Kinpeygo: Uses, Dosage & Side Effects

What Is Kinpeygo and What Is It Used For?

Kinpeygo contains the active substance budesonide, a potent synthetic glucocorticoid with high topical anti-inflammatory activity and a favorable pharmacokinetic profile characterized by extensive first-pass hepatic metabolism. While budesonide has been available for decades in various formulations for conditions such as asthma (Pulmicort), inflammatory bowel disease (Entocort, Budenofalk), and eosinophilic esophagitis (Jorveza), Kinpeygo represents a fundamentally different formulation specifically engineered for the treatment of IgA nephropathy. The key innovation lies in its modified-release capsule technology, which uses an enteric coating system designed to release budesonide in the distal ileum rather than in the proximal gastrointestinal tract.

IgA nephropathy, also known as Berger's disease, is the most common primary glomerulonephritis worldwide, affecting an estimated 2.5 per 100,000 adults annually. It is caused by the deposition of immunoglobulin A (IgA) immune complexes in the glomerular mesangium of the kidneys, leading to inflammation, scarring (fibrosis), and progressive loss of kidney function. The disease follows a variable clinical course: while some patients maintain stable kidney function for decades, approximately 20–40% of patients progress to end-stage kidney disease (ESKD) requiring dialysis or kidney transplantation within 10–20 years of diagnosis. Risk factors for rapid progression include persistent proteinuria exceeding 1 g/day, hypertension, reduced eGFR at diagnosis, and certain histological features on kidney biopsy (including the Oxford MEST-C classification scores).

The pathogenesis of IgA nephropathy is understood through the "multi-hit hypothesis," which describes a cascade of four immunological events. The first hit involves the overproduction of galactose-deficient IgA1 (Gd-IgA1) by mucosal B cells, primarily in the gut-associated lymphoid tissue (GALT) of the ileum. This abnormally glycosylated IgA1 enters the circulation and is recognized by anti-glycan autoantibodies (the second hit), forming pathogenic immune complexes (the third hit). These immune complexes deposit in the glomerular mesangium (the fourth hit), where they activate mesangial cells, trigger complement activation, and initiate an inflammatory response that leads to glomerular injury, proteinuria, and progressive kidney damage.

Kinpeygo directly addresses the first hit of this pathogenic cascade. By delivering budesonide to the ileum, where the highest concentration of Peyer's patches and mucosal B cells resides, Kinpeygo modulates the local immune response and reduces the production of Gd-IgA1 at its source. This targeted approach is conceptually distinct from systemic immunosuppression with conventional corticosteroids or other immunosuppressive agents, which suppress the immune system broadly and carry a higher burden of side effects. Because budesonide undergoes approximately 90% first-pass metabolism in the liver after absorption from the ileum, the systemic bioavailability is low (approximately 10%), resulting in predominantly local mucosal effects with reduced systemic glucocorticoid exposure compared to prednisone or prednisolone.

The clinical efficacy of Kinpeygo was established in the NefIgArd trial, a landmark phase III, randomized, double-blind, placebo-controlled study that enrolled 364 adults with biopsy-confirmed IgA nephropathy and persistent proteinuria (UPCR ≥ 0.8 g/g) despite optimized RAS inhibitor therapy. The trial was conducted across 20 countries in North America, Europe, and Asia-Pacific. Patients were randomized 1:1 to receive Kinpeygo 16 mg/day or matching placebo for 9 months, followed by a 2-week taper and a subsequent 15-month observational follow-up period.

At 9 months, Kinpeygo reduced the UPCR by 34% relative to placebo (p < 0.0001), with a geometric least squares mean ratio of 0.66 favoring Kinpeygo. Crucially, the full two-year data from NefIgArd demonstrated that the proteinuria reduction translated into a meaningful preservation of kidney function: the total eGFR slope from baseline to month 24 showed a treatment benefit of 3.87 mL/min/1.73 m² favoring Kinpeygo (p = 0.0002), and the chronic eGFR slope (from month 3 to month 24, which excludes the early hemodynamic effects) showed a benefit of 2.47 mL/min/1.73 m² (p = 0.0093). At month 24, the overall eGFR treatment difference was 5.05 mL/min/1.73 m² in favor of Kinpeygo. These results suggest that Kinpeygo provides sustained kidney protection even after treatment discontinuation.

