Pyrukynd: Uses, Dosage & Side Effects
A first-in-class oral pyruvate kinase activator used to treat hemolytic anemia in adults with pyruvate kinase (PK) deficiency
Pyrukynd (mitapivat) is the first oral medicine approved specifically for the treatment of hemolytic anemia in adult patients with pyruvate kinase deficiency (PK deficiency), a rare inherited enzyme disorder that causes premature destruction of red blood cells. Mitapivat is a first-in-class allosteric activator of red cell pyruvate kinase (PKR) that corrects the underlying metabolic defect by stabilizing the defective enzyme in its active form. This restores the energy supply of red blood cells, reduces chronic hemolysis, increases hemoglobin concentrations, and may reduce or eliminate the need for regular blood transfusions. Pyrukynd is taken twice daily by mouth and must always be prescribed and monitored by a specialist familiar with rare hematological disorders.
Quick Facts: Pyrukynd
Key Takeaways
- Pyrukynd (mitapivat) is the first-in-class oral pyruvate kinase activator, approved for the treatment of hemolytic anemia in adult patients with pyruvate kinase (PK) deficiency, a rare inherited form of chronic hemolytic anemia.
- It is taken as a film-coated tablet twice daily with or without food; the starting dose is 5 mg twice daily and is titrated upward every 4 weeks to a maximum of 50 mg twice daily, guided by hemoglobin response and tolerability.
- Pyrukynd must never be stopped abruptly — sudden discontinuation can cause rebound acute hemolysis with a rapid drop in hemoglobin; any stop should be done via gradual tapering under specialist supervision.
- Mitapivat is a moderate inducer of CYP3A4 and can reduce the effectiveness of hormonal contraceptives; women of childbearing potential should use non-hormonal contraception, and men experience reversible decreases in testosterone and other sex hormones due to aromatase inhibition.
- Regular laboratory monitoring is essential, including hemoglobin, markers of hemolysis, liver enzymes, uric acid, and sex hormones, so that benefits and risks can be optimized over the long term.
What Is Pyrukynd and What Is It Used For?
Pyrukynd contains the active substance mitapivat, a first-in-class, orally available, small-molecule allosteric activator of red blood cell pyruvate kinase (PKR). It is authorized by the European Medicines Agency (EMA), the U.S. Food and Drug Administration (FDA), the UK Medicines and Healthcare products Regulatory Agency (MHRA), and other regulators for the treatment of pyruvate kinase deficiency (PK deficiency) in adult patients. Pyrukynd has been granted orphan drug designation for this rare hereditary condition in multiple jurisdictions.
Pyruvate kinase deficiency is a rare, inherited form of chronic hemolytic anemia caused by mutations in the PKLR gene, which encodes the red-cell and liver isoforms of the enzyme pyruvate kinase. The condition is inherited in an autosomal recessive pattern, meaning that both parents must pass on a defective PKLR gene for a child to be affected. Prevalence estimates range from approximately 1 in 20,000 to 1 in 300,000 in people of European ancestry, with somewhat higher frequencies in certain populations such as the Pennsylvania Amish. Because PK deficiency is rare, it is often underdiagnosed, and many patients experience years of unexplained anemia, jaundice, or fatigue before a definitive diagnosis is made.
Pyruvate kinase is a key enzyme in glycolysis, the metabolic pathway that generates adenosine triphosphate (ATP) in red blood cells. Unlike most other cells, mature red blood cells lack mitochondria, so they depend entirely on glycolysis for their energy supply. When PKR activity is reduced by PK deficiency, ATP production falls, 2,3-diphosphoglycerate (2,3-DPG) accumulates upstream in the pathway, and the affected red blood cells become fragile and are removed prematurely by the spleen and liver. The clinical consequences include chronic anemia, jaundice, gallstones, iron overload (partly driven by ineffective erythropoiesis and partly by chronic transfusions), splenomegaly, and osteoporosis. Some patients require long-term transfusion support.
