Filspari (sparsentan): Benefits, Uses, Dosage, Side Effects, Cost

What is the drug Filspari used for?

Filspari (sparsentan) is a prescription medication designed to reduce protein in the urine (proteinuria) in adults who have primary IgA nephropathy and are at risk of their condition rapidly deteriorating. This drug is not intended for use in children, and its safety and efficacy in pediatric populations have not been established.

The U.S. Food and Drug Administration (FDA) granted accelerated approval to Filspari based on its ability to reduce proteinuria in affected adults. However, further approval may be contingent on the results of an ongoing study aimed at determining whether Filspari can also slow the decline in kidney function.

As a medication specifically targeted at addressing primary IgA nephropathy and its associated complications, Filspari offers hope for adults with this condition to potentially stabilize their kidney function and improve their overall health. Filspari is manufactured by Travere Therapeutics.


Dosing information for Filspari in adults with IgA nephropathy is as follows:

•        Initial Dose: 200 mg orally once daily for 14 days.

•        Maintenance Dose: After the initial 14-day period, the dosage is increased to 400 mg orally once daily, as long as it is well-tolerated.

•        Prior to starting treatment with Filspari, patients should discontinue the use of renin-angiotensin-aldosterone system (RAAS) inhibitors, endothelin receptor antagonists (ERAs), or aliskiren.

The approved use of Filspari is for reducing proteinuria in adults with primary IgA nephropathy (IgAN) who are at risk of rapid disease progression. This usually includes patients with a urine protein-to-creatinine ratio (UPCR) of 1.5 g/g or higher. The approval for this indication is based on accelerated approval, which was granted due to the observed reduction in proteinuria. However, it has not been conclusively established whether Filspari also slows the decline of kidney function in patients with IgAN. For this reason, continued approval for this particular indication may be subject to further confirmation and description of clinical benefits through additional clinical trials.

What should I avoid while taking Filspari?

While taking Filspari, it is crucial to avoid the following:

  • Pregnancy: Do not become pregnant while taking Filspari. If you miss a menstrual period or suspect that you might be pregnant, contact your healthcare provider immediately. As previously mentioned, Filspari has the potential to cause serious birth defects if taken during pregnancy.
  • Breastfeeding: It is not known if Filspari passes into breast milk. Therefore, if you are taking Filspari, it is advised not to breastfeed. To determine the best way to feed your baby during treatment with Filspari, have a discussion with your healthcare provider.

By avoiding pregnancy and breastfeeding while on Filspari, patients can reduce the risk of potential complications and ensure the safety of both themselves and their babies. It is essential to follow the guidance provided by healthcare professionals and adhere to the precautions to promote the best possible outcomes during treatment with Filspari.

Side effects

Filspari may cause several possible side effects, including:

1.      Liver problems: Filspari can potentially cause liver problems. It is essential to be aware of any signs or symptoms of liver issues, such as nausea, vomiting, pain on the upper right side of the stomach area, tiredness, loss of appetite, yellowing of the skin or eyes (jaundice), dark “tea-colored” urine, fever, or itching. If any of these symptoms occur during Filspari treatment, it is crucial to inform your healthcare provider immediately.

2.      Serious birth defects: Taking Filspari during pregnancy can lead to serious birth defects. It is of utmost importance that patients do not become pregnant while on Filspari, and they must use effective birth control methods throughout treatment and for one month after discontinuing the medication. If a patient misses a menstrual period or suspects pregnancy, they should contact their healthcare provider promptly.

3.      Low blood pressure: During Filspari treatment, low blood pressure may occur. This can be common but can also be a serious side effect. Patients should be vigilant and report any symptoms of low blood pressure, such as feeling dizzy, light-headed, or faint, to their healthcare provider. Additionally, staying hydrated during Filspari treatment is essential to manage this side effect.

4.      Worsening of kidney function: Filspari may lead to a worsening of kidney function in some patients. To monitor this potential effect, healthcare providers will regularly check kidney function during Filspari treatment.

5.      Increased potassium in your blood: Elevated potassium levels can be a common side effect of Filspari treatment and may also be serious. As a precaution, healthcare providers will regularly check the patient’s potassium blood levels during Filspari treatment.

6.      Fluid retention: Filspari can cause the body to retain excess water, leading to fluid retention. If a patient experiences unusual weight gain or swelling in their ankles or legs, it is crucial to inform their healthcare provider immediately.

7.      Peripheral edema: Peripheral edema is a common side effect of Filspari, resulting in swelling of the hands, legs, ankles, and feet. While this side effect is frequent, patients should still inform their healthcare provider about it.

8.      Dizziness: Dizziness can be experienced by some patients taking Filspari.

9.      Low red blood cells (anemia): Filspari can cause low red blood cell count, resulting in anemia. This condition may lead to fatigue and other related symptoms.

It is important to note that the list above may not include all possible side effects of Filspari. Patients should consult their healthcare provider and refer to the medication’s prescribing information for a comprehensive list of side effects and further guidance. If patients experience any side effects or have concerns during Filspari treatment, they should seek medical advice promptly.