Kinpeygo was first approved by the European Medicines Agency (EMA) in July 2022 and received conditional approval. In the United States, the same formulation is marketed under the brand name TARPEYO and received accelerated approval from the FDA in December 2021, with full approval granted in December 2023 based on the confirmatory NefIgArd two-year data. Kinpeygo represents a significant advancement in the treatment of IgA nephropathy, which previously had no specifically approved therapies in most countries and relied on off-label use of systemic corticosteroids and immunosuppressants.

What Should You Know Before Taking Kinpeygo?

Contraindications

Kinpeygo is contraindicated in patients with known hypersensitivity to budesonide or any of the excipients in the formulation. The capsule contains sugar spheres (sucrose and maize starch), hypromellose, polyethylene glycol, citric acid, ethyl acrylate, methyl methacrylate, and other polymeric coating materials. If you have a known allergy to any of these substances, you must not use Kinpeygo. Additionally, Kinpeygo must not be used concomitantly with strong CYP3A4 inhibitors such as ketoconazole, itraconazole, cobicistat, ritonavir, nelfinavir, or clarithromycin, as these drugs can increase systemic budesonide exposure by several-fold, significantly amplifying the risk of corticosteroid-related side effects.

Kinpeygo is also contraindicated in patients with concomitant use of grapefruit juice in large amounts, as grapefruit contains furanocoumarins that inhibit intestinal CYP3A4 and can increase budesonide absorption. Patients should avoid consuming grapefruit or grapefruit juice during the entire treatment period.

Warnings and Precautions

Before starting Kinpeygo, discuss the following with your healthcare provider:

• Infections: Corticosteroids, including budesonide, suppress the immune system and can increase susceptibility to new infections or reactivation of latent infections, including tuberculosis, fungal infections, bacterial infections, and viral infections. Avoid close contact with individuals who have chickenpox or measles during treatment. If you are exposed to these infections while on Kinpeygo, seek medical advice immediately, as these diseases can take a severe course in immunocompromised patients. Inform your doctor if you have any active or chronic infection before starting treatment.
• Liver disease: Budesonide is metabolized primarily by the liver via CYP3A4 enzymes. In patients with severe hepatic impairment (Child-Pugh class C), systemic exposure to budesonide may be significantly increased due to reduced first-pass metabolism. Kinpeygo has not been studied in patients with severe hepatic impairment and should be used with caution in patients with moderate hepatic impairment (Child-Pugh class B). Your doctor may need to monitor you more closely and adjust your treatment plan accordingly.
• Adrenal suppression: Systemic absorption of budesonide, even from the targeted-release formulation, can suppress the hypothalamic-pituitary-adrenal (HPA) axis, particularly during prolonged treatment. This can result in reduced cortisol production by the adrenal glands. If you are transferring from a systemic corticosteroid (such as prednisone) to Kinpeygo, adrenal insufficiency symptoms may emerge as the systemic steroid is withdrawn. Symptoms include fatigue, headache, nausea, vomiting, joint pain, and muscle weakness.
• Diabetes mellitus: Corticosteroids can increase blood glucose levels and may worsen pre-existing diabetes or unmask latent diabetes. If you have diabetes or are at risk of developing diabetes, your blood sugar levels should be monitored regularly during treatment with Kinpeygo.
• Bone health: Long-term corticosteroid use is associated with decreased bone mineral density and an increased risk of osteoporosis and fractures. Although Kinpeygo has lower systemic exposure than conventional corticosteroids, patients with risk factors for osteoporosis (post-menopausal women, elderly patients, patients with a family history of osteoporosis, patients on other bone-depleting medications) should discuss bone-protective measures with their doctor.
• Eye conditions: Corticosteroids can cause or exacerbate glaucoma (elevated intraocular pressure) and posterior subcapsular cataracts. If you have a history of these conditions, regular ophthalmological monitoring is recommended during treatment.
• Vaccinations: Patients on immunosuppressive doses of corticosteroids should not receive live or live-attenuated vaccines (such as the live oral polio vaccine, live influenza vaccine, or BCG vaccine), as the immune response may be insufficient and there is a risk of disseminated infection from the vaccine strain. Inactivated vaccines can be administered during treatment, although the immune response may be diminished.