Mitapivat works by binding to an allosteric site on the PKR tetramer, distinct from the substrate (phosphoenolpyruvate) binding site. This binding stabilizes the active tetrameric conformation of the enzyme and increases its catalytic activity, even in the presence of common PKLR mutations. The downstream effects include increased ATP generation, reduced 2,3-DPG concentration, and improved red-cell stability. In clinical trials, these molecular changes translated into measurable increases in hemoglobin, reductions in markers of hemolysis (such as indirect bilirubin, lactate dehydrogenase, and reticulocyte count), and significant reductions in transfusion burden.
Pyrukynd is approved for two principal clinical situations within PK deficiency:
- Non–transfusion-dependent adult patients with PK deficiency: In the ACTIVATE trial, mitapivat significantly increased hemoglobin compared with placebo and produced a clinically meaningful hemoglobin response in a substantial proportion of patients. For these patients, Pyrukynd can alleviate anemia-related symptoms such as chronic fatigue, exercise intolerance, jaundice, and quality-of-life impairment, and it may reduce the likelihood of future transfusion requirements.
- Transfusion-dependent adult patients with PK deficiency: In the ACTIVATE-T trial, mitapivat reduced transfusion burden by at least one-third in a meaningful proportion of regularly transfused adults, and some patients achieved complete transfusion independence during the study. In real-world practice, this can translate into fewer hospital visits, less iron overload, and improved quality of life.
Pyrukynd is not approved for the treatment of PK deficiency in children under 18 years of age, for other forms of hemolytic anemia, or for the treatment of anemia unrelated to PKR dysfunction. Clinical programs are ongoing in other hemoglobinopathies (including sickle cell disease and thalassemia), but the authorized indication at the time of publication is limited to PK deficiency in adults. Decisions regarding suitability, starting dose, titration, and monitoring should always be made by a hematologist with experience in rare hemolytic anemias.
Unlike blood transfusions or splenectomy, which address the consequences of PK deficiency, Pyrukynd targets the underlying enzymatic defect. By restoring red-cell energy metabolism, it allows affected red blood cells to survive closer to their normal 120-day lifespan. This disease-modifying approach represents a significant advance over previously available supportive care in PK deficiency.
What Should You Know Before Taking Pyrukynd?
Contraindications
There are a small number of situations in which Pyrukynd must not be used. Understanding these absolute contraindications before the start of treatment helps avoid serious adverse events.
- Hypersensitivity: Do not take Pyrukynd if you have had a serious allergic reaction to mitapivat or to any of the other ingredients (croscarmellose sodium, mannitol, magnesium stearate, microcrystalline cellulose, sodium stearyl fumarate, and the film-coating excipients).
- Use in children and adolescents: Pyrukynd is not approved for use in patients under 18 years of age. Efficacy and safety in this population have not been adequately established.
Warnings and Precautions
Stopping Pyrukynd suddenly, missing multiple doses, or rapidly lowering the dose can trigger rebound acute hemolysis (a sudden and severe destruction of red blood cells). Patients may experience rapid worsening of anemia, fatigue, shortness of breath, pronounced jaundice (yellowing of the skin and eyes), dark urine, abdominal or back pain, and tachycardia. If Pyrukynd needs to be stopped — whether because of side effects, elective surgery, or loss of efficacy — the dose must be tapered gradually under specialist supervision, with close laboratory monitoring. Never adjust or interrupt your own dose without medical advice.
Before and during treatment with Pyrukynd, tell your doctor if any of the following apply to you, as they may affect the safety or effectiveness of treatment:
- Liver disease: Transient elevations in liver enzymes (AST, ALT) have been reported with mitapivat, most commonly during dose escalation. Pyrukynd should be used with caution in patients with moderate or severe hepatic impairment and is generally not recommended for patients with severe hepatic impairment unless the expected benefit outweighs the risk. Liver function should be checked before starting treatment and regularly thereafter.
