and have the potential to meet significant unmet medical needs.
RDX013 for Hyperkalemia
Our discovery platform has enabled the systematic study of the biological mechanisms of potassium secretion and has led us to the discovery of RDX013, an investigational, first-in-class potassium lowering compound for the treatment of hyperkalemia. Hyperkalemia is a common problem in patients with kidney and heart disease and can cause a significantly increased risk of death because of the potential for heart conductance issues. RDX013 pharmacologically targets potassium secretion through the lumen of the gut, thus lowering levels of serum potassium.
Unlike current treatments that bind potassium, our lead candidate RDX013 represents a novel mechanism, targeted therapy that could create a completely new treatment paradigm for patients with hyperkalemia if successfully approved.
RDX020 for Metabolic Acidosis
Our research efforts have identified a set of potent, selective and proprietary bicarbonate secretion inhibitors. The resulting RDX020 program has the potential to provide a novel approach to treating metabolic acidosis, by targeting the intestinal bicarbonate exchange mechanism. Metabolic acidosis is a highly prevalent comorbidity in CKD patients and is strongly correlated with disease progression and adverse outcomes. There are currently no approved treatments for chronic metabolic acidosis.
What is CKD?
Chronic kidney disease (CKD) is the progressive deterioration of kidney function that can occur over time. The kidneys’ main job is to filter excess water and waste out of blood via urine. To keep the body working properly, the kidneys balance salts and minerals—such as calcium, phosphorus, sodium, and potassium—that circulate in the blood. Kidneys also make hormones that help control blood pressure, make red blood cells, and keep bones strong.
If deterioration of the kidneys continues, the disease will likely cause significant cardiovascular morbidity, and can progress to kidney failure.
Current management of kidney failure includes hemodialysis and peritoneal dialysis as a means to filter toxins from the blood once the kidneys have failed. Without dialysis or transplant, kidney failure results in the accumulation of waste products that may ultimately cause death. Hemodialysis, the most common form of dialysis, generally requires a patient to visit a dialysis center at least three times per week for a minimum three-hour session, significantly impacting quality of life.
There are currently estimated to be more than 35 million people in the U.S. suffering from chronic kidney disease, more than 550,000 of whom are treated with dialysis.
What is Hyperphosphatemia?
Hyperphosphatemia, a nearly universal condition in the more than 550,000 patients in the U.S. with CKD on dialysis, is an electrolyte disorder in which there is an elevated level of phosphate in the blood.
While dialysis is the basis for homeostatic electrolyte management, dialysis regimens are unable to successfully remove excess phosphate in order to achieve a neutral phosphate balance. As a result, approximately 80% of patients with CKD on dialysis require phosphate-lowering therapy on top of restrictive, low phosphorus diets.
Management of hyperphosphatemia has been a long-time challenge. While the 2017 Kidney Disease Improving Global Outcomes (KDIGO) clinical practice guidelines recommend lowering elevated phosphate levels toward the normal range (2.5-4.5 mg/dL or 0.81-1.45mmol/L), due to the difficulties in managing phosphorus, most clinicians target phosphorus levels between 3.5-5.5 mg/dL (1.13-1.78 mmol/L), based on the 2003 Kidney Disease Outcomes Quality Initiative (KDOQI) clinical practice guidelines.
What is Hyperkalemia?
Hyperkalemia is a potentially life-threatening condition in which blood levels of potassium are elevated above normal. Potassium is a nutrient that is critical to the normal function of nerve and muscle cells, including those in the heart. Normal potassium blood levels are tightly balanced and maintained primarily by the kidneys. For people with chronic kidney disease (CKD), heart failure and diabetes, and particularly those also taking renin-angiotensin-aldosterone system (RAAS) inhibitors, there is a greater risk of developing hyperkalemia due to the kidneys' reduced ability to keep potassium in balance.
Several published guidelines have suggested that physicians should reduce, and possibly discontinue, RAAS inhibition when hyperkalemia develops in order to manage the risk of elevated potassium in CKD and heart failure patients. The alternative medications used to control hypertension, including diuretics and calcium channel blockers, are less effective than RAAS inhibitors, particularly in patients with failing kidneys and severe hypertension.
What is Metabolic Acidosis?