Pregnancy and Breastfeeding

Kinpeygo should not be used during pregnancy unless the potential benefit to the mother justifies the potential risk to the fetus. Animal reproductive studies with budesonide have shown adverse effects, including cleft palate, skeletal abnormalities, and reduced fetal weight, at doses exceeding the recommended human dose. Although epidemiological data from pregnant women exposed to inhaled budesonide (for asthma) have not shown an increased risk of congenital malformations, the oral modified-release formulation used in Kinpeygo has not been specifically studied in pregnant women. As glucocorticoids cross the placenta, there is a theoretical risk of adrenal suppression in the newborn if the mother receives corticosteroid treatment during late pregnancy. Women of childbearing potential should use effective contraception during treatment with Kinpeygo.

Budesonide is excreted in human breast milk, although the amount transferred to the nursing infant is expected to be low due to the low systemic bioavailability of the oral modified-release formulation. A risk-benefit assessment should be made in consultation with your doctor, weighing the benefits of breastfeeding for the infant against the benefits of Kinpeygo treatment for the mother. If Kinpeygo is used during breastfeeding, the infant should be monitored for signs of adrenal suppression.

Children and Adolescents

The safety and efficacy of Kinpeygo have not been established in children and adolescents under 18 years of age. IgA nephropathy in the pediatric population may have different disease characteristics and progression patterns compared to adults, and treatment decisions for pediatric patients should be made by a specialist nephrologist experienced in managing glomerular diseases in children. Kinpeygo is not recommended for use in this age group until appropriate clinical data become available.

Driving and Operating Machinery

Kinpeygo has no known effect on the ability to drive or operate machinery. Based on its pharmacological profile and the side effects observed in clinical trials, it is not expected to impair cognitive function, reaction time, or motor coordination. However, if you experience any adverse effects such as dizziness or visual disturbances during treatment, you should refrain from driving or operating heavy machinery until these symptoms resolve.

How Does Kinpeygo Interact with Other Drugs?

Budesonide, the active substance in Kinpeygo, is predominantly metabolized by the cytochrome P450 enzyme CYP3A4 in the liver and, to a lesser extent, in the gut wall. After oral administration and absorption from the ileum, budesonide undergoes extensive first-pass metabolism, resulting in a systemic bioavailability of approximately 10%. This high first-pass effect is both the reason for Kinpeygo's favorable safety profile and the mechanism through which drug interactions can have clinically significant consequences. Any drug that inhibits CYP3A4 will reduce the first-pass metabolism of budesonide, increasing its systemic bioavailability and exposing the patient to higher corticosteroid levels than intended.

The most clinically important interaction is with strong CYP3A4 inhibitors. In a pharmacokinetic study, concomitant administration of oral budesonide with ketoconazole (a prototypical strong CYP3A4 inhibitor) increased systemic exposure to budesonide approximately 6-fold. This magnitude of increase can convert the intended local mucosal effect of Kinpeygo into a systemic corticosteroid effect, with all the associated risks of Cushing's syndrome, adrenal suppression, hyperglycemia, and immunosuppression.

Major Interactions

The concomitant use of Kinpeygo with strong CYP3A4 inhibitors is contraindicated. This category includes several commonly prescribed medications: ketoconazole and itraconazole (antifungals), ritonavir, cobicistat, and nelfinavir (HIV protease inhibitors and pharmacokinetic boosters), and clarithromycin at high doses. These drugs can increase systemic budesonide exposure by 3- to 8-fold, transforming the intended local mucosal effect into a fully systemic corticosteroid effect. Patients on these medications who require treatment for IgA nephropathy should discuss alternative treatment strategies with their nephrologist.

If a patient requires a short course of a strong CYP3A4 inhibitor for a serious infection (such as clarithromycin for a specific bacterial infection), the potential interaction should be carefully weighed against the clinical need. In some cases, temporary discontinuation of Kinpeygo may be considered, although this must be done under medical supervision with appropriate tapering to avoid adrenal insufficiency.

Minor Interactions

Moderate CYP3A4 inhibitors, including erythromycin, diltiazem, verapamil, and fluconazole, can modestly increase budesonide exposure (approximately 2- to 3-fold). While not contraindicated, concomitant use requires careful monitoring for corticosteroid side effects such as edema, weight gain, elevated blood glucose, and mood changes. Your doctor may choose to reduce the Kinpeygo dose or increase monitoring frequency if co-administration is necessary.