- Kidney disease: No formal dose adjustment is required for mild to moderate renal impairment, but experience in severe renal impairment and in patients on dialysis is limited. Your doctor will weigh the risks and benefits individually.
- Sex hormone changes: Mitapivat inhibits the aromatase enzyme (CYP19A1), which converts androgens to estrogens. In women, this may reduce estrone and estradiol levels; in men, it may decrease testosterone and may increase symptoms such as hot flushes, reduced libido, mood changes, or erectile problems. These changes are usually dose-related and improve after discontinuation.
- Hyperuricemia and gout: Mitapivat increases serum uric acid in a subset of patients and may unmask or worsen gout. Patients with a history of gout or uric acid kidney stones should be monitored closely.
- Bone health and osteoporosis: PK deficiency itself is associated with reduced bone mineral density. Because mitapivat can reduce estrogen levels, particular attention should be paid to bone health in postmenopausal women and in men with low baseline testosterone. Dual-energy X-ray absorptiometry (DEXA) scans and vitamin D/calcium assessment may be considered.
- Cardiovascular risk factors: Changes in estrogen levels may have implications for cardiovascular health, particularly in older adults. Your doctor will consider your individual cardiovascular risk profile.
- Psychiatric history: Insomnia, mood changes, and, rarely, depressive symptoms have been reported. Patients with a history of mental health conditions should be monitored.
- Lactose intolerance: Some film-coated formulations contain minimal amounts of excipients derived from lactose; patients with rare hereditary disorders of galactose metabolism or glucose-galactose malabsorption should consult the product label.
Your doctor will schedule regular blood tests and clinical assessments throughout your treatment to monitor hemoglobin, reticulocytes, markers of hemolysis (bilirubin, LDH, haptoglobin), liver function, uric acid, and relevant hormone levels.
Other Medications
Tell your doctor and pharmacist about every medicine you are taking, including prescription drugs, over-the-counter products, vitamins, supplements, and herbal remedies. Mitapivat is primarily metabolized by CYP3A4 and is a moderate inducer of several cytochrome P450 enzymes and UGT1A1. These metabolic effects underlie many of its clinically important drug interactions, discussed in detail in the dedicated section below.
Pregnancy and Breastfeeding
Pyrukynd is not recommended during pregnancy. Data on the use of mitapivat in pregnant women are limited, and animal reproductive studies have shown developmental toxicity at clinically relevant exposures. If you are pregnant, think you may be pregnant, or are planning a pregnancy, tell your doctor before starting Pyrukynd. The decision to continue or interrupt treatment during pregnancy must be individualized, balancing the risks of uncontrolled hemolysis against potential effects on the fetus.
Women of childbearing potential must use effective non-hormonal contraception during treatment with Pyrukynd and for at least 1 month after the last dose. Because mitapivat is a moderate CYP3A4 inducer, estrogen- and progestogen-containing hormonal contraceptives (combined oral contraceptives, patches, rings, and some injectables or implants) may become less effective and should not be relied upon as the sole method of contraception. Copper intrauterine devices (IUDs) and barrier methods with spermicide are generally suitable alternatives; your doctor can advise on the best option for your individual situation.
It is not known whether mitapivat or its metabolites are excreted in human breast milk. Because a risk to the nursing infant cannot be excluded, breastfeeding is not recommended during treatment with Pyrukynd and for a defined period after the last dose, as specified in the product information. Discuss feeding options with your healthcare team.
Driving and Operating Machinery
Pyrukynd may have a minor influence on the ability to drive and use machines. Some patients experience headache, dizziness, or insomnia, particularly at the beginning of treatment or after dose increases. If you feel any of these symptoms, avoid driving or operating machinery until they resolve.
How Does Pyrukynd Interact with Other Drugs?