What drugs interact with Filspari?

Interactions between medications can potentially affect how they work or lead to adverse effects. Before starting Filspari or any other medication, it is essential to inform your healthcare provider about all the medications you are currently taking, including prescription drugs, over-the-counter medications, vitamins, supplements, and herbal products. Your healthcare provider can then assess the potential drug interactions and make appropriate adjustments to ensure your safety and the effectiveness of the treatment.

Specifically, some medications may interact with Filspari, such as:

1.      Angiotensin receptor blockers (ARBs): Taking Filspari with ARBs may lead to an increased risk of low blood pressure.

2.      Endothelin receptor antagonists (ERAs): Concurrent use of Filspari with ERAs may also increase the risk of low blood pressure.

3.      Aliskiren: Combining Filspari with aliskiren may result in an elevated risk of low blood pressure.

4.      Nonsteroidal anti-inflammatory drugs (NSAIDs): Taking NSAIDs with Filspari may lead to an increased risk of kidney problems and elevated potassium levels in the blood.

5.      Medications containing potassium: Taking potassium-containing medications, supplements, or salt substitutes along with Filspari may lead to an increased risk of elevated potassium levels in the blood.

It is essential to follow your healthcare provider’s advice and inform them of any changes in your medication regimen, as they will be able to determine if any potential interactions may occur and adjust your treatment plan accordingly. This way, you can minimize the risks and optimize the benefits of Filspari therapy. Always consult with your healthcare provider before starting, stopping, or changing any medications to ensure safe and effective treatment.

How much does Filspari cost?

Filspari cost $9,900 per month. This pricing strategy positions Filspari as a more cost-effective option compared to Tarpeyo, which currently costs $14,160 per month, resulting in an annual expense of $170,000.

The competitive pricing of Filspari aims to make this innovative treatment more accessible and affordable to patients in need of effective therapy for their medical conditions. By offering a more budget-friendly alternative, the hope is that Filspari will provide substantial relief to patients and alleviate some of the financial burdens associated with medical expenses.

Furthermore, this pricing decision is likely to be a crucial factor in the healthcare market, as it impacts not only patients but also healthcare providers, insurers, and policymakers. The affordability of Filspari could potentially lead to more significant adoption rates and a broader reach to patients with the specified medical condition, thereby enhancing patient outcomes and overall healthcare efficiency.

The pricing of medications often involves a complex evaluation of various factors, including research and development costs, manufacturing expenses, market demand, competition, and regulatory requirements. The ultimate goal is to strike a balance between affordability for patients and sustainability for the pharmaceutical company, ensuring the continued availability and development of essential medications.

Filspari Benefits

Filspari offers several potential benefits for patients with specific medical conditions, particularly primary immunoglobulin A nephropathy (IgAN) in adults who are at risk of rapid disease progression. Some of the benefits of Filspari include:

1.      Reducing Proteinuria: Filspari is designed to lower proteinuria, which is the presence of excessive protein in the urine. High levels of proteinuria are often associated with kidney damage and can be a marker of disease severity. By reducing proteinuria, Filspari may help in preserving kidney function and slowing the progression of IgAN.

2.      Delaying Disease Progression: In patients with IgAN who are at risk of rapid disease progression, Filspari may provide a valuable treatment option to delay the worsening of kidney function. Slowing the progression of IgAN can lead to better long-term outcomes for patients, helping to maintain kidney health and potentially delaying the need for more aggressive treatments, such as dialysis or kidney transplantation.

3.      Improved Quality of Life: Managing IgAN and its potential complications can significantly impact a patient’s quality of life. By addressing the underlying disease process and potentially stabilizing kidney function, Filspari may contribute to an improved quality of life for affected individuals. This could mean fewer symptoms related to kidney dysfunction and a reduced need for frequent medical interventions.

4.      Cost-Effective Treatment: As previously mentioned, Filspari is priced lower than some alternative treatments for IgAN. The more cost-effective pricing may increase accessibility to this medication for patients and alleviate some of the financial burdens associated with treatment.

5.      Improved Compliance: Filspari’s once-daily dosing schedule may enhance patient compliance with the treatment regimen. Simplifying the dosing routine can improve adherence to the medication, leading to more consistent therapy and potentially better treatment outcomes.

It is essential to note that the specific benefits of Filspari can vary depending on individual patient characteristics and medical conditions. Additionally, the benefits of Filspari should be carefully balanced with its potential risks and side effects, which were previously discussed.


Dr. Oche Otorkpa PG Cert, MPH, PhD

Dr. Oche is a seasoned Public Health specialist who holds a post graduate certificate in Pharmacology and Therapeutics, an MPH, and a PhD both from Texila American University. He is a member of the International Society of Substance Use Professionals and a Fellow of the Royal Society for Public Health in the UK. He authored two books: "The Unseen Terrorist," published by AuthorHouse UK, and "The Night Before I Killed Addiction."
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