CYP3A4 inducers such as rifampicin, carbamazepine, phenytoin, and phenobarbital can accelerate the metabolism of budesonide, potentially reducing its efficacy. Rifampicin has been shown to decrease budesonide exposure by approximately 60%. If a CYP3A4 inducer is essential for the management of a concomitant condition, the treating physician should consider whether the reduced efficacy of Kinpeygo is clinically acceptable or whether alternative therapies should be explored.

Importantly, there are no significant pharmacokinetic interactions between Kinpeygo and the ACE inhibitors or angiotensin receptor blockers (ARBs) that form the standard backbone of IgA nephropathy management. Patients should continue their optimized RAS inhibitor therapy throughout and after Kinpeygo treatment. Similarly, common medications such as statins, proton pump inhibitors, and most antihypertensives can be used alongside Kinpeygo without dose adjustment.

What Is the Correct Dosage of Kinpeygo?

Adults

The capsules must be swallowed whole with a glass of water. They must not be crushed, chewed, broken, or opened, as this would destroy the modified-release coating and result in premature release of budesonide in the wrong part of the gastrointestinal tract, reducing efficacy and potentially increasing side effects. The timing of administration is important: Kinpeygo should be taken at least 1 hour before a meal, preferably in the morning. Food can alter the release characteristics of the modified-release coating and should be avoided around the time of dosing.

Treatment with Kinpeygo should be initiated and supervised by a physician experienced in the management of glomerular kidney diseases. Patients should already be receiving a maximally tolerated dose of a RAS inhibitor (ACE inhibitor or ARB) for at least 90 days before starting Kinpeygo, as RAS inhibition is the standard of care for proteinuria reduction in IgA nephropathy and was a prerequisite for enrollment in the NefIgArd trial.

Children

Kinpeygo is not approved for use in children and adolescents under 18 years of age. There are no clinical data supporting the safety or efficacy of this formulation in pediatric patients with IgA nephropathy. Dosing in pediatric patients has not been established, and extrapolation from adult data is not recommended due to potential differences in disease pathophysiology, drug metabolism, and growth-related considerations in the developing kidney. Pediatric patients with IgA nephropathy should be managed by specialist pediatric nephrologists using evidence-based treatment protocols appropriate for their age group.

Elderly

No dose adjustment is generally required in elderly patients (65 years and older) based on age alone. However, elderly patients may be more susceptible to the adverse effects of corticosteroids, including osteoporosis, diabetes, hypertension, and susceptibility to infections. The NefIgArd trial included patients up to 70 years of age, but the number of patients over 65 was limited. Elderly patients should be monitored more closely during treatment, with particular attention to bone density, blood glucose levels, blood pressure, and signs of infection. Kidney function and proteinuria should be assessed regularly to evaluate treatment response.

Missed Dose

If you miss a dose of Kinpeygo, take it as soon as you remember on the same day, provided it is still at least 1 hour before a meal. If it is already close to the time of your next dose, skip the missed dose and resume your regular dosing schedule the following morning. Do not take a double dose to make up for a missed dose. If you miss doses frequently, speak to your doctor or pharmacist, as consistent daily dosing is important for maintaining the therapeutic effect of Kinpeygo on proteinuria reduction.

Overdose

In the clinical trial program, some patients inadvertently received higher doses than intended without acute adverse events. However, prolonged exposure to supratherapeutic doses of budesonide would be expected to produce dose-dependent corticosteroid side effects. If overdose is suspected, treatment should be supportive, and corticosteroid-related adverse effects should be managed as clinically indicated. There may be a need for gradual dose reduction rather than abrupt cessation to avoid precipitating adrenal insufficiency.

What Are the Side Effects of Kinpeygo?

Like all medicines, Kinpeygo can cause side effects, although not everybody gets them. The side effect profile of Kinpeygo reflects the pharmacological activity of budesonide as a corticosteroid, but the targeted-release formulation is designed to limit systemic exposure and thereby reduce the incidence and severity of typical corticosteroid side effects compared to conventional oral prednisone or prednisolone. In the NefIgArd trial, the overall incidence of adverse events was moderately higher in the Kinpeygo group compared to placebo, but serious adverse events were comparable between groups, and the discontinuation rate due to adverse events was low.