Mitapivat has a clinically important pharmacokinetic profile with multiple two-way interactions. It is a substrate of CYP3A4, and drugs that inhibit or induce this enzyme can meaningfully change plasma exposure to mitapivat. At the same time, mitapivat itself is a moderate inducer of several CYP and UGT enzymes, which can lower the exposure to co-administered substrates of these enzymes. P-glycoprotein (P-gp) and BCRP transporter activity may also be affected. It is therefore essential that your doctor and pharmacist review your complete medication list before you start Pyrukynd and whenever a new medicine is introduced or stopped.
Major Interactions
| Interacting Drug or Class | Effect | Clinical Significance |
|---|---|---|
| Strong CYP3A4 inhibitors (e.g., ketoconazole, itraconazole, clarithromycin, ritonavir) | Significantly increased mitapivat plasma levels and risk of dose-related side effects | Avoid combination; if unavoidable, use the lowest dose of mitapivat and monitor closely |
| Strong CYP3A4 inducers (e.g., rifampicin, phenytoin, carbamazepine, St. John’s wort) | Substantially decreased mitapivat levels and potential loss of hematologic response | Avoid combination; if unavoidable, a dose increase of mitapivat may be needed, with careful monitoring |
| Hormonal contraceptives (estrogen- and/or progestogen-containing) | Reduced contraceptive exposure and efficacy due to CYP3A4 induction | Use a reliable non-hormonal backup method (e.g., copper IUD, barrier method with spermicide) |
| Sensitive CYP3A4 substrates with narrow therapeutic index (e.g., certain immunosuppressants, certain calcineurin inhibitors) | Decreased plasma levels of the substrate and possible loss of effect | Therapeutic drug monitoring and dose adjustment may be necessary |
Other Interactions
| Interacting Drug or Class | Effect | Clinical Significance |
|---|---|---|
| Moderate CYP3A4 inhibitors (e.g., erythromycin, fluconazole, grapefruit juice, diltiazem, verapamil) | Modest increase in mitapivat exposure | Use with caution; monitor for side effects; dose reduction may be considered |
| Moderate CYP3A4 inducers (e.g., efavirenz, bosentan, modafinil) | Moderate decrease in mitapivat exposure | Monitor hemoglobin response closely; dose increase may be considered |
| CYP2B6 substrates (e.g., bupropion, methadone, efavirenz) | Possible reduced exposure to the co-administered drug | Monitor clinical response; dose adjustment may be required |
| CYP2C8 and CYP2C9 substrates (e.g., warfarin, phenytoin, some oral antidiabetics) | Potentially decreased plasma levels and therapeutic effect | Closer INR or laboratory monitoring; dose adjustment as needed |
| UGT1A1 substrates (e.g., raltegravir, dolutegravir, irinotecan) | Altered metabolism of the co-administered drug | Clinical monitoring recommended; specialist advice as needed |
| P-glycoprotein (P-gp) substrates (e.g., digoxin, dabigatran) | Possible changes in absorption and distribution | Monitor for efficacy and toxicity; dose adjustment may be warranted |
| Aromatase inhibitors (e.g., letrozole, anastrozole) | Additive effects on estrogen reduction | Consider implications for bone health and cardiovascular risk; specialist consultation advised |
If you are admitted to hospital, undergo surgery, start anesthesia, or are treated by a new clinician, always inform them that you are taking Pyrukynd. This is particularly important because abrupt interruption during fasting or a hospital stay could precipitate acute hemolysis. Carrying a medication card or alert listing Pyrukynd is strongly recommended.
What Is the Correct Dosage of Pyrukynd?
Pyrukynd is administered as film-coated tablets that should be swallowed whole with water. The tablets must not be crushed, split, or chewed, and they can be taken with or without food. Try to take each dose at approximately the same time each day — for example, one dose in the morning and one in the evening — to keep blood levels stable. Your hematologist will determine the starting dose, titration schedule, and maximum dose based on your clinical situation, medication list, and any hepatic or renal impairment.