Metabolic Acidosis is a condition which occurs in CKD patients who are unable to maintain normal acid-base homeostasis. As kidney function declines, the capacity of the kidneys to excrete the daily acid load is impaired, resulting in acid retention.
The condition of metabolic acidosis is associated with CKD disease progression, bone demineralization, skeletal muscle catabolism, and mortality.
There are currently no approved treatments for metabolic acidosis, and nephrologists attempt to control the condition by giving patients large quantities of oral alkali salts that can lead to increased sodium load and fluid retention.

What is IBSRELA®?
IBSRELA® (tenapanor) 50 mg tablets is a prescription medicine used in adults to treat Irritable Bowel Syndrome with Constipation (IBS-C). It is not known if IBSRELA is safe and effective in children less than 18 years of age.
Irritable bowel syndrome with constipation (IBS-C) is a gastrointestinal disorder characterized by significant abdominal pain and constipation. IBS-C significantly impacts the health and quality of life of affected patients. The cause of IBS-C is unknown, and there are currently no specific diagnostic tests or biomarkers for detection. Therefore, IBS-C is diagnosed by symptoms and by eliminating other disorders. It is estimated that there are ~11 million people in the U.S. with IBS-C.
IMPORTANT SAFETY INFORMATION
- Do not give IBSRELA to children who are less than 6 years of age. It may harm them.
- You should not give IBSRELA to patients 6 years to less than 18 years of age. It may harm them. IBSRELA can cause severe diarrhea and your child could get severe dehydration (loss of a large amount of body water and salt).
- Do not take IBSRELA if a doctor has told you that you have a bowel blockage (intestinal obstruction).
Before you take IBSRELA, tell your doctor:
- If you have any other medical conditions
- are pregnant or plan to become pregnant. It is not known if IBSRELA will harm your unborn baby.
- are breastfeeding or plan to breastfeed. It is not known if IBSRELA passes into your breast milk. Talk with your doctor about the best way to feed your baby if you take IBSRELA®.
- Tell your doctor about all the medicines you take, including prescription and over-the-counter medicines, vitamins and herbal supplements.
Side Effects
- Diarrhea is the most common side effect of IBSRELA, and it can sometimes be severe. Stop taking IBSRELA and call your doctor if you develop severe diarrhea.
The other most common side effects of IBSRELA include:
- swelling, or a feeling of fullness or pressure in your abdomen (distension).
- gas (flatulence).
- dizziness
These are not all the possible side effects of IBSRELA. Call your doctor for medical advice about side effects.
You may report side effects to FDA at 1-800-FDA-1088. You may also report side effects to www.fda.gov/medwatch or you can report side effects to Ardelyx at 1-844-427-7352.
Please also see Medication Guide within the Full Prescribing Information.
Expanded Access
Ardelyx, Inc. is committed to the development of targeted therapies to address significant unmet medical needs. Our aim is to provide these therapies to the broadest number of patients based on the totality of data associated with obtaining regulatory approval, which is the only way to make medicines broadly available to patients by prescription from a qualified healthcare provider. The performance of clinical research allows Ardelyx to properly evaluate our investigational therapies to generate requisite safety and efficacy data to secure such an approval. Please see clinicaltrials.gov for a full listing of our ongoing clinical trials.
Currently, Ardelyx does not provide access to its investigational products outside of enrollment in clinical trials. However, Ardelyx may, in the future and in limited instances, consider expanded access to investigational products for patients residing in the United States and who may benefit from our investigational therapies currently in development.
What is IBS-C?
Irritable bowel syndrome with constipation (IBS-C) is a gastrointestinal disorder characterized by significant abdominal pain and constipation (when a bowel movement is difficult due to insufficient/decreased amount of fluid in the GI, or happens less often than normal). IBS-C significantly impacts the health and quality of life of affected patients. The cause of IBS-C is unknown, and there are currently no specific diagnostic tests or biomarkers for detection. Therefore, IBS-C is diagnosed by symptoms and by eliminating other disorders. IBS-C is similar to chronic constipation but is clinically distinct as a result of the significant abdominal pain component.
It is estimated there are up to 13 million people in the U.S. with IBS-C, depending on the diagnostic criteria employed.