The following side effects have been reported with Kinpeygo in clinical trials, organized by frequency according to the standard MedDRA convention:

It is important to understand the clinical context of these side effects. In the NefIgArd trial, the incidence of hypertension was higher in the Kinpeygo group, but many patients with IgA nephropathy already have pre-existing hypertension as part of their kidney disease. Blood pressure should be monitored regularly during treatment, and antihypertensive medications should be adjusted as needed. Peripheral edema and weight gain are common class effects of corticosteroids related to sodium and fluid retention. These effects were generally mild to moderate in severity and manageable with dietary sodium restriction and, if necessary, diuretic therapy.

The dermatological side effects (acne, dermatitis, hirsutism) reflect the androgenic and immunomodulatory effects of corticosteroids on the skin. These are typically cosmetic in nature and resolve after treatment discontinuation. Facial puffiness (moon face) is a recognized corticosteroid effect that may develop gradually during the treatment course and generally resolves within weeks to months after stopping Kinpeygo.

Importantly, the risk of serious infections with Kinpeygo was not significantly elevated compared to placebo in the NefIgArd trial, which distinguishes it from conventional systemic immunosuppressive therapies used in IgA nephropathy. However, patients should remain vigilant for signs of infection (fever, persistent cough, unusual fatigue, pain during urination) and report these to their doctor promptly. The risk of opportunistic infections is lower with Kinpeygo than with systemic prednisone or mycophenolate mofetil, but it is not zero.

How Should You Store Kinpeygo?

Proper storage of Kinpeygo is essential to maintain the integrity of the modified-release coating, which is critical for the drug's targeted delivery to the ileum. The capsules should be stored at temperatures not exceeding 25°C (77°F). Do not store Kinpeygo in a refrigerator or freezer, as extreme cold can affect the stability of the enteric coating. The capsules should be kept in their original blister packaging until the time of use, as the blister provides protection from moisture and light, both of which can degrade the modified-release coating and the active substance.

Do not transfer Kinpeygo capsules to a pill organizer or any other container, as this removes the moisture protection provided by the blister packaging. Keep the medicine out of the sight and reach of children. Do not use Kinpeygo after the expiration date stated on the carton and blister after "EXP." The expiration date refers to the last day of that month.

Do not dispose of unused or expired medicines in household waste or down the drain. Return any unused capsules to your pharmacist for proper disposal according to local regulations. Proper disposal of medicines helps protect the environment and prevents accidental exposure.

What Does Kinpeygo Contain?

Each Kinpeygo 4 mg modified-release hard capsule contains 4 mg of budesonide as the active substance. Budesonide is a synthetic non-halogenated glucocorticoid with the chemical name 16α,17α-butylidenedioxy-11β,21-dihydroxypregna-1,4-diene-3,20-dione. It is a mixture of two epimers, 22R and 22S, with the 22R epimer being approximately twice as potent as the 22S epimer in terms of glucocorticoid receptor binding affinity.

The modified-release coating system is a key component of the Kinpeygo formulation. The capsule contains coated granules designed to resist dissolution in the acidic environment of the stomach and the neutral pH of the proximal small intestine. The enteric coating is formulated to dissolve at the pH found in the distal ileum (approximately pH 6.8–7.2), thereby releasing budesonide at the site of Peyer's patches where the pathogenic Gd-IgA1 is produced. This targeted release is what distinguishes Kinpeygo from other budesonide formulations.

The excipients (inactive ingredients) in Kinpeygo capsules include:

• Capsule content: Sugar spheres (sucrose and maize starch), hypromellose, polyethylene glycol 6000 (macrogol 6000), citric acid monohydrate, ethyl acrylate-methyl methacrylate copolymer (2:1), talc, triethyl citrate
• Capsule shell: Gelatin, titanium dioxide (E171), red iron oxide (E172), yellow iron oxide (E172)
• Printing ink: Shellac, black iron oxide (E172), propylene glycol, concentrated ammonia solution

Patients with known fructose intolerance, glucose-galactose malabsorption, or sucrase-isomaltase insufficiency should note that the capsules contain sugar spheres made from sucrose. The amount of sucrose per dose (4 capsules) is small but should be considered. The gelatin capsule shell is derived from animal sources, which may be relevant for patients with dietary or religious restrictions. There is no lactose, gluten, or peanut-derived ingredients in the formulation.