Adults (18 Years and Older)
Standard Titration Schedule
Week 1 to Week 4: 5 mg orally twice daily
Week 5 to Week 8: 20 mg orally twice daily (if tolerated and hemoglobin response not yet adequate)
Week 9 onwards: 50 mg orally twice daily (maximum authorized dose)
Dose escalation is typically performed every 4 weeks, allowing time for hemoglobin to stabilize and for dose-dependent side effects to be assessed. The dose should not be increased if the hemoglobin response is already adequate or if an unacceptable adverse effect occurs at a lower dose.
When to Consider Dose Reduction
A downward dose adjustment may be required in the following situations:
- Hemoglobin rising above the upper limit of normal (over-correction)
- Troublesome side effects such as persistent headache, insomnia, or sex-hormone-related symptoms
- Clinically significant elevation of liver enzymes
- Initiation of a moderate or strong CYP3A4 inhibitor
- New or worsening moderate hepatic impairment
Missed Dose
If you miss a dose by less than 4 hours, take it as soon as you remember, then continue with your regular schedule. If more than 4 hours have passed since the scheduled time, skip the missed dose and take the next dose at the usual time. Do not take two doses to make up for a missed one. If you miss several doses in a row, contact your doctor before restarting, as the risk of rebound hemolysis must be considered and you may need clinical evaluation before continuing treatment.
Stopping or Tapering Pyrukynd
If treatment needs to be stopped, your doctor will use a gradual tapering schedule, typically halving the dose every 3 to 7 days while monitoring hemoglobin closely. This minimizes the risk of rebound acute hemolysis. Tapering plans may differ depending on your current dose, hemoglobin baseline, and clinical stability.
Elderly Patients
No specific dose adjustment is required based on age alone. Older adults may, however, have more comorbidities and concomitant medications, so clinicians should pay particular attention to drug interactions, bone health, and cardiovascular risk.
Children and Adolescents
Pyrukynd is not approved for use in patients younger than 18 years. The safety and efficacy of mitapivat in children have not been established outside of clinical trials, and alternative disease-specific or supportive strategies should be considered in pediatric PK deficiency.
Hepatic and Renal Impairment
- Mild hepatic impairment (Child-Pugh A): No initial dose adjustment is typically required, but closer monitoring of liver enzymes is advised.
- Moderate hepatic impairment (Child-Pugh B): A lower starting dose may be used, with slower titration and more frequent laboratory assessments.
- Severe hepatic impairment (Child-Pugh C): Pyrukynd is generally not recommended. Use only if the anticipated benefit outweighs the potential risk and with specialist hepatology input.
- Mild to moderate renal impairment: No dose adjustment is recommended.
- Severe renal impairment or dialysis: Data are limited; use with caution and individualize therapy.
Overdose
There is limited clinical experience with overdose of mitapivat. In the event of a suspected overdose, do not try to manage the situation at home. Contact emergency services, a poison control center, or the nearest hospital emergency department immediately. Treatment is supportive and symptom-directed, including monitoring of hemoglobin, electrolytes, liver function, and vital signs. In hospital, hemodynamic and hematologic support should be provided as clinically indicated. Because of the risk of rebound hemolysis, interruption of the medicine should not be done without careful medical assessment, even after an overdose.
How Pyrukynd Should Be Administered
Pyrukynd tablets are designed for consistent, twice-daily oral administration. Patients should establish a routine that links dosing with regular daily activities (for example, with breakfast and dinner). Food does not significantly alter absorption, so the tablet can be taken with or without meals, whichever is more convenient and helps adherence. Keep a medication diary or use a reminder app to reduce the risk of missed doses, and bring your complete medication list to every medical appointment.
What Are the Side Effects of Pyrukynd?
Like all medicines, Pyrukynd can cause side effects, although not everyone experiences them. The side-effect profile has been characterized in the ACTIVATE and ACTIVATE-T phase 3 clinical trials and in post-marketing surveillance. Many side effects are dose-related and occur most frequently during dose escalation; they often improve over time or resolve with dose adjustment. Hemoglobin, liver function, uric acid, and selected hormones should be monitored throughout treatment so that emerging effects can be detected and managed early.
Side Effects by Frequency
Very Common
May affect more than 1 in 10 people
- Headache
- Insomnia (difficulty sleeping)
- Back pain
- Nausea
- Decreased estrone and estradiol (in women)
- Decreased testosterone (in men)
- Increased uric acid (hyperuricemia)
Common
May affect up to 1 in 10 people
- Fatigue
- Dizziness
- Abdominal pain
- Vomiting
- Diarrhea
- Arthralgia (joint pain)
- Myalgia (muscle pain)
- Hot flush
- Elevated liver enzymes (AST/ALT), typically transient
- Oropharyngeal pain
- Dyspnoea (shortness of breath)
Uncommon
May affect up to 1 in 100 people
- Gout flare or worsening of pre-existing gout
- Erectile dysfunction
- Decreased libido
- Mood changes or depressive symptoms
- Clinically significant hepatotoxicity (marked AST/ALT elevations)
- Uric acid kidney stones
- Rash or pruritus
Rare
May affect up to 1 in 1,000 people
- Serious hypersensitivity reactions
- Severe liver injury requiring discontinuation
- Significant reductions in bone mineral density
Not Known
Frequency cannot be estimated from available data
- Rebound acute hemolysis after abrupt dose reduction or discontinuation (a recognized class effect; frequency depends on handling)
- Longer-term effects on fertility and bone health remain under evaluation
Important Notes on Specific Side Effects
Headache and insomnia are the most common complaints in the first 4 to 8 weeks. They often resolve after the first dose level or can be managed by taking the evening dose earlier and maintaining consistent sleep hygiene. Simple analgesics such as paracetamol (acetaminophen) may be used for headache if approved by your doctor; avoid non-steroidal anti-inflammatory drugs if you have underlying hemolysis-related renal or gastrointestinal issues.
Sex-hormone changes reflect mitapivat’s off-target aromatase-inhibitory activity. In men, this can lower testosterone, cause hot flushes, reduce libido, or affect erectile function; in women, menstrual irregularities and menopausal-type symptoms may occur. These changes are usually reversible after dose reduction or discontinuation, but they have important implications for long-term bone and cardiovascular health and should be discussed with your specialist.
Hyperuricemia is thought to result from increased red-cell turnover as hemolysis stabilizes and from direct metabolic effects. Most patients remain asymptomatic, but a small number develop gout flares or uric acid stones. Hydration and, where appropriate, urate-lowering therapy (e.g., allopurinol) may be indicated.
Transaminase elevations are frequent and usually mild. Persistent elevations greater than 3 times the upper limit of normal, particularly when accompanied by symptoms or bilirubin elevation, warrant closer investigation and possible dose reduction or interruption.
If you experience any side effects, including those not listed here, tell your doctor, pharmacist, or nurse. You can also report suspected side effects directly to your national pharmacovigilance authority (e.g., EMA EudraVigilance in Europe, the FDA MedWatch program in the United States, or the MHRA Yellow Card Scheme in the United Kingdom). Reporting helps identify new safety information and protects patients worldwide.
How Should Pyrukynd Be Stored?
Pyrukynd is supplied in tamper-evident child-resistant bottles. Proper storage is essential to maintain the stability of the active substance and the integrity of the film coating.
- Temperature: Store below 30°C (86°F). The tablets do not require refrigeration.
- Protection from moisture: Keep the tablets in the original bottle with the cap tightly closed. Do not transfer the tablets to a weekly pill organizer for long periods, as this may expose them to moisture and reduce stability.
- Expiry date: Do not use after the date printed on the carton and bottle. The expiry date refers to the last day of the month indicated.
- Child safety: Always keep the container tightly closed and stored out of the sight and reach of children. Accidental ingestion by a child could cause serious harm.
- Visual inspection: Inspect the tablets before each dose. Do not use if tablets show signs of damage, discoloration, or moisture exposure.
Do not dispose of medicines in wastewater or household waste. Return unused Pyrukynd tablets to a pharmacy for safe disposal, in line with local regulations. These precautions help protect the environment from pharmaceutical contamination.
What Does Pyrukynd Contain?
Active Substance
The active substance in Pyrukynd is mitapivat, supplied as mitapivat sulfate hydrate. The 5 mg tablet contains mitapivat sulfate hydrate equivalent to 5 mg of mitapivat base. Higher-strength tablets contain 20 mg or 50 mg of mitapivat base, respectively. Mitapivat is a first-in-class small-molecule allosteric activator of red-cell pyruvate kinase (PKR) and has the molecular formula C24H26N4O3S and a molecular weight of approximately 466.6 g/mol (as the free base).
Inactive Ingredients (Excipients)
In addition to the active substance, Pyrukynd film-coated tablets contain the following inactive ingredients (the precise composition may vary slightly by region):
- Croscarmellose sodium (disintegrant)
- Mannitol (diluent)
- Microcrystalline cellulose (diluent)
- Sodium stearyl fumarate (lubricant)
- Film coating containing hypromellose, titanium dioxide (E171), macrogol/polyethylene glycol, triacetin, and iron oxide pigments (varies by strength to provide distinct tablet colors)
Appearance and Pack Sizes
Pyrukynd tablets are round or oblong, film-coated, and debossed with a strength-specific identifier. Tablet color varies by strength to reduce the risk of mix-ups during titration. Tablets are supplied in high-density polyethylene (HDPE) bottles with child-resistant closures, containing a month’s supply. Pack sizes may differ by country.
Marketing Authorization Holder and Manufacturer
Pyrukynd is developed and commercialized by Agios Pharmaceuticals. In the European Union, the marketing authorization holder is Agios Netherlands B.V. In the United States, Pyrukynd is marketed by Agios Pharmaceuticals, Inc. The manufacturing sites are listed on the carton and in the regional product information. For up-to-date information on the marketing authorization holder, batch numbers, and full excipient lists, refer to the latest Summary of Product Characteristics (EMA) or Prescribing Information (FDA) for your region.
Frequently Asked Questions About Pyrukynd
Pyrukynd (mitapivat) is used to treat hemolytic anemia caused by pyruvate kinase (PK) deficiency in adult patients. Pyruvate kinase deficiency is a rare inherited disorder in which red blood cells break down too early (hemolysis), causing chronic anemia, jaundice, fatigue, enlargement of the spleen, and sometimes a dependence on regular blood transfusions. Pyrukynd is the first approved oral treatment specifically designed for this condition and works by activating the defective pyruvate kinase enzyme so that red blood cells produce more energy and survive longer.
Pyrukynd contains mitapivat, a first-in-class allosteric activator of red cell pyruvate kinase (PKR). In pyruvate kinase deficiency, a genetic mutation in the PKLR gene produces a PKR enzyme with reduced activity, which means red blood cells cannot produce enough ATP (energy) through glycolysis and break down prematurely. Mitapivat binds to PKR at a site distinct from the active site and stabilizes the active tetrameric form of the enzyme. This increases enzyme activity, restores ATP production, lowers 2,3-DPG, and helps red blood cells live a more normal lifespan.
Pyrukynd is taken by mouth as a film-coated tablet, twice daily (approximately every 12 hours), with or without food. Treatment usually starts at 5 mg twice daily and is titrated upward every 4 weeks based on hemoglobin response and tolerability, up to a maximum dose of 50 mg twice daily. Tablets should be swallowed whole with water and must not be crushed, split, or chewed. It is important to take the medicine at approximately the same times each day and never to stop or pause Pyrukynd without medical supervision.
The most common side effects of Pyrukynd include headache, back pain, nausea, increased uric acid (hyperuricaemia), and changes in sex hormone levels including decreased estrone, estradiol, and testosterone in men. Many patients also experience insomnia, fatigue, and transient increases in liver enzymes early in treatment. Most side effects are mild to moderate and improve with dose adjustment or over time. Monitoring includes regular blood tests for hemoglobin, liver function, uric acid, and hormones.
No. You must not stop Pyrukynd suddenly or miss multiple doses without medical advice. Abrupt discontinuation or interruption of Pyrukynd can trigger rebound acute hemolysis (rapid red blood cell destruction) with a sudden drop in hemoglobin, which may be severe. When Pyrukynd needs to be stopped, the dose is usually tapered down gradually over at least 1 to 2 weeks with close monitoring of hemoglobin. Always follow the specific tapering schedule prescribed by your hematologist.
Yes. Pyrukynd is a moderate inducer of CYP3A4 and can reduce the effectiveness of hormonal contraceptives that contain estrogens and/or progestogens, including combined oral contraceptives, contraceptive patches, rings, and some injectables or implants. Women of childbearing potential should use a reliable non-hormonal contraceptive method (for example, a copper IUD) or a barrier method in addition to hormonal contraception during treatment with Pyrukynd and for a defined period after stopping. Discuss the best contraceptive strategy with your doctor before starting therapy.
Pyrukynd is not recommended during pregnancy unless clearly necessary. There are limited data on the use of mitapivat in pregnant women. Animal studies have shown developmental toxicity at clinically relevant exposures. Women of childbearing potential must use effective non-hormonal contraception during treatment and for at least one month after the last dose. If you become pregnant while taking Pyrukynd, contact your doctor immediately so that the treatment plan can be reviewed. Pyrukynd should not be used during breastfeeding, as it is unknown whether mitapivat passes into human breast milk.
References
- European Medicines Agency (EMA). Pyrukynd (mitapivat) – Summary of Product Characteristics. Last updated 2025. Available from: EMA EPAR – Pyrukynd.
- U.S. Food and Drug Administration (FDA). PYRUKYND (mitapivat) US Prescribing Information. Revised 2024. Available from: FDA Drug Label.
- Al-Samkari H, Galactéros F, Glenthøj A, et al. Mitapivat versus placebo for pyruvate kinase deficiency (ACTIVATE). N Engl J Med. 2022;386(15):1432–1442. doi:10.1056/NEJMoa2116634.
- Glenthøj A, van Beers EJ, Al-Samkari H, et al. Mitapivat in adult patients with pyruvate kinase deficiency receiving regular transfusions (ACTIVATE-T). Am J Hematol. 2022;97(12):1517–1527. doi:10.1002/ajh.26699.
- Grace RF, Bianchi P, van Beers EJ, et al. Clinical spectrum of pyruvate kinase deficiency: data from the Pyruvate Kinase Deficiency Natural History Study. Blood. 2018;131(20):2183–2192. doi:10.1182/blood-2017-10-810796.
- Kung C, Hixon J, Kosinski PA, et al. AG-348 enhances pyruvate kinase activity in red blood cells from patients with pyruvate kinase deficiency. Blood. 2017;130(11):1347–1356. doi:10.1182/blood-2016-11-753525.
- van Beers EJ, van Straaten S, Morton DH, et al. Prevalence and management of iron overload in pyruvate kinase deficiency. Haematologica. 2019;104(2):e51–e53.
- Bianchi P, Fermo E, Glader B, et al. Addressing the diagnostic gaps in pyruvate kinase deficiency: consensus recommendations. Am J Hematol. 2019;94(1):149–161.
- National Institute for Health and Care Excellence (NICE). Mitapivat for treating pyruvate kinase deficiency in adults. Technology appraisal guidance. 2024.
- World Health Organization (WHO). Model list of essential medicines – update on orphan therapies for rare hemolytic anemias. Geneva: WHO; 2024.
Editorial Team
This article was written and reviewed by the iMedic Medical Editorial Team, comprising licensed specialist physicians with expertise in hematology, rare disease care, and clinical pharmacology.
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