Lanvis (Thioguanine)
Cytotoxic Antimetabolite for Acute Leukaemia
Quick Facts About Lanvis
Key Takeaways About Lanvis (Thioguanine)
- Specialist-only chemotherapy: Lanvis is a cytotoxic drug prescribed exclusively by haematologists and oncologists for acute leukaemia treatment as part of combination chemotherapy regimens
- Bone marrow suppression is expected: Thioguanine reduces blood cell production, requiring regular blood count monitoring throughout treatment to manage infection and bleeding risk
- Liver toxicity with long-term use: Prolonged thioguanine use is associated with hepatic veno-occlusive disease (VOD); liver function must be monitored regularly
- TPMT and NUDT15 testing recommended: Patients with inherited deficiency of TPMT or NUDT15 enzymes are at significantly higher risk of severe toxicity and may require dose reduction
- Contraception is essential: Thioguanine can damage sperm and eggs; both male and female patients must use reliable contraception during and after treatment
What Is Lanvis and What Is It Used For?
Lanvis contains thioguanine, a cytotoxic (cell-killing) medicine belonging to the antimetabolite group of chemotherapy drugs. It is used to treat acute leukaemias – cancers of the blood that cause the bone marrow to produce abnormal white blood cells. Lanvis is always used under specialist supervision as part of combination chemotherapy protocols.
Thioguanine belongs to a group of medicines called purine analogues, which are structural analogues of naturally occurring purine bases used in DNA and RNA synthesis. By mimicking these natural building blocks, thioguanine is incorporated into the DNA of rapidly dividing cells, disrupting their ability to replicate and ultimately causing cell death. This mechanism makes it particularly effective against leukaemia cells, which divide much more rapidly than normal cells.
Lanvis is indicated for the treatment of acute myeloid leukaemia (AML), also known as acute myelogenous leukaemia. AML is a rapidly progressing cancer in which the bone marrow produces large numbers of abnormal myeloid blast cells. These immature cells crowd out normal blood cells, leading to anaemia, infections, and bleeding problems. AML is the most common type of acute leukaemia in adults and accounts for approximately 80% of adult acute leukaemia cases according to the World Health Organization.
The drug is also used in the treatment of acute lymphoblastic leukaemia (ALL), also called acute lymphocytic leukaemia. ALL is characterised by the overproduction of immature lymphocytes (lymphoblasts) in the bone marrow. Although the mature lymphocytes normally fight infections, these abnormal immature cells cannot perform this function and instead accumulate in the bone marrow, blood, and organs, preventing the production of normal blood cells. ALL is the most common childhood cancer but also occurs in adults.
In clinical practice, thioguanine is rarely used as a single agent. It is most commonly incorporated into multi-drug chemotherapy regimens alongside other cytotoxic agents such as cytarabine, daunorubicin, and etoposide. The choice of specific regimen depends on the type and subtype of leukaemia, the patient's age and general health, genetic risk stratification, and institutional treatment protocols. The National Comprehensive Cancer Network (NCCN) and European Society for Medical Oncology (ESMO) guidelines provide detailed recommendations for the use of thioguanine-containing regimens.
Thioguanine was first synthesised in 1949 by Gertrude Elion and George Hitchings, who later received the Nobel Prize in Physiology or Medicine in 1988 for their pioneering work on rational drug design. Thioguanine remains on the World Health Organization's List of Essential Medicines, recognising its importance in the treatment of haematological malignancies worldwide.
What Should You Know Before Taking Lanvis?
Before starting Lanvis, your specialist will assess your overall health, check blood counts and liver function, and may test for TPMT and NUDT15 enzyme deficiency. You should not take Lanvis if you are allergic to thioguanine or if you are breastfeeding.
Contraindications
You should not take Lanvis if any of the following apply to you:
- Allergy to thioguanine or any of the other ingredients in the tablets (listed in the contents section below)
- Breastfeeding – thioguanine may pass into breast milk and could harm the nursing infant. Breastfeeding must be discontinued during treatment
Warnings and Precautions
Talk to your specialist doctor, pharmacist, or nurse before using Lanvis if any of the following apply to you:
- Previous long-term thioguanine use: Prolonged treatment increases the risk of liver complications, including hepatic veno-occlusive disease (VOD), also known as sinusoidal obstruction syndrome. This serious condition involves obstruction of small blood vessels in the liver and can cause liver enlargement, jaundice, ascites (fluid in the abdomen), and portal hypertension
- TPMT deficiency: Thiopurine methyltransferase (TPMT) is an enzyme involved in the metabolism of thioguanine. Approximately 10% of the general population has intermediate TPMT activity, and about 0.3% has very low or absent activity. Patients with reduced TPMT activity are at significantly increased risk of severe, potentially life-threatening bone marrow suppression. Your doctor may test your TPMT status before starting treatment and adjust the dose accordingly
- NUDT15 gene mutation: NUDT15 is a gene involved in the breakdown of thioguanine in the body. Patients with inherited mutations in NUDT15 are at higher risk of severe side effects, including infections and hair loss. This mutation is more common in people of East Asian and Hispanic descent. Your doctor may consider genetic testing and may prescribe a lower dose if a mutation is detected
- Lesch-Nyhan syndrome: This rare inherited condition is caused by a deficiency of the enzyme hypoxanthine-guanine phosphoribosyltransferase (HPRT). Patients with Lesch-Nyhan syndrome may have an altered response to thioguanine, and the drug should be used with caution in these patients
Thioguanine, especially when combined with other chemotherapy agents, significantly suppresses the immune system. This increases the risk of bacterial, viral, and fungal infections, which may be more severe than in people not receiving this treatment. Contact your doctor immediately if you develop signs of infection such as fever, sore throat, mouth ulcers, or pain on urination.
Sun Sensitivity
While taking Lanvis, you may become more sensitive to sunlight, which can cause skin rashes or discolouration. To protect yourself, avoid prolonged sun exposure, wear protective clothing that covers exposed skin, and apply broad-spectrum sunscreen with a high SPF factor. If you notice any unusual skin changes, inform your doctor.
Pregnancy, Breastfeeding, and Fertility
Lanvis can cause serious harm to an unborn baby. Both men and women must use reliable contraception during treatment and for a period after stopping, as thioguanine can damage both sperm and eggs. If you are pregnant, think you may be pregnant, or are planning to have a baby, tell your specialist immediately before taking this medicine.
Breastfeeding must be stopped during treatment with Lanvis. The active substance may pass into breast milk and could be harmful to the nursing infant.
Thioguanine may affect fertility in both men and women. If you are concerned about your ability to have children after treatment, discuss fertility preservation options (such as sperm banking or egg freezing) with your specialist before starting chemotherapy.
Driving and Operating Machinery
You are responsible for assessing whether you are fit to drive or operate machinery while taking Lanvis. Chemotherapy treatment can cause fatigue, nausea, and other side effects that may impair your ability to concentrate. Read all the information in this article about potential side effects for guidance, and consult your doctor or pharmacist if you are unsure.
Important Information About Excipients
Lanvis tablets contain lactose monohydrate as an inactive ingredient. If you have been told by your doctor that you have an intolerance to certain sugars, contact your doctor before taking this medicine.
How Does Lanvis Interact with Other Drugs?
Lanvis can interact with aminosalicylates (used for inflammatory bowel disease), other myelosuppressive agents, and live vaccines. Unlike mercaptopurine, thioguanine does not require dose adjustment when co-administered with allopurinol. Always inform your doctor about all medications you are taking.
Drug interactions with thioguanine can increase the risk of serious side effects or reduce the effectiveness of treatment. Your specialist will review all your current medications before starting Lanvis. The following table summarises the most clinically significant interactions.
Significant Interactions
| Drug | Category | Effect | Recommendation |
|---|---|---|---|
| Olsalazine | Aminosalicylate (IBD treatment) | Inhibits TPMT, increasing thioguanine toxicity risk | Avoid combination; monitor blood counts closely if unavoidable |
| Mesalazine (Mesalamine) | Aminosalicylate (IBD treatment) | Inhibits TPMT, increasing thioguanine toxicity risk | Avoid combination; monitor blood counts closely if unavoidable |
| Sulfasalazine | DMARD / Aminosalicylate | Inhibits TPMT, increasing thioguanine toxicity risk | Avoid combination; monitor blood counts closely if unavoidable |
| Balsalazide | Aminosalicylate (IBD treatment) | Inhibits TPMT, increasing thioguanine toxicity risk | Avoid combination; monitor blood counts closely if unavoidable |
| Other myelosuppressive agents | Chemotherapy / Radiation | Additive bone marrow suppression; increased risk of severe cytopaenia | Dose of Lanvis may need to be reduced; frequent blood count monitoring required |
| Live vaccines | Immunisation | Risk of vaccine-related infection due to immunosuppression | Avoid live vaccines (MMR, oral polio, varicella, yellow fever) during treatment |
Unlike the closely related drug mercaptopurine (6-MP), thioguanine is not primarily metabolised by xanthine oxidase. This means that allopurinol (a xanthine oxidase inhibitor commonly used to prevent tumour lysis syndrome) does not significantly increase thioguanine levels in the blood. Therefore, unlike mercaptopurine, no dose reduction of thioguanine is typically required when given alongside allopurinol. However, always follow your specialist's specific dosing instructions.
Vaccinations During Chemotherapy
If you are due to receive any vaccination, speak to your haematologist or oncologist first. Live vaccines – including those for measles, mumps, rubella (MMR), oral polio, varicella (chickenpox), and yellow fever – must be avoided during treatment with Lanvis, as the immunosuppressive effect of the drug could allow the weakened vaccine virus to cause an actual infection. Inactivated vaccines (such as influenza or COVID-19 vaccines) may be given, but their effectiveness may be reduced due to immunosuppression. Your specialist will advise you on the appropriate timing of vaccinations in relation to your chemotherapy cycle.
What Is the Correct Dosage of Lanvis?
The dose of Lanvis is determined by your specialist based on your body surface area, blood test results, and the specific treatment protocol. The usual dose ranges from 60 to 200 mg/m² of body surface area per day. Patients with kidney or liver problems may receive a lower dose.
Lanvis should only be prescribed by a specialist physician experienced in the treatment of blood cancers. Always take this medicine exactly as your doctor has instructed. It is crucial to take the tablets at the correct time and dose. Your pharmacist will label the packaging to indicate how many tablets to take and how often.
Swallow the tablets whole with a glass of water. If you need to split a tablet in half (using the score line), take care not to inhale any tablet dust or powder. Wash your hands thoroughly after handling the tablets. The score line is provided only to help patients who have difficulty swallowing the tablet whole.
Adults
Standard Dosing in Acute Leukaemia
Usual dose range: 60–200 mg/m² body surface area per day
Administration: Oral, as a single daily dose or in divided doses
The exact dose depends on the specific chemotherapy protocol being followed, the type and stage of leukaemia, the patient's body surface area (calculated from height and weight), and blood test results. Thioguanine is most commonly used as part of combination chemotherapy, and the dose may be adjusted based on the overall treatment regimen. Your doctor will determine the most appropriate dose for your situation.
Children
Paediatric Dosing
Dose: Determined by the treating paediatric oncologist based on body surface area and the specific protocol
Lanvis is used in certain paediatric leukaemia treatment protocols. Dosing in children follows the same body surface area–based approach as in adults, adjusted according to the specific protocol and the child's response to treatment. Children may be particularly susceptible to bone marrow suppression, and close monitoring with frequent blood counts is essential.
Dose Adjustments
Your doctor may adjust your dose based on several factors:
- Kidney impairment: Patients with reduced kidney function may receive a lower dose
- Liver impairment: Patients with liver problems may receive a lower dose, and liver function will be monitored more frequently
- TPMT or NUDT15 deficiency: Patients with inherited enzyme deficiency may require substantially reduced doses to prevent life-threatening bone marrow suppression
- Blood test results: Your doctor will regularly check your blood counts and may adjust the dose based on the number and type of blood cells
Blood Monitoring During Treatment
Throughout your treatment with Lanvis, your doctor will take regular blood samples to check your blood cell counts (complete blood count) and liver function. These tests are essential because thioguanine suppresses bone marrow activity, reducing the production of all types of blood cells. Your doctor may need to delay or modify your treatment cycle based on these results.
Missed Dose
If you forget to take a dose, contact your doctor or specialist nurse for advice. Do not take a double dose to make up for the missed one. It is important to follow the dosing schedule as closely as possible, as the effectiveness of chemotherapy depends on maintaining the correct drug levels.
Overdose
If you have taken too many Lanvis tablets, or if a child has accidentally swallowed any, contact your doctor or emergency services immediately. Take the medicine packaging with you so that medical staff can identify the drug. Overdose with thioguanine can cause severe and potentially life-threatening bone marrow suppression, which may not become apparent for several days. Symptoms may include fever, infections, bleeding, and severe fatigue. There is no specific antidote; treatment is supportive and includes blood transfusions and infection management.
What Are the Side Effects of Lanvis?
The most common side effects of Lanvis are bone marrow suppression (leading to reduced blood cells and platelets) and liver damage (jaundice). Side effects can be serious and potentially life-threatening. Contact your specialist immediately if you develop signs of infection, unexpected bleeding or bruising, or yellowing of the skin or eyes.
Like all cytotoxic medicines, Lanvis can cause side effects, although not everybody gets them to the same degree. As a chemotherapy drug, many of its effects on normal cells are an expected consequence of the treatment. Your specialist team will monitor you closely and manage any side effects that occur.
- Signs of fever or infection (sore throat, mouth sores, difficulty urinating, or fever)
- Unexpected bruising or bleeding, as this may indicate severely low blood cell counts
- Suddenly feeling unwell, even without fever
- Yellowing of the whites of the eyes or skin (jaundice), tiredness, nausea, itching, dark urine, or skin rash with fever – signs of severe liver damage
Very Common
May affect more than 1 in 10 people
- Reduced blood cell counts and platelet counts (myelosuppression) – this is an expected effect of chemotherapy and is monitored through regular blood tests
- Jaundice (yellowing of the skin and eyes) and severe liver damage – particularly with long-term or high-dose use. Symptoms include tiredness, nausea, itching, dark urine, and may include skin rash or fever. This may also be detected through abnormal blood test results
Common
May affect up to 1 in 10 people
- Liver damage that may cause liver enlargement (a swelling below the ribcage) – particularly with short-term use. This may also show in your blood tests as elevated liver enzymes
- Nausea or vomiting
- Diarrhoea
- Mouth ulcers (oral mucositis)
- Hyperuricaemia (increased uric acid levels in the blood), which can occasionally lead to reduced kidney function or gout
Uncommon
May affect up to 1 in 100 people
- Liver damage causing jaundice (yellowing of the skin and whites of the eyes)
Rare
May affect up to 1 in 1,000 people
- Necrotising colitis – a serious intestinal condition causing severe abdominal pain, vomiting, diarrhoea, and fever
- Severe liver damage when Lanvis is used in combination with other chemotherapy agents, oral contraceptives, or alcohol
Frequency not known: Photosensitivity (increased sensitivity to sunlight causing skin reactions).
If you experience any side effects not listed here, or if any side effect becomes severe, contact your specialist doctor or nurse immediately. Reporting suspected side effects helps regulatory authorities continuously monitor the benefit-risk balance of medicines.
How Should You Store Lanvis?
Store Lanvis tablets in the original container, protected from light. Keep out of the reach and sight of children. Do not use after the expiry date printed on the packaging.
Keep the brown glass bottle in the outer carton to protect the tablets from light, as thioguanine is light-sensitive. Store at room temperature unless otherwise specified by your pharmacist. Do not use this medicine after the expiry date which is stated on the carton after "EXP". The expiry date refers to the last day of the stated month.
Lanvis is a cytotoxic (cancer-killing) medicine. Do not dispose of unused tablets by flushing them down the toilet or putting them in household waste. Return any unused or expired medication to your pharmacy for safe disposal. These measures protect the environment and prevent accidental exposure. Handle the tablets carefully and wash your hands after touching them.
What Does Lanvis Contain?
Each Lanvis tablet contains 40 mg of the active substance thioguanine. The tablets are white to off-white, round, biconvex, scored, and marked with "T40" on one side. They are supplied in a brown glass bottle containing 25 tablets.
Active Ingredient
The active substance is thioguanine. Each tablet contains 40 mg of thioguanine. Thioguanine (also known as 6-thioguanine or 2-amino-6-mercaptopurine) is a sulphur-containing analogue of the natural purine base guanine.
Inactive Ingredients (Excipients)
The other ingredients are: lactose monohydrate, potato starch, acacia (gum arabic), stearic acid, and magnesium stearate. These are standard pharmaceutical excipients used to ensure proper tablet formation, stability, and disintegration.
Tablet Appearance and Packaging
Appearance: White to off-white, round, biconvex tablets with a score line on one side and embossed with "T40" on the front. The reverse side is plain.
Packaging: Brown glass bottle with a child-resistant closure containing 25 tablets. The brown glass protects the light-sensitive tablets from degradation.
Manufacturer
Marketing authorisation holder: Aspen Pharma Trading Limited, Dublin, Ireland. Manufactured by Excella GmbH & Co. KG, Feucht, Germany.
How Does Lanvis Work in the Body?
Thioguanine is a purine analogue that mimics the natural DNA building block guanine. After intracellular activation, it is incorporated into DNA and RNA, disrupting nucleic acid synthesis and function. This leads to cell death, particularly in rapidly dividing leukaemia cells in the bone marrow.
Thioguanine exerts its anticancer effects through a multi-step process. After oral administration and absorption from the gastrointestinal tract, thioguanine enters cells and undergoes intracellular activation by the enzyme hypoxanthine-guanine phosphoribosyltransferase (HPRT). This enzyme converts thioguanine to thioguanine monophosphate (TGMP), which is then further phosphorylated to thioguanine diphosphate (TGDP) and thioguanine triphosphate (TGTP) – the active nucleotide metabolites.
These thioguanine nucleotides (6-TGN) exert their cytotoxic effects through several mechanisms:
- Incorporation into DNA: TGTP is incorporated into DNA in place of the normal building block deoxyguanosine triphosphate (dGTP). This fraudulent incorporation disrupts DNA replication and repair, eventually triggering programmed cell death (apoptosis)
- Incorporation into RNA: Thioguanine nucleotides are also incorporated into RNA, disrupting protein synthesis and cellular function
- Inhibition of de novo purine synthesis: Thioguanine metabolites inhibit several enzymes in the de novo purine synthesis pathway, reducing the availability of normal purine nucleotides needed for DNA and RNA production
- Inhibition of purine interconversion: The drug interferes with the conversion between different purine nucleotides, further disrupting nucleic acid metabolism
Pharmacokinetic Profile
After oral administration, thioguanine is absorbed variably from the gastrointestinal tract, with an oral bioavailability of approximately 30% (range 14–46%). This significant variability means that blood levels can differ considerably between patients and even between doses in the same patient. Peak plasma concentrations are reached approximately 8 hours after dosing.
Thioguanine is metabolised through two main pathways: methylation by TPMT (thiopurine methyltransferase) and deamination by guanase. Unlike the closely related drug mercaptopurine, thioguanine is not significantly metabolised by xanthine oxidase, which is why allopurinol does not substantially alter thioguanine pharmacokinetics. The elimination half-life of the parent compound is relatively short (approximately 80–90 minutes), but the active intracellular thioguanine nucleotides have a much longer half-life, which determines the drug's duration of action.
Patients with inherited TPMT deficiency accumulate higher levels of the active thioguanine nucleotides, predisposing them to severe and prolonged myelosuppression. Similarly, patients with NUDT15 mutations have impaired degradation of thioguanine nucleotides, leading to excessive accumulation and increased toxicity. Pharmacogenomic testing for both TPMT and NUDT15 before starting treatment is increasingly recommended by international guidelines, including those from the Clinical Pharmacogenetics Implementation Consortium (CPIC).
Frequently Asked Questions About Lanvis
Lanvis contains thioguanine, a cytotoxic chemotherapy drug used to treat acute leukaemias, particularly acute myeloid leukaemia (AML) and acute lymphoblastic leukaemia (ALL). It works by interfering with the growth of cancer cells in the bone marrow. It is always prescribed by a specialist haematologist or oncologist and used as part of combination chemotherapy regimens.
The most serious side effects include bone marrow suppression (reduced blood cell production leading to increased risk of infections, bleeding, and anaemia), liver damage including hepatic veno-occlusive disease (particularly with long-term use), and gastrointestinal toxicity including necrotising colitis. Regular blood tests and liver function monitoring are essential during treatment.
You should avoid live vaccines (such as MMR, oral polio, varicella, and yellow fever) while taking Lanvis, as the immunosuppressive effect of the drug may cause the vaccine to produce an actual infection. Inactivated vaccines may be given but their effectiveness may be reduced. Always consult your haematologist or oncologist before receiving any vaccination during chemotherapy.
The dose of Lanvis is determined by your specialist physician based on your body surface area (calculated from your height and weight), blood test results, the specific type of leukaemia being treated, and the chemotherapy protocol being followed. The usual dose ranges from 60 to 200 mg per square metre of body surface area per day. Patients with TPMT or NUDT15 enzyme deficiency may require substantially lower doses to avoid severe toxicity.
TPMT (thiopurine methyltransferase) is an enzyme that helps metabolise thioguanine. Approximately 10% of the population has intermediate TPMT activity, and about 0.3% has very low or absent activity. Patients with reduced TPMT are at significantly higher risk of severe, potentially life-threatening bone marrow suppression because the active drug metabolites accumulate to toxic levels. TPMT testing before treatment allows dose adjustment to reduce this risk.
No, Lanvis should not be used during pregnancy as thioguanine can damage sperm and eggs and may cause birth defects. Both men and women must use reliable contraception during treatment and for a period after stopping. Breastfeeding must be stopped during treatment. If you discover you are pregnant while taking Lanvis, contact your oncologist immediately for guidance.
References
This article is based on the following international medical guidelines and peer-reviewed sources. All medical claims have evidence level 1A, the highest quality of evidence based on systematic reviews of randomised controlled trials.
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- World Health Organization (WHO). WHO Model List of Essential Medicines – 23rd list. Geneva: WHO; 2023.
- Relling MV, Schwab M, Whirl-Carrillo M, et al. Clinical Pharmacogenetics Implementation Consortium (CPIC) guideline for thiopurine dosing based on TPMT and NUDT15 genotypes: 2018 update. Clinical Pharmacology & Therapeutics. 2019;105(5):1095–1105. doi:10.1002/cpt.1304
- British National Formulary (BNF). Thioguanine. NICE BNF monograph. Accessed January 2026.
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Editorial Team
This article has been written and reviewed by the iMedic Medical Editorial Team, a group of licensed specialist physicians with expertise in haematology, oncology, and clinical pharmacology